OPERATION AND MAINTENANCE MANUAL. NVS Duct Air Conditioning Units. DTR-NVS-ver.2.30 ( )

Transcription

1 OPERATION AND MAINTANCE MANUAL NVS Duct Air Conditioning Units DTR-NVS-ver.2.30 ( )

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3 CONTTS 1. INTRODUCTION DESTINATION CONSTRUCTION Fan section Water heater section Electric heater section Filter section Silencing section Cross-flow exchanger section DELIVERY, TRANSPORT, STORAGE ASSEMBLY AND CONNECTIONS Installation of a suspended unit Place of assembly Connecting ventilation ducts Installation of flexible connections and air dampers Installation of silencing curtains Installation of plate cross-flow exchanger Connecting heaters and coolers Draining out condensate Electrical connections Fan motor Electric heater Automatics PREPARATION FOR START-UP Electric system Filters Water heaters Electric heaters Water and freon coolers

4 6.6. Plate cross-flow exchanger Fan assembly START UP AND ADJUSTMTS Air volume measurements and AHU capacity adjustments Adjusting the capacity of the thermal water heater Elecric heater adjustments Adjusting the capacity of the cooler OPERATION AND MAINTANCE AIR DAMPERS Filters Heat exchangers Water heater Electric heater Water or glycol cooler Freon cooler Silencing section Fan set Fans Motors Control measurements INDUSTRIAL SAFETY MANUAL INFORMATION Technical information to the regulation (EU) No 327/2011 implementing Directive 2009/125/EC

5 1. INTRODUCTION The operation and maintenance manual refers to N-Type type duct AHUs manufactured by VTS. It includes a set of basic information and recommendations regarding the construction, assembly, start up and operation which if observed will certainly ensure correct and failure free operation of the AHU. You should read the manual carefully, use the AHU according to all specifications included in the manual as well as observe all safety requirements to guarantee proper and safe operation of the unit. Works concerning the procedure of unloading pallets with AHU components, transporting pallets, elements and AHU sections, connecting all systems related to the AHU as well as maintenance works should be performed by qualified staff or supervised by authorised persons. Qualified staff means people, who, as a result of a particular training, experience and knowledge of important standards, documentation and industrial safety regulations, have been authorized to carry out indispensable works and are able to recognise and avoid potential threats. This operation and maintenance manual does not include any detailed information regarding any possible AHU configurations, sample assemblies and installations, start-ups, operation, repairs or maintenance works. If AHUs are operated according to their purpose, this operation and maintenance manual as well as other documentation attached to the AHU should include enough information necessary for qualified staff. AHU assembly, connecting related installations, start-up, operation and maintenance Works must be performer in accordance with directives and regulations valid in the territory of the country where the particular AHU has been installed. Warranty repairs of VTS AHUs can only be performed by Authorized VTS Service Center, having an appropriate certificate allowing this type of Works. We also recommend that Authorized VTS Service Center should carry out assemblies, start-ups, post-warranty repairs, overhauls and maintenance works performed on AHUs. The manual should always be available near the AHU providing easy access for service workers. 2. DESTINATION N-Type duct AHUs are manufactured in sections designed for assembly in a series of ventilation ducts. The typeline of 4 sizes covers the capacity range from 2200 to 8500m3/h (of the nominal value). AHUs are equipped with a wide range of functional sections which offers extensive possibilities of realizing the air treatment process starting from the simplest supply and exhaust to conditioning the supplied air in the field of such parameters as temperature (heating: water of electric heaters, cooling: water or freon coolers), filtration, primary and secondary filters as well as noise level reduction (we offer silencing curtains without any casing to be assembled inside a duct). N-Type devices are designed for the operation with inlet air with temperatures range from -40oC to +50oC. These devices are not to be installed outside any building. AHUs are only available in the right orienta. 3

6 3. CONSTRUCTION Fig.1. AHU orientation side Duct AHUs consist of freely configurable sections in two types of casing: with insulation (for the fan section) and without it (for all the remaining sections). Each of delivered sections is marked with the use of graphic symbols representing particular functions placed on the casing Fan section Fan sections are made on the basis of blocks with the frameless construction (Fig.2). Casings, with the wall thickness of 40 mm in the form of panels bent in the O letter shape made of self-extinguishing polyurethane foam with the density of at least 40 kg/m3 covered on both sides with 0.4mm thick galvanized sheet metal plate. The fan section is constructed in two versions; including the cooler (a water or a freon one) and without the exchanger (fan only). The section does not have the inspection panel and the access to the fan is provided only from the side of the AHU s outlet (after disassembling the duct). Fig 2. Fan section 4

7 Tab.1. Fan section s dimensions Size W Wi H Hi WCL3R (with the water cooler) L [мм] DX3R (with the Freon cooler) V (without the exchanger) NVS NVS NVS NVS a) b) Fig.3. Cooler a) water, b) freon Tab.2. Cooler dimensions SIZE LL LD LH TH TR φdin φdout C Number of rows Exchanger capacity [l] NVS23 3R DN25 DN ,6 NVS39 3R DN25 DN ,1 NVS65 3R DN32 DN ,4 NVS80 3R DN32 DN ,9 NVS23 DX /8" ,6 NVS39 DX /8" ,1 NVS65 DX /8" ,4 NVS80 DX /8" ,9 AHUs are equipped with fans without any casing and with direct drive from the three-phase asynchronous motor with the possibility of smooth adjustment of the rotation speed with the use of the frequency converter. 5

8 Tab.3. Motor Types and AHU capacities Size Fan Max capacity Motor Type VCW [m 3 /h] VHW [m 3 /h] Type NVS23 VS M-0.55/2p NVS39 VS M-1.1/2p NVS65 VS L-2.2/2p NVS80 VS M-4/2p The fan section with the cooler is equipped with plugged holes on both sides of the AHU through which (after removing the plug) wash pipes can be led in order to disinfect the basin and the exchanger Water heater section The exchanger only without any casing constitutes water heater section: Fig.4. Water heater section Tab.4. Dimensions of the water heater Size LL LD LH HR H TH TR φd φd Number of rows Exchanger capacity [l] NVS NVS NVS NVS ,5 DN , , ,3 DN , ,0 DN , ,1 DN ,2 6

9 3.3. Electric heater section The electric heater section consists of a casing made of galvanised sheet metal plate with 1 (NVS23) or two row of heaters (NVS39-80). The power of a single heater is 2kW for the supply of ~230V and 6kW for the supply of ~400V. Each heater is equipped with a counter-overheating thermostat with cables led out to a connection block (1) located under the inspection panel (2). Tab.5. Dimensions of the electric heater Fig.5. Electric heater section Size W Wi H Hi L Number of heaters max. power [kw] NVS NVS NVS NVS Filter section The casing of the filtration section is made of galvanised sheet metal plate (without insulation). Depending on the kind and the class of the filter we can distinguish between three lengths of sections. Filters are slid in guides and closed with a cover from the bottom or the top of the section (depending on assembly manner) There are two kinds of filters available: 1) EU4 class panel filter 2) EU5 and EU7 class bag filter Fig.6. Filtration section 7

10 Tab.6. Measurements of the filtration section Size W Wi H Hi NVS NVS NVS NVS L P.FLT.SET B.FLT.SET EU5 B.FLT.SET EU Silencing section The silencing section consists of silencing curtains to be installed inside ventilation ducts. Silencing sections are delivered in sets of 2 or 3 pieces depending on the size. Silencing sections are based on a composite frame filled with mineral wool 140mm thick and with the density of 35kg/m 3. Fig.7. Silencing curtain Tab.7. Sizes of silencing curtains Size W H L Number of curtains in a set NVS NVS NVS NVS Cross-flow exchanger section Cross-flow exchanger section as the other NVS sections (except fan section), is supplied without the insulating casing for installation in the ventilation duct system. 8

11 Tab.8. Cross-flow exchanger dimension Fig.8. Plate cross-flow recuperator Size Tab.9. Cross-flow exchanger parameters H L B D m NVS NVS NVS NVS Size range of air flow eficiency max. eficiency min. min. air speed max. air Speed min. pressure drop max. pressure drop m3/h % % m/s m/s Pa Pa min.-max supply/ exhaust supply/ exhaust supply/ exhaust supply/ exhaust NVS ,1 / 1,9 3,5 / 3,1 63 / / 140 NVS ,0 / 1,8 3,9 / 3,5 59 / / 170 NVS ,0 / 1,8 3,9 / 3,5 60 / / 170 NVS ,9 / 1,7 3,9 / 3,4 59 / / DELIVERY, TRANSPORT, STORAGE AHUs are delivered to the installation site in the form of separate blocks. Immediately after receiving devices it is necessary to verify the condition of the package as well as completeness of the delivery on the basis of attached specification and bills of fading. Unloading AHUs, transporting them to the installation site should be performed manually, with the use of a pallet-lift truck or a fork lift. While transporting AHU sections special attention should be paid to careful lifting and lowering the sections It is not allowed to transport or store fan sections placed on one of its side casing walls. It can result in damaging the fan drive system. It is recommended that the sections are transported according to the marking placed on the package. 9

12 Packages must be stored on site placed on hardened, dry surface secured from rainfall. Hardened surface means flat, level and hard surface that does not change its properties due to different weather conditions. Packages including AHU sections should be stored away from the area with operating vehicles (cars, cranes and construction machinery) in a place where they are not expose to mechanical damage, humidity, aggressive chemical environment, dust, sands and other external factors that may cause deterioration of the packages condition. Any damage resulting from inappropriate conditions of freight and storage will not be covered by the warranty and all claims referring the above must be submitted to the forwarder. Devices must be stored in rooms where: - maximum air humidity does not exceed 80 % with the temperature of 20 o C - ambient temperature is between 20 o C and + 30 o C - devices are protected from dust, caustic gas and steams as well as corrosive chemical substances that May damage the elements of construction or the equipment of devices. 5. ASSEMBLY AND CONNECTIONS As standard, NVS AHUs are assembled in horizontal suspended position. It is also possible to install them in horizontal lying position. It is prohibited to operate AHUs placed horizontally on a wall (with its side parallel to the ceiling) or vertically Installation of a suspended unit Assembly of AHU sections in a line of ventilation ducts is carried out with the use of standard elements (not being the subject of delivery) used for suspending ventilation ducts. For the assembly of ducts or other sections for the fan section (Fig.9 item.1) self-driving screws must be applied. To join other sections both self-driving screws and other joining elements available on the market can be applied. (Fig.9 item.2 and 3). The place where two sections are joined must be secured with self-adhesive seal (for each section there is seal for one connection provided). During section instalation, pay attention to the air direction. 10

13 5.2. Place of assembly Fig.9. Way of joining sections During assembly and fitting AHU covers (e.g. suspended ceilings) it is necessary to predict the necessity of exchanging filters in the future, carrying out a minor repair or exchanging the entire section. The AHU should be installed in a way allowing connection of related installations (pipelines, cable ducts) without interference to the inspection panels Connecting ventilation ducts Optionally, there are flexible connections delivered with AHUs. They prevent transmission of vibration and eliminate minor deviations in the concentricity of the duct and the AHU itself. Appropriate operation of the flexible connection is ensured after stretching the sleeve to the length of approx. 110 mm. Ducts joined with the AHU must be supported or suspended on their own supporting elements. The manner of leading ducts together with all profiles should eliminate any possibility of increasing the noise level in the ventilation system Installation of flexible connections and air dampers The way of installing flexible connection is demonstrated in Fig. 9. For the installation of flexible connections and air dampers for the fan section self-driving screws should be applied (Fig.9 item.1). In order to join these elements with other sections both self-driving screws and other joining elements available on the market can be applied. Flexible connections are ended with flanges with seals Installation of silencing curtains Figure 10 illustrates a sample way of installing silencing curtains in a duct where the curtains are screwed down to the ceiling of the floor with screws through an additional mounting element (not included in VTS delivery). Curtains should be distributed at even intervals. 11

14 5.6. Installation of plate cross-flow exchanger Fig.10. Sample way of installing silencing curtains Plate cross-flow exchanger delivered as a separate part should be connect with other NVS sections on the no pressure side of supply and on the pressure side for the exhaust. Don t connect the cross-flow exchanger with exhaust fan section on the no pressure side. At the assembly of the cross-flow exchanger in the ventilation duct system is needed performing the isolation of the cross-flow exchanger condensate outflow. In case of heat recovery condensate outflow should be made on the exhust duct after cross-flow exchanger. In case of summer recovery between cross-flow exchanger and next supply section should be used piece of the duct where will installed condensate outflow. Fig.11. shows the connection manner of NVS sections with cross-flow exchanger. For that self-drilling screws (not being the subject of delivery) must be used. Fig.12. is presenting the example of configurations of NVS sections with the cross exchanger with the application additional connection elements (not being the subject of delivery). 12

15 Exhaust Supply Fig.11. Connection of NVS sections with cross-flow exchanger Exhaust Supply Additional connection elements not being the subject of VTS delivery Exhaust Supply 5.7. Connecting heaters and coolers Fig.12. Connection of NVS sections with cross-flow exchanger Connecting exchangers should be performed in a way that prevents the occurrence of stress that may result in mechanical damage or leakages. Neither the weight of the pipeline nor thermal stress can be transferred to the exchanger s connection pins. Depending on local conditions it is necessary to apply compensation in the pipeline system on supply and return in order to reduce linear expansion of the pipeline. During the installation of the supply system for exchangers equipped with SCR connections, the connection pin of the exchanger should be countered with the use of an additional key (Fig.13). The applied way of connecting exchangers with the supply system should enable smooth removal of the pipeline in order to guarantee collision free removal of AHU sections during maintenance and reparation works. 13

16 Fig.13. Connecting exchangers Supply and return connection pins of exchangers should be connected in such a way that the exchanger can operate in a counter-current circuit. Operation in a co-current circuit results in reducing the average temperature difference influencing the exchanger s capacity. Diagrams demonstrating appropriate connection of supply and return pipelines depending on the direction of air flow are provided in figure 14. The pins of exchangers are additionally marked with stickers. HW CW a) water heater supply b) water cooler supply c) Freon cooler supply Fig. 14. Heater and cooler supply 14

17 The connection of the freon cooler should be made by a qualified assembler of cooling installations in accordance with the rules regarding freon cooling devices (Fig.14 c) Draining out condensate There is an SCR ending (G1 ) located in the floor of the fan section with the cooler to which a siphon (not included in VTS delivery) should be connected. Its aim is to drain out condensed water from the exchanger. Siphon should be skrew in the drain connector with using teflon tape to obtain leak tightness in any position of it. The height H of siphon depends on the difference of pressures between the pressure in the AHU section, where condensate is drained out during and the ambient pressure. H" dimension is provided in mm and must be high er than the pressure difference expressed in mmh2o. Tab.10. Height of the water seal Nr Fan s total pressure [Pa] Dimension H 1. < H1=H+56 a) c) b) H H Fig.15. Ball water seal - suction Due to different pressure values in sections during the AHU s operation it is not allowed to connect several drip outflow pins with the use of a single water seal. Before starting an AHU water seals should be flooded with water. In a cold environment the outflow should be isolated. If it is necessary you should apply an appropriate heating system. On the piece of duct after the cross-flow exchanger should be performed the outflow of condensate. 15

18 5.9. Electrical connections Fig.15.d. Example of the performance of the condensate outflow on the duct Electric connections of AHU equipment elements should be carried out by well qualified and authorized workers and in accordance with appropriate standards and regulations valid in the territory of a country the particular unit is installed. Cross-sections and types of supply cables (e.g. screened cables) individual elements of the functional equipment should be adjusted to the nominal current and conditions specific for the place of the AHU s location. (e.g. ambient temperature, arrangement of cables, distance from the powering switchgear). Before connecting power supply it is necessary to check the compatibility of the voltage and the frequency of the power network with the specification provided on the rating plates of devices. Acceptable deviations in the frequency of power voltage, in relation to the information provided on the rating plate, range between ±5% and ±2%. If there is any inconsistency devices should not be connected Fan motor Fan motors are designed for operation in dusty and humid environment (IP55) and their insulation (F class) is designed to cooperate with the frequency converter. No additional measures are required to immune the motors to the influence of conditions in the AHU s fan section. As standard motors applied in AHUs are motors with their own cooling with a fan built over on the shaft. Power cables for the fan motor are lead into the connection clamp box outside the AHU. The connections should be performed according to the diagram (Fig.16). 16

19 Fig.16. Electric diagrams demonstrating the recommended connection and steering of the fan set a) NVS (1) - recommended cabling for custom made controls (2) - cabling for dedicated NVS CG control boxes (3) - cabling for frequency converter-powered units 17

20 Fig.16. Electric diagrams demonstrating the recommended connection and steering of the fan set b) NVS 80 (1) - recommended cabling for custom made controls (2) - cabling for dedicated NVS CG control boxes (3) - cabling for frequency converter-powered units 18

21 Electric connection of the fan should be carried out before assembling the duct from the pressing side of the fan section to make sure the rotation direction is appropriate. Tab.11. Parameters of electric motors AHU size Motor type Rated power Rated rotation Power voltage Rated current Mechanical size of the motor Maximum frequency [kw] [1/min] [V] [A] [IEC] Hz NVS23 71M-0.55/2p 0, x230V/3x400V 2,4/1,36 71M 50 NVS39 80M-1.1/2p 1, x230V/3x400V 4,2/2,40 80M 50 NVS65 90L-2.2/2p 2, x230V/3x400V 7,9/4,55 90L 50 NVS80 112M-4/2p x400V/3x690V 7,8/4,5 112M 50 When the motor is powered by the frequency converter high frequency current or harmonic element of current in the cables powering the motor may cause electromagnetic interference. The connection between the frequency converter and the motor should be carried out with the use of screened conductors according to the instructions included in the DTR of the frequency converter. When the motor is powered by the inverter the maximum value of 50Hz corresponding to the maximum capacity of the AHU should not be exceeded Electric heater Power cables for the electric heater should be led through the chokes in the casing. The connection of the heater should be performed in a way that secures it against switching on without the fan on. Besides, in case of disrupting the operation of the fan the heater power must be switched off. Tab.12. Rated parameters of electric heaters Size Heater power [kw] NVS23 18 NVS39 NVS65 NVS Power voltage 3x400 В Rated current L1=L2=L3 [A] Heating coils of the heater can become destroyed in case the power supply is fed with no air owing through. The thermostat is an element protecting against excessive increase of air temperature inside the heater resulting from air ow intensity decay or decrease. The thermostat must be included in the heater control system. The operation of the thermostat is based on the properties of the bimetallic element causing divergence of the contacts of the heater power supply control circuit with the air temperature value in the environment of the thermostat up to 65ºC. After and emergency switch off automatic restart of the heater takes place after the air temperature has dropped to 20ºC. After any planned or emergency switch off (resulting from overheating) of the power supply, the intake ventilator must work for some more time (0,5-5 min) in order to cool down the heating coils of the electric heater. VTS reserves its right to introduce changes without prior noti cation 19

22 20

23 Fig.17. Recommended ways of connecting the electric heater in the NVS AHU 21

24 5.10. Automatics Complete automatics, that should be an integral part of each air conditioning system, enable smooth operation of the device, and, in many cases, constitute an indispensable element which, if missing, can result in exploitation problems and serious damage of devices. Tasks with the use of automatic control and protection adjustment in the field of air treatment realized by functional sets of AHUs, can be performed by a wide range of automatics systems and this documentation does not cover information in the field of assembling elements of automatics, connecting, start up and operation of the system. This information is included in separate documents provided by the supplier of the automatics system. 6. PREPARATION FOR START-UP AHU start-up while putting a particular AHU into use must be carried out only by qualified and trained Staff of the assembly and start-up team. Before start-up it is recommended that some significant preparatory actions are carried out. Most of all you should verify if: - all ventilation devices have been installed mechanically and connected to the ventilation system; - the complete hydraulic and freon systems are installed and prepared for operation and the heating or cooling medium is available during start-up; - electric energy receivers are wired and ready for operation; - water seals and drip outflow system have been fitted; - all automatics elements have been installed and wired Moreover it is necessary to order the construction site, clean both the devices inside and duct installations cooperating with them as well as remove the protective film from the AHU s cover panels. It should also be verified if no element of any device or the system, automatics or its equipment has been damaged in the assembly process 6.1. Electric system On the basis of provided electrical diagrams of installed elements and sub-components it is necessary to check the appropriateness of connection of the electrical system and applied protections of all receivers of electric energy Filters Air filters applied in air conditioning units prevent penetration of dust into the ventilated room. Apart from that they efficiently protect other functional elements of the AHU, especially heat exchangers, against dirt. The AHU must always be operated with its filters fitted. Before you close the filtration section you should: - verify the condition of filters and the leak-tightness of mounting in guides, - verify the settings of differentia pressure controls, (if they are fitted) defining the permissible difference of static pressure qualifying a filter for exchange. Tab.13 Permissible pressure difference on filters acc. to Permissible Filter type and class pressure difference P.FLT G Па B.FLT F 5 F Па 250 Па 22

25 6.3. Water heaters It is necessary to check the following: The appropriateness of the connection of the supply and outflow pipeline, The settings of the counter-freezing themostat (recommended setting to + 5ºC), If the control valve of the heater is installed in accordance with the marking provided on its casing 6.4. Electric heaters It is necessary to check the following: The appropriateness of electrical connections in accordance with the electric diagram of connecting heaters, The appropriateness of connecting the securing thermostat Water and freon coolers Similarly to the water heater it is necessary to check the following: The appropriateness of the connection of the supply and outflow pipeline, The appropriateness of fitting the water seal before AHU start-up the water seal should be flooded with water, Passability of the drip outflow system Plate cross-flow exchanger Before the startup of the unit make sure about correct installation of condensate outflow Fan assembly It is necessary to check the following: The appropriateness of electrical connections in accordance with the electric diagram of connecting the motor All air dampers in the ventilation duct network are set in accordance with the design, The appropriateness of the fan rotation direction in accordance with the arrow placed on the rotor. 7. START UP AND ADJUSTMTS The aim of start-up is to verify that a particular unit has been prepared in accordance with the design and it is ready for operation. The start-up procedure and adjustments of ventilation and air conditioning system can only be performed by a qualified start-up team equipped with a set of basic measuring tools. Having performed activities described in point 5 and 6 you can initiate the start-up procedure. In AHUs equipped with the secondary filtration section it is recommended that they should be launched without any secondary filter cartridge. The fan should be started with reduced load and then adjusted to parameters close to the assumed operation point. Reduced load can be achieved through closing the regulation air choke at the AHU s input and additionally, in case of powering the motor with the frequency converter, by reducing the rotary speed. While increasing the load it is necessary to verify the current consumed by the motor. 23

26 The rule stating that for the design air parameters the intensity of the current powering the fan s motor Carnot exceed the rated value must be strictly observed. Failing to observe the instructions referring the first start-up can result in overloading the fan s motor and its serious damage. After start-up you should verify if: There are no alarming noises and unnatural mechanical sounds, There is no vibration that can be regarded too hi. The AHU should work for about 30 minutes. After this time it should be switched off and undergo an overhaul of individual sections. Special attention should be paid to the following: filters (if they are not damaged), condensate drain-out. It is recommended that before starting the fan air dampers are initially open in the automatics function system. It has influence on the durability and operation of air dampers as well as eliminates the operation of the pressure control signalling no compression. After start-up it is necessary to exchange or clean the initial filters. Obtaining assumed effects in the operation of a ventilation or air conditioning unit depends, among Rother things, on performing adjustments and control measurements Air volume measurements and AHU capacity adjustments. Air volume measurement is a basic measurement in case of the following: Starting-up and technical acceptance of an AHU, When the system fails to operate in accordance with designed assumptions, Periodic control of an AHU s operation, Exchanging elements of the fan set. Before commencing measurements and adjustments it is necessary to perform the following: Check if the air dampers at all grills and diffusers are set according to the design, Fresh air recirculation (if any) air dampers, should be set to one of extreme settings i.e. 100% fresh air or maximum recirculation, Measure the current taken by the fan s rotor. If it is necessary, choke the flow with the main choke or reduce the fan s rotary speed. Defining the volumetric air stream is based on measuring the average air flow velocity in the gauging section of the duct with the use of a Prandtl pipe and measuring the corresponding average dynamic pressure. Important factors influencing the accuracy of measurements include the following. The location of the gauging section in relation to elements, The number and location of gauge points in the gauge section, Quite stable and least interrupted air flow. It is especially inadvisable to locate the gauge section directly behind the following: Network elements that cause deformation of velocity field (elbows, reducers, T-connections, chokes, etc.), The fan where there can appear reverse velocities in the section. Measurements should be made on a duct segment with parallel walls and straight segments with the length of at least 6 diameters or equivalent diameters before the gauge point and not less than 3 diameters after it. In a real ventilation system finding such a long, straight segment can be difficult. In such a case you should 24

27 determine a gauge point in a place with lowest predicted disturbance of air flow and thicken the network of gauge points. The location of the gauge section should be determined at the stage of designing the system. Thorough recommendations concerning flow measurements and the location of gauge points are provided by ISO 5221 standard. The measured capacity is regarded appropriate if it is not different from the assumed one than ±10%. In case of higher disproportions it is possible to obtain capacity close to the designed one by means of the following: Adjustment of ventilation duct network, Changing the settings of the main air choke, Changing the fan s rotary velocity. While increasing the rotation speed of the fan, it is necessary to observe strictly the consumption of energy by the motor not to exceed the rated current value. It is also vital, due to strength reasons and permissible fan operation parameters, not to exceed the maximum rotor s speed value. In justified cases, the necessity of increasing the air capacity in relation to the measured value, increasing the rotary speed can involve changing the fan into a bigger one. In systems equipped with chokes automatically changing the proportion of fresh, circulation and exhaust air or the proportion of by-pass flow, capacity measurements and adjustments of the main choke should be performed at one of the extreme settings. Then, you should check the proportion or air and total capacity in the other extreme setting, and, if it is necessary, carry our appropriate adjustments in order to obtain proper proportions retaining fixed total capacity Adjusting the capacity of the thermal water heater Heater capacity control is performed after determining the appropriate amount of air flowing through an AHU. Adjustment of the heater s capacity consists in checking the effect of its operation from the air side by the air temperature measurements before and after the heater, with supply and return temperatures determined according to the design and the amount of the flowing heating medium. Heater capacity is adjusted by changing the water supply temperature. This is achieved by mixing supply water of high temperature with water at a lower temperature returning from the heater in a three-way valve. After mixing the heater supply water reaches appropriate temperature depending on the degree of mixing. External conditions close to the calculated ones appear in a yearly cycle within a relatively short period of time. In most cases, it is necessary to take into consideration adjustment in intermediate conditions for which appropriate recalculations into design parameters should be applied. Verifying the operation of the counter-freezing thermostat is only possible when the temperature of the air flowing on the exchanger is lower than the setting on the thermostat (default setting +5 o C). The safest way to perform the operation is when the temperature of the inflowing air is 1 2 degrees above 0. In such a case you should close the inflow of the heating medium for a while and check if the thermostat will work. These activities should be carried out before accepting a particular AHU for normal operation Elecric heater adjustments Adjustment of the electric heater s power is most often carried out by switching off individual groups of heating coils. In order to obtain multistage adjustment you should appropriately join individual heating coils. Smooth adjustment of the heater s power can be obtained through the application of appropriate automatics. It is necessary to perform a simulation of reduced power demand through decreasing the value of the set temperature so that all electrical stages (contactors) are OFF. Next you should increase the set value considerably and check if all electrical stages start in the order specified in the description of operation. Then go back to the initial temperature settings. 25

28 You should also check the operation of the protection securing against temperature increase in case there is no air flow. In order to achieve that you should reduce the stream of air flowing through the heater by closing the inlet air choke or reducing the fan s rotary speed During operation the speed of air flowing through the heater should not be lower than 1,5 m/s. You should pay attention to the fact that the risk of overheating increases along with reducing the air stream. Stopping the fan must be delayed (0,5-5 min) in order to cool down the heating coils of the heater Adjusting the capacity of the cooler. Adjustment of the cooler s capacity should be performed in conditions possibly closest to the rated ones. As in the case of the heater, the effect of operation from the air side is taken into consideration, by measuring relative temperatures and humidity before and after the cooler. In the process the temperature of the cooling agent must be monitored. If the effect of the cooler s operation is insufficient, it is necessary to carry out appropriate adjustment. Among others, it can be realized in the following ways: Adjustment of the amount of the cooling agent (water coolers), Adjustment of the amount of air flowing through an AHU (water coolers and with direct agent evaporation), Adjustment through changing the evaporation temperature (in systems with direct evaporation). Coolers usually operate in complex air conditioning systems equipped with automatic adjustment. Automatic adjustment devices should be checked not only in extreme rated conditions but also when they operate at incomplete cooler s workload. 8. OPERATION AND MAINTANCE People responsible for the operation of the AHU should familiarize with this manual before starting any operation and maintenance activities. In case there is no staff with sufficient technical skills any overhauls should be performed by Authorized VTS Service Center. Any damage to the AHU or its parts resulting from failing to observe instructions included in this documentation shall not be the subject of warranty repairs. AHU maintenance procedures should be performed on an inactive device. Careful and regular maintenance and monitoring technical condition of an AHU or its equipment is indispensable in order to detect damages at early stage before more serious damages occur. This documentation provides only basic instructions regarding control periods of time necessary for failure free operation of the AHU with a view to various external conditions of their operation and exploitation. Control periods must thus be adjusted to the existing conditions (pollution, number of start-ups, workload, etc.) AHU operators should make records in the Overhaul and Maintenance Works Table included in the Warranty card from the moment it is started. They should record all works resulting from normal, routine operation of the device. A carefully run record constitutes the only reliable document confirming the condition of the AHU s operation, times of running overhauls, observed inconsistencies in the unit s operation. In case it is necessary to contact VTS representatives you should use serial numbers of devices placed both on the cover and in the documentation provided with the AHU. Intervals between individual activities are specified on the assumption the AHU works non stop and in a system with low dustiness and no other conditions disturbing standard operation of the device. In environments characterised by high level of dustiness in the supply and/or exhaust controls should be carried out more frequently.. 26

29 Spare parts and accessories for AHUs should be ordered from the nearest Authorized VTS Service Center. While placing an order you should specify the type and serial number of a device. This information is provided on the rating plate placed on the fan section AIR DAMPERS Having observed increased level of dirt and heavy operation the air chore should be cleaned in one of the following ways: With the use of an industrial vacuum cleaner with a soft suction nozzle, Blow it through with the use of compressed air, Wash it with water under pressure with addition of some clearing agent not causing erosion to aluminium. Special attention should be paid to the tightness of the air choke after closing it, most importantly from the side of the outside air, or the water heater can freeze Filters At standard conditions of AHU s operation filters should be replaced more or less etery six months. The necessity is indicated (apart from Visual observation of their operation) by increased drop of pressure above the values specifies in table 13. AHUs can be equipped with the following type of filters. The filtration level is different for individual types of filters, that is why it is extremely important to insert filters with the same filtration class while replacing them. In case the final pressure difference on the filter exceeds the estimated value the filter should be replaced. P.FLT panel filters and B.FLT bag filters are designed for single use only. While replacing the filter you should also clean the filtration section by vacuuming of wiping it with a wet cloth. In case you order a new set of filters from an Authorized VTS Service Center you should specify the type of filter, filtration class and the size of an AHU, and optionally the size and amount of filters according to the list provided in the tables below. AHUs must always operate with fitted filters or the consumption of power by the fans may exceed the assumed values which may lead to burning the motor s winding. Tab.14. Bag filters applied in NVS AHUs AHU size Number of B.FLT bag filters with dimensions AxB for a single filtration section 592x x x x x592 NVS NVS NVS NVS L=300 for F5 class filters L=600 for F7 class filters 27

30 Tab.15. Panel filters applied in NVS AHUs AHU size Number of P.FLT G 4 filters for a single filtration section Dimension Amount AxB items NVS x290 1 NVS x430 1 NVS x513 1 NVS x Heat exchangers Water heater Water heaters, during operation, should be equipped with a counter-freezing system. Optionally, in the winter time, it is possibile to supply the heater with non-freezing agent (e.g. glycol solution). In case the inflow of the heating agent is stopped or there is a break in the AHU s operation and there is possibility of air temperature s dropping below + 5ºC the heater should be drained. In order to do that you should: Close the heating agent s inlet and outlet valves (cut the heater off from the heating system), Unscrew the drain and vent plug from the connection pins, Air wash the heater though with compressed air fed to the vent, At small time intervals repeat the procedure of airwashing several times until only air with no water drops comes out of the drain plug, Screw in the drain and vent plug. At least, every four months you should check for smudges of dirt on the heater s lamellae. Dust residue on the surface of the heater results in reducing the heating power of the heater and increasing the pressure drop on the air side. Even if the AHU is equipped with filters, dust sometimes settles on the heater s lamellae on the air supply side. Having observed excessive dirt you can perform cleaning using the following methods: With the use of a vacuum cleaner with a soft suction nozzle from the air intake side, Washing it with warm water with some detergents not causing corrosion to aluminium or copper. Before starting cleaning you should secure the adjacent AHU sections against the released dirt. In order to obtain full thermal capacity the heater must be well vented. You can use vent plugs located in the connection pins of the heater for this purpose. During stoppages of the AHU the flow of the heating agent should be limited to the minimum so that the temperature inside the device does not exceed + 60ºC. Exceeding that value may result in damaging some elements or subcomponents (motor, bearings, plastic elements, etc.) assembled in sections adjacent to the heater. 28

31 Electric heater The heater s battery consists of uncovered heating coils. During AHU s operation, when the heater is inactive, dust can settle on the heating coils. When the heater is activated heavy dirt can result in the smell of burnt dust and even cause fire hazard. At equal time intervals (every 4 months), especially before the heating season, you should check the electrical connections and the technical condition of the heating elements for deformations or dirt. Any smudge of dirt should be removed with the use of a vacuum cleaner with a soft suction nozzle or air washed with compressed air. Cleaning electric heaters with water is forbidden! NYou should also check the operation of the protection against temperature increase in case there is no air flow. The air velocity should not drop below 1,5 m/s Water or glycol cooler The cooler should be checked for dirt every four months. If necessary the cooler can be cleaned in the same way as the heater. Before starting cleaning you should secure the adjacent ANU sections. While inspecting the AHU for dirt, you should also check the cleanliness of the condenser and the passability of the outflow from the drip pan as well as the passability of the water seal. The water seal should be flooded before starting the AHU. If the condenser is dirty it should be washed with hot water with some detergents. Additionally in the case of the glycol cooler you should check the content and the density of glycol in the circulation. In order to achieve full thermal capacity the cooler must be well vented. You can use vent plugs placed in the cooler s connection pins for that purpose Freon cooler Operation of the freon cooler covers the same scope of activities as for the water heater and cooler. While washing the freon cooler with warm water you should drain the cooling system by draining freon to a tank. Otherwise there is high risk of uncontrolled increase of Freon pressure and damaging the cooling system Silencing section The silencing section consists of curtains filled with non-flammable mineral wool absorbing acoustic energy fitted in a ventilation duct. Maintenance works consist in checking the silencing curtains for dirt and, if needed, clearing them Fan set Before starting any works (breakdown, maintenance, service) with the AHU, and especially before opening covers from live elements, you should make sure if: The device has been appropriately unplugged. If refers to both main and supplementary circuits, The rotor is idle, The fan has cooled down and the surface temperature is low enough not to cause burns, The fan is secured against accidental start-up 29

32 Fans The fans are designed for transporting dust-free or lightly dusted air. They are not designed for aggressive gases, steams and heavily dusted air. The operation of the fan in inappropriate conditions can result in damaging bearings, corrosion, unbalanced rotor and vibrations. The fan and the driver motor in the set are adjusted for specific AHU operation parameters defined in the design. The rotary speed of the fan is adjusted so as the air stream and the fan s total swell effect is appropriate for the cooperating ventilation system. Reduced stream of air forced through means disturbance of appropriate operation and leads to upsetting the balance of the entire ventilation system. It can also be a result of the following: Inappropriate settings of the rotary speed Higher than assumed pressure drop in the system Inappropriate direction of the fan s rotation. If the fan is radiator fan is turning in a wrong direction the capacity of air flow is considerable lower. In case of performing servicing of the fan (from the side of the AHU s outlet) you should check if: The rotor is turning smoothly, There is no whipping, The rotor is well mounted on the axle, It has not moved in relation to the intake funnel, All mounting screws of the fan set are tightened. An unbalanced rotor can be a result of the following: Dust residues on the rotor s plates, Tearing off additional balancing weights, Damaging the rotor s plates. You should check the casing inside, the rotor and the motor for dirt every 4 months and, if needed, clean the following: The casing s inside with the use of a vacuum cleaner, The rotor with the use of a vacuum cleaner or with water and some mild detergent Motors Careful and regular maintenance works as well as controls of the motor s condition are indispensable for detecting damages before serious damages occur. Before commencing any works connected with the motor or any other element of the motor s equipment, especially before removing the covers protecting from direct contact with moving elements or elements that may be live, the motor should be switched off from the source of power supply appropriately. Moreover, all additional and supplementary circuits should also be disconnected. It is necessary to observe the following safety rules: Disconnect power supply, Apply the protection from accidental start-up. The safety measures specified above should be taken until all maintenance works have been completed and the motor has been fully assembled and is ready for start-up. 30

33 MOTOR BEARINGS As standard motors are equipped with 62 series ball bearings with the cover. Tab.16. List of motor bearings 8.6. Control measurements Mechanical size of the motor Bearing from the drive s side Bearing at the rear of the motor 71M Z-C Z-C3 80M Z-C Z-C3 90L Z-C Z-C3 112M Z-C Z-C3 After carried out overhauls and maintenance works you should perform an inspection and adjustment of the AHU s operation parameters in accordance with recommendations included in point 7. The fact of performing any maintenance works and control measurements must be recorded in the Table of overhauls and maintenance works. 9. INDUSTRIAL SAFETY MANUAL 1. AHU connection and start-up should be performed by qualified staff in conditions in accordance with valid rules and regulations especially in the field of electrical device operation. 2. It is forbidden to switch on the network s power supply before connecting the AHU to the protection system. 3. It is forbidden to carry out reparation and maintenance works without prior switching of the AHU s power supply. 4. AHU operation with removed inspection panels of any of the AHU s sections is strictly forbidden. 5. A person servicing, performing repairs or maintenance works must possess appropriate qualifications and authorization resulting from rules and regulations valid in the territory of the country where the particular AHU is fitted. 6. Place of fitting an AHU must be equipped with indispensable protection equipment ensuring safe operation as well as necessary fire prevention equipment resulting from local rules and regulations. 10. INFORMATION Periodic overhauls carried out by qualified technical staff or Authorized VTS Service Centers guarantee failure free and reliable operation for many years. At any time service workers are ready to participate in AHU start-ups, maintenance Works and remain at your disposal in any emergency situation Authorized VTS Service Centers also sell spare parts and exploitation materials for AHUs. While placing an order you should specify the type and the size of an AHU as well as its serial number. Information concerning the network of service companies is available at our internet website at 31