T8400, T840 and T844,D Electronic Thermostats PODUT DATA APPLIATION T8400 and T840 T844,D The T8400 and T840 Standard Electronic Thermostats provide single-stage, non-programmable temperature control for 4V heating-cooling systems with manual changeover from heat to cool. The T844 Electronic Multistage Thermostat provides twostage heat and one-stage cool control. The T844D Electronic Multistage Thermostat provides twostage heat and two-stage cool control. FEATUES Attractive styling complements any decor to the homeowner s delight. Ease-of-use means fewer homeowner questions and increased homeowner satisfaction. Large display for quick easy readability. onveniently sized 3-/ x 3-/ thermostat with optional decorator cover plates (3-7/8 in. x 3-7/8 in. and 5-3/4 in. x 5-3/4 in.) makes it easy to install in a variety of locations. Keys are located for easy access. Fan and system switches are located on the lower edge to eliminate accidental setting changes. Easy installation, setup and self-test saves time and increases installer productivity. Manual changeover from heat to cool eliminates unexpected system operation. F or temperature display for added model flexibility. Selectable heating cycle rate (, 3, 4, 5, 6 or 9, cph) for a variety of applications which reduces the amount of inventory. ooling cycle rate is fixed (3 cph), the standard setting for compressors, for speedy installation. Setpoints are permanently held in memory (no batteries used) and retained during power outages for increased installer and homeowner convenience. Power stealing and hard wired models available for virtually all equipment and application needs including gravity or radiating systems, hydronic heat, condensing gas furnaces, gas or oil forced air and electric heat. ontents Application... Features... Specifications... Ordering Information... Installation... 3 Settings and Adjustments... 8 Operation... 0 heckout... Troubleshooting... 3 U.S. egistered Trademark opyright 00 Honeywell All ights eserved 68-080- 3
T8400, T840 AND T844,D ELETONI THEMOSTATS SPEIFIATIONS IMPOTANT The specifications given in this publication do not include normal manufacturing tolerances; therefore, an individual unit might not exactly match the listed specifications. Also, this product is tested and calibrated under closely controlled conditions, and some minor differences in performance can be expected if those conditions are changed. T8400, T840, T844,D TADELINE models include a thermostat, wallplate for wiring and mounting thermostat and owner s guide. T8400, T840 SUPE TADELINE models include a thermostat, wallplate (for mounting and wiring thermostat), two decorator cover plates for covering wall marks (3-7/8 in. x 3-7/8 in. and 5-3/4 in x 5-3/4 in.), and owner s guide. Power: T8400: 4 Vac nominal, 8 to 30 Vac, 50/60 Hz. T840: 4 Vac nominal, 8 to 30 Vac, 50/60 Hz. T844,D: 4 Vac nominal, 8 to 30 Vac, 50/60 Hz. Electrical atings: Heating:.0 to.5a run; 3.5A inrush. ooling:.0 to.5a run; 7.5A inrush. Fan:.0 to 0.5A run;.5a inrush. urrent Draw: T8400 Power Stealing Thermostat requires less than 0.5 ma current draw when the thermostat calls for heat and is compatible with most 4V microprocessor systems. The T8400 Power Stealing Thermostat can be used in any non-millivolt application where the T840 and T844,D Hard ired Thermostats cannot be used. For further detail, see Power Stealing in the Operation section. Temperature Adjustment: Setpoint temperature is adjusted by using the or keys. One press changes the setpoint one degree; pressing and holding changes the setpoint several degrees. Temperature Setting ange: 40 F (4 ) to 99 F (37 ). Ambient Temperature ange: 40 F (4 ) to 0 F (43 ). Shipping Temperature ange: -0 F (-9 ) to 0 F (49 ). Operating elative Humidity: 5% to 90% H, noncondensing. ycle ates (at 50% Load): Heating: Selectable at, 3, 4, 5, 6, 9 or cph. See Table for cycle rate options and corresponding system equipment. ooling: Fixed at 3 cph. Table. Heating ycle ates. System ycles Per Hour Steam, gravity Hydronic heat, condensing 3 gas furnaces a Special applications b 4, 5 as or oil forced air (default) 6 Electric heat 9 Special applications b a High efficiency furnace. b efer to equipment manufacturer s instructions. Finish: T8400, T840 and T844,D TADELINE AND SUPE TADELINE : Taupe finish. T8400, T840 and T844,D STANDAD MODELS: Premier hite finish and only available in builder packs of 0. Accessory: Decorator cover plates (for covering wall marks): 5-3/4 in. x 5-3/4 in. and 3-7/8 in. x 3-7/8 in. Dimensions: See Fig. or. ODEIN INFOMATION hen purchasing replacement and modernization products from your TADELINE wholesaler or distributor, refer to the TADELINE atalog or price sheets for complete ordering number. If you have additional questions, need further information, or would like to comment on our products or services, please write or phone:. our local Home and Building ontrol Sales Office (check white pages of your phone directory).. Home and Building ontrol ustomer elations Honeywell, 985 Douglas Drive North olden Valley, Minnesota 554 (800) 468-50 In anada Honeywell Limited/Honeywell Limitée, 35 Dynamic Drive, Scarborough, Ontario MV 4Z9. International Sales and Service Offices in all principal cities of the world. Manufacturing in Australia, anada, Finland, France, ermany, Japan, Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A. 68-080-3
T8400, T840 AND T844,D ELETONI THEMOSTATS ALLPLATE THEMOSTAT THEMOSTAT AND ALLPLATE -7/8 (78) 3-/ (89) -3/6 (55) -/ (64) UP -/ (37) -7/8 (78) 3-/ (89) Set oom Auto On SSTEM ool Off Heat M083A ALLPLATE 4-3/8 () 3-5/6 (84) Fig.. T8400/T840 Thermostat dimensions in in. (mm). -3/8 (70) THEMOSTAT THEMOSTAT AND ALLPLATE 5-/ (40) -3/6 (55) INSTALLATION hen Installing this Product. ead these instructions carefully. Failure to follow them could damage the product or cause a hazardous condition.. heck the ratings given in the instructions and on the product to make sure the product is suitable for your application. 3. Installer must be a trained, experienced service technician. 4. After installation is complete, check out product operation as provided in these instructions. AUTION Disconnect power supply before beginning wiring to prevent electrical shock or equipment damage. Auto On Set oom SSTEM ool Off Heat Em. Ht. 3-/ (89) MEU NOTIE If this control is replacing a control that contains mercury in a sealed tube, do not place your old control in the trash. Dispose of it properly. Fig.. T844 Thermostat dimensions in in. (mm). M8585 ontact your local waste management authority for instructions regarding recycling and the proper disposal of the control. If you have questions, call the Honeywell ustomer esponse enter at -800-468-50. 3 68-080-3
T8400, T840 AND T844,D ELETONI THEMOSTATS Location Install the thermostat about 5 ft (.5m ) above the floor in an area with good air circulation at average temperature. See Fig. 3. Do not install the thermostat where it can be affected by: drafts or dead spots behind doors and in corners. hot or cold air from ducts. radiant heat from the sun or appliances. concealed pipes and chimneys. unheated (uncooled) areas such as an outside wall behind the thermostat. ES NO NO 5 FEET [.5 METES] NO M0308 Fig. 3. Typical location of thermostat. Mounting Decorator over Plate and allplate to all IMPOTANT Level for appearance only. The thermostat functions normally even when not mounted level. 5-3/4 IN. x 5-3/4 IN. DEOATO OVE PLATE ALL NOTE: The TADELINE models include a thermostat and wallplate (for wiring and mounting thermostat). T8400, T840 SUPE TADELINE models include a thermostat, wallplate (for wiring and mounting thermostat) and two decorator cover plates (for covering wall marks). ALL ANHOS () Mount decorator cover plate (SUPE TADELINE model only), wallplate, T8400, T840 or T844,D, and the screws provided (see Fig. 4 or 5) as follows:. Place the desired decorator cover plate and the wallplate at the desired location on the wall.. Pull the thermostat wire through the entrance hole on the decorator cover plate, then through the wallplate entrance hole. 3. Select the two mounting holes that best fit the application. 4. Fasten the decorator cover plate and the wallplate to the wall using the screws provided. 5. After wiring the wallplate, plug the hole to prevent drafts from affecting the thermostat; see iring section. 3-7/8 IN. x 3-7/8 IN. DEOATO OVE PLATE (SELET MODELS). DILL 3/6 INH HOLES (IF DALL) O 7/3 (PLASTE O OOD) HEN USIN ALL ANHOS. M04 Fig. 4. Mounting the T8400 and T840 decorator cover plate and wallplate to wall. 68-080-3 4
T8400, T840 AND T844,D ELETONI THEMOSTATS ALL ALL ANHOS () KEEP IIN IN SHADED AEA MOUNTIN SES () ALLPLATE B HEN USIN ALL ANHOS, DILL 3/6 INH HOLES FO DALL, 7/3 INH HOLES FO PLASTE O OOD. M0A O Fig. 5. Mounting the T844 wallplate to wall. iring MOUNTIN SE HOLE IIN ENTANE HOLE MOUNTIN SE HOLE IMPOTANT Use an 8-gauge maximum wire for wiring the thermostats. All wiring must comply with local electrical codes and ordinances. Disconnect the power supply to prevent electrical shock or equipment damage. NOTE: To ensure proper mounting of thermostat, restrict all wiring to the shaded area on the left side of the terminals. See Fig. 6 or 7. M0 KEEP IIN IN SHADED AEA ALTENATE MOUNTIN SE HOLE Fig. 7. estrict T844 wiring to shaded area. The shape of the terminals permits insertion of straight or wraparound wiring connections; either method is acceptable. See Fig. 8 or 9. MOUNTIN SE HOLE ALTENATE MOUNTIN SE HOLE IIN ENTANE HOLE FO APAOUND STIP 7/6 IN. ( MM) MOUNTIN SE HOLE M03 Fig. 6. estrict T8400 and T840 wiring to shaded area. FO STAIHT INSETION STIP 5/6 IN. (8 MM) TEMINAL SE M3 Fig. 8. T8400 and T840 wiring connections. 5 68-080-3
T8400, T840 AND T844,D ELETONI THEMOSTATS TEMINAL SE FO STAIHT INSETION STIP 5/6 IN. (8 MM) FO APAOUND STIP 7/6 IN. ( MM) T8400, T840 ELA OOLIN ONTATO B L (HOT) L 4V L (HOT) L OIL PIMA ONTOL POE SUPPL. POVIDE DISONNET MEANS AND OVELOAD POTETION AS EQUIED. T T O M0 IN T840 INSTALLATIONS, ONNET TEMINAL. M0B Fig.. T8400/T840 heat-cool wiring diagram in oil heating/electric cooling system. Oil primary has its own transformer. Fig. 9. T844 wiring connections. The T8400 Thermostats steal power through the heating and cooling system controls and are adaptable to most 4-wire, 8 to 30 Vac heating-cooling systems. The T840 and T844,D Thermostats are powered directly from the system transformer and are adaptable to most 5-wire, 8 to 30 Vac heating-cooling systems. efer to Fig. 0 through 4 for typical wiring hookups. T8400, T840 T844 STAE-ONE HEATIN ST STAE OOLIN ND STAE OOLIN OOLIN ONTATO L (HOT) L 4V STAE-TO HEATIN ELA L (HOT) L 4V HEATIN PIMA ONTOL ELA POE SUPPL. POVIDE DISONNET MEANS AND OVELOAD POTETION AS EQUIED. M03 Fig.. T844,D two-stage heat and two-stage cool system with manual changeover wiring diagram. POE SUPPL. POVIDE DISONNET MEANS AND OVELOAD POTETION AS EQUIED. IN T840 INSTALLATIONS, ONNET TEMINAL. M0B Fig. 0. T8400/T840 heat-cool wiring diagram in single transformer system with gas heat/electric cooling. 68-080-3 6
T8400, T840 AND T844,D ELETONI THEMOSTATS ZONE T8400, T840 ZONE T8400, T840 ZONE 3 T8400, T840 ZONE 4 T8400, T840 4 4 4 4 839A05 8B067 8B067 8B067 L L (HOT) ZONE VALVE O DAMPE MOTO 3 3 3 ZONE 3 ZONE 4 VALVE O VALVE O DAMPE DAMPE MOTO MOTO ZONE VALVE O DAMPE MOTO 3 POE SUPPL. POVIDE DISONNET MEANS AND OVELOAD POTETION AS EQUIED. USE ONE 839 FO EVE FOU ZONES. 3 USE FO 3-IE ZONE VALVE O DAMPE. 4 IN T840 INSTALLATIONS, ONNET TEMINAL. M085A Fig. 3. T8400/T840 heat only wiring diagram for controlling incompatible or 3-wire zone valves or dampers. Heating equipment is operated by end switch on the zone valve or motor, or by thermostat in master zone. T8400, T840 6 D89/M89 4 9756A ABLE 4 L848E65 4 TV T 3 Z K 3 FUSE HIH LIMIT ONTOLLE 3 B K 5 POLAIZED 4-PON MALE MOLEX PLU AND 4-PON FEMALE MATIN PLU ON ABLE 6-PON FEMALE MOLEX EEPTABLE IN L848E AND 5-PON MALE MOLEX PLU ON ABLE K B B L 5 L IULATO POE SUPPL. POVIDE DISONNET MEANS AND OVELOAD POTETION AS EQUIED. S860 L (HOT) L 3 EMOVE PLU-IN THAT JUMPES PINS AND 3 HEN USIN VENT DAMPE. AFTE VENT DAMPE IS PLUED INTO L848E65, FUSE BLOS HEN THEMOSTAT FIST LOSES. AFTE FUSE BLOS, L848E65 OPEATES ONL HEN VENT DAMPE IS ONNETED. 4V ND 4V 4 SEE VENT DAMPE PODUT SPEIFIATIONS FO INTENAL SHEMATIS. 5 B IS /4 IN. TAB TEMINAL. 6 IN T840 INSTALLATIONS, ONNET TEMINAL. M086 Fig. 4. T8400/T840 heat only wiring diagram with L848E65 (with internal plug) wired directly to vent damper in hydronic intermittent pilot system. 7 68-080-3
T8400, T840 AND T844,D ELETONI THEMOSTATS Mounting Thermostat to allplate. Engage the tabs at the top of the thermostat and wallplate.. Swing down the thermostat and press the lower edge of the thermostat onto the wallplate to latch. See Fig. 0. DASHED LINES INDIATE TABS ON BAK OF THEMOSTAT SETTINS AND ADJUSTMENTS Setting Fan and System Switches Fan and system settings are controlled manually using the switches located at the bottom of the thermostat case. See Fig. 7 or 8. TEMPEATUE DISPLA Set oom Set oom INEASE SETTIN Auto On SSTEM ool Off Heat Auto SSTEM ool Off Heat A ENAE TABS AT TOP OF THEMOSTAT ITH SLOTS ON ALLPLATE. Set oom DEEASE SETTIN M05B B PESS LOE EDE OF ASE TO LATH. Fig. 5. Mounting T8400 or T840 thermostat to wallplate. DASHED LINES INDIATE TABS ON BAK OF THEMOSTAT Auto On SITH SSTEM ool Off Heat SSTEM SITH M00A Fig. 7. T8400 and T840 temperature display and system switches. TEMPEATUE DISPLA INEASE SETTIN DEEASE SETTIN Auto On SSTEM ool Off Heat A ENAE TABS AT TOP OF THEMOSTAT ITH SLOTS ON MOUNTIN PLATE. Auto On SITH SSTEM ool Off Heat SSTEM SITH M4678 Auto On B SSTEM ool Off Heat PESS LOE EDE OF ASE TO LATH. M4677 Fig. 8. T844 temperature display and system switches. Fan Switch Fan switch settings are: ON: The fan runs continuously. Use for improved air circulation. AUTO: Normal setting for most homes. In cooling, the fan starts and stops with the cooling equipment. In heating, the fan is controlled directly by the heating equipment and may start a few minutes after the heating equipment turns on (on Fig. 6. Mounting T844 thermostat to wallplate. 68-080-3 8
T8400, T840 AND T844,D ELETONI THEMOSTATS most systems). hen using an electric heat thermostat, the fan starts and stops with the heating equipment. Slide the switch in the bottom left corner of the thermostat to select the desired fan setting. System Switch System switch settings control thermostat operation as follows: OOL: The thermostat controls the cooling system. HEAT: The thermostat controls the heating system. OFF: Both heating and cooling are off. Slide the switch in the bottom right corner of the thermostat to select the desired system setting. Set Temperature Setpoint NOTE: Temperature setpoint range is 40 to 99 F (4 to 37 ). The temperature setpoint and the room temperature are shown separately on the display. The indicator points to Set when the temperature setpoint is displayed and to oom when the room temperature is displayed. To set the temperature setpoint:. Select Heat or ool by sliding the system switch in the lower right corner of the thermostat to the desired mode. See Fig. 7 or 8.. To display the selected temperature setpoint on the digital display, press either the or key once. The temperature setpoint is displayed for approximately five seconds as the M4680 indicator points to Set and flashes. 3. To increase the temperature setpoint press the key. Each press changes the setpoint one degree; press and hold to change the setpoint several degrees. M468 4. To decrease the setpoint temperature press the key. Each press changes the setpoint one degree; press and hold to change the setpoint several degrees. M468 Setting F/ Indication and Heat ycle ate NOTE: Set oom INDIATO OOM TEMPEATUE SETPOINT TEMPEATUE M47 To save changes to the F/ indication and the heat cycle rate, all seven steps must be completed. To set the F/ indication and heat cycle rate:. If the room temperature is displayed in F, set the temperature setpoint to 5 F. If the room temperature is displayed in, set the temperature setpoint to.. Press the and keys simultaneously for more than one second to light all segments on display and to enter installer setup mode. hen the keys are released, a two-digit software code is displayed. Optional System heckout hen in steps B and only, the key can be used to turn heat or cool outputs on and off. hange the system switch setting to test heat or cool outputs. No action takes place If the system is in the Off position. EXAMPLES: System setting at HEAT: If heat is on, the key turns it off; if heat is off, turns it on. System setting at OOL: If cool is on, key turns it off; if cool is off, turns it on. NOTE: In installer setup mode only, each press of the key momentarily displays 0 and each press of the key momentarily displays 0. hen the keys are released, these two-digit codes are no longer displayed. 3. Press the key. Factory information is displayed. A typical example is shown, but information displayed varies by model. This information is for factory use only. 4. Press the key again to display or F. 5. Press the key to change the or F indication. NOTE: Steps 6 through 9 apply only to T844 Thermostats. 6. Press key to display number of cooling stages. 7. Press key to change the number of cooling stages. 8. Press key to display the number of heating stages. 9. Press key to change the number of heating stages. M4683 M4686 M4684 M4685 M4687 M4688 M4689 M008 M007 M009 M00 9 68-080-3
T8400, T840 AND T844,D ELETONI THEMOSTATS 0. Press the key to display the heat cycle rate of, 3, 4, 5, 6, 9 or. hen set at two stages of heat (T804 only), both stages operate at selected cycle rate. If the desired M030 cycle is displayed, press the key to exit the installer setup mode. To change the heat cycle rate, press the key to scroll between cycle rates. Stop scrolling when the desired rate is displayed. See Table for the cycle rate options and the corresponding system equipment. Table. Heating ycle ates. System ycles Per Hour Steam, gravity Hydronic heat, condensing 3 gas furnaces a Special applications b 4, 5 as or oil forced air (default) 6 Electric heat 9 Special applications b a High efficiency furnace. b efer to equipment manufacturer s instructions.. Press the key to display algorithm configuration.. Press the key again to change the algorithm to or 3. = standard algorithm. 3 = aggressive algorithm (can cause overshooting). 3. Press the key again. urrent algorithm () is displayed. A typical example is shown, but varies by model. This information is for factory use only. 4. Press the key to save all changes, exit installer setup mode and return to normal operation. NOTE: After exiting installer setup mode, change the setpoint to the desired room temperature. M849 M840 OPEATION The T8400 and T840 Standard Electronic Thermostats provide single-stage temperature control using proportional plus integral (P+I) control to eliminate droop. The T844 provides two-stage heat and two-stage cool temperature control with P+I control. The T844D Electronic Multistage Thermostat provides two-stage heat and two-stage cool temperature control and also uses P+I control. Zero Droop Performance The thermostats control temperature closer to setpoint than electromechanical thermostats. This is because proportional plus integral control maintains the same indoor temperature independent of the outdoor temperature. Thus the T8400 and T840 Thermostats provide tight temperature control with virtually no noticeable swings in temperature setpoint, a condition referred to as droop. This zero droop performance provides improved occupancy comfort. Occupants do not need to continually adjust thermostat settings to be comfortable, even during severe weather. Electromechanical thermostats have little control over droop, thus resulting in room temperature changes of 3 F to 5 F as outdoor temperature varies. Power Stealing Unlike hard wired thermostats which are powered directly from the system transformer, the T8400 Thermostat steals power through the heating and cooling system controls and can be used in applications where existing wiring does not permit using hard wired thermostats. See Fig. 9 and 0. Previous Honeywell power stealing thermostats required 80 ma of load current when the heating and cooling was on. The T8400 Thermostat requires only.5 ma of load current (/3 of previous models) when the heating or cooling is on. hen the heating or cooling is off, the thermostat operates at 0. ma (/00 of previous models). Other Honeywell power stealing thermostats are available, but they have different powering requirements than the T8400. This low current draw makes the T8400 applicable to most 4V heating and cooling systems. The T8400, T840 and T844,D Thermostats only operate when mounted on the wallplate with 4V applied. Batteries are not required for operation because temperature setpoints and configuration settings are retained permanently in memory. 68-080-3 0
T8400, T840 AND T844,D ELETONI THEMOSTATS L (HOT) L THEMISTO SENSO THEMOSTAT LOI SITH ON AUTO ELA SSTEM SITH HEAT HEAT ELA OFF OOL OOL ELA POE SUPPL LOI AND ONTOL MOSFET POE SUPPL. POVIDE DISONNET MEANS AND OVELOAD POTETION AS EQUIED. MOSFET M0360 Fig. 9. T8400 power 0stealing internal schematic. SITH ON AUTO ELA THEMISTO SENSO ELA L (HOT) L THEMOSTAT LOI SSTEM SITH HEAT HEAT ELA POE SUPPL OFF OOL ELA OOL POE SUPPL. POVIDE DISONNET MEANS AND OVELOAD POTETION AS EQUIED. M09 Fig. 0. T840 hardwired internal schematic. Energy Savings ou can save energy with the T8400, T840 and T844,D Thermostats in the heating mode by lowering the temperature setting 5 F (3 ) to 0 F (5 ) at night and during the day. ou can also save energy in the cooling mode by raising the temperature setting during the day before you leave for work or school. Savings can be as high as 7% to 33% depending on your home, where you live, the number of energy saving periods you choose and your energy savings temperature settings. efer to the maps in the Operation section for typical energy savings. Sequence of Operations The Fan, Heat and ool outputs are relay or mosfet controlled. A loss of ac power or a change in the SSTEM switch setting can cause the outputs to turn off. The truth table shows the sequence of operations for the settings and SSTEM modes. See Table 3 Sequence of Operations. 68-080-3
T8400, T840 AND T844,D ELETONI THEMOSTATS Table 3. Sequence of Operations. Switch Settings SSTEM Switch Settings all for Action Energize Terminals Display Icons Auto Off None None None On Any Any None Auto ool ooling, Auto Heat Heating a,b a In electric heat models, and are energized with calls for heat. b and terminals are energized in the T844,D models. Fan ontrol The switch settings are On and Auto. ON:The fan runs continuously. AUTO:In cooling, the fan starts and stops with the cooling equipment. In heating, the fan starts a few minutes after the heating equipment turns on. hen using an electric heat thermostat, the fan starts and stops with the heating equipment. Heat Mode ith the SSTEM switch at Heat, the thermostat controls the heating system. On a call for heat, the terminal is energized and a flame is shown on the digital display. ool Mode ith the SSTEM switch at ool, the thermostat controls the cooling system. On a call for cool, the and terminals are energized and a snowflake is shown on the digital display. Minimum Off-Timer A minimum off-timer in the T8400, T840 and T844,D assures that the cooling compressor does not come on again for at least five minutes after it turns off. The minimum-off timer is triggered when the compressor turns off and when the system switch is changed. If the compressor turns off when the setpoint is changed, then the minimum-off timer is triggered. Power interruption and power restoration also trigger the minimum off-timer. The minimum-off timer operates only during the cooling cycle on the thermostat. HEKOUT Heating. Slide the system switch to Heat and the fan switch to Auto.. Press and hold the key to raise the temperature setting several degrees above the room temperature. After approximately ten seconds the terminal is energized and the heating equipment starts. 3. Press the key to lower the temperature setting below the room temperature. Heating equipment should stop. ooling AUTION Low Temperature Hazard. Operating at too low of an outdoor temperature can cause compressor damage. Do not operate cooling if outdoor temperature is below 50 F (0 ). efer to manufacturer recommendations. To avoid compressor damage, allow the compressor to remain off for five minutes before restarting.. Slide the system switch to ool and the fan switch to Auto.. Press the key to lower the temperature setting several degrees below the room temperature. After approximately five minutes the and terminals are energized and the cooling equipment starts. 3. Press the key to raise the temperature setting above the room temperature. ooling system should shut down. Fan. Slide the SSTEM switch to Off and the switch to On. The fan should run continuously.. Slide the switch to Auto. In heating, the fan is controlled directly by the heating equipment and may start a few minutes after the heating equipment turns on (on most systems). hen using an electric heat thermostat, the fan starts and stops with the heating equipment. In cooling, the fan starts and stops with the cooling equipment. Make certain all equipment responds properly to the thermostat. 68-080-3
T8400, T840 AND T844,D ELETONI THEMOSTATS TOUBLESHOOTIN efer to Fig. for the proper troubleshooting procedure. SMPTOM POSSIBLE AUSE ATION HEATIN O OOLIN EQUIPMENT ON'T OPEATE. NO A POE TO THEMOSTAT. HEK THAT TEMINAL IS ONNETED TO THE SSTEM TANSFOME. HEK POE TO HEATIN AND OOLIN EQUIPMENT ON-OFF SITH FUSE O IUIT BEAKE LOOSE 4V ONNETION AT THEMOSTAT AT FUNAE/AI ONDITIONE INOET IIN (SEE IIN DIAAM) THEMOSTAT INOPEATIVE. ONDUT SELF-TEST; SEE HEKOUT SETION. PESENT SETTIN TOO LO/HIH. ADJUST TEMPEATUE B PESSIN O KES. SSTEM SITH ON THEMOSTAT IN ON POSITION. ESET THEMOSTAT SSTEM SITH. MINIMUM-OFF TIMES IN THEMOSTAT IN OPEATION ON OOLIN O FIST STAE HEATIN. AIT FIVE MINUTES O FOLLO STEPS IN HEKOUT SETION. INOET IIN. HEK IIN DIAAM. HEATIN O OOLIN EQUIPMENT INOPEATIVE. ONSULT EQUIPMENT MANUFATUE INSTUTIONS. PATIAL DISPLA INOPEATIVE THEMOSTAT. EPLAE THEMOSTAT. STILL IN INSTALLE SETUP MODE. SEE THE SETTINS AND ADJUSTMENTS SETION FO INSTUTIONS ON INSTALLE SETUP MODE. NO DISPLA NO POE TO THEMOSTAT. HEK THAT TEMINAL IS ONNETED TO THE SSTEM TANSFOME. HEK POE TO HEATIN AND OOLIN EQUIPMENT ON-OFF SITH FUSE O IUIT BEAKE LOOSE 4V ONNETION AT THEMOSTAT AT FUNAE/AI ONDITIONE INOET IIN (SEE IIN DIAAM) THEMOSTAT MOUNTED INOETL ON ALLPLATE. SEE INSTALLATION INSTUTIONS FO OET MOUNTIN. TEMPEATUE DISPLA IS INOET. THEMOSTAT IS ONFIUED FO F O DISPLA. EONFIUE THE DISPLA. SEE SETTINS AND ADJUSTMENTS SETION. TEMPEATUE SETTINS ILL NOT HANE. (EX: ANNOT SET THE HEATIN HIHE O THE OOLIN LOE). THE UPPE O LOE TEMPEATUE LIMITS EE EAHED. HEK THE TEMPEATUE SETPOINTS; TEMPEATUE SETTIN ANE IS 40 F (4 ) TO 99 F (37 ). DOES NOT OPEATE POPEL IN HEAT O OOL MODES. INOET IIN. HEATIN O OOLIN EQUIPMENT INOPEATIVE. HEK IIN DIAAM. ONSULT EQUIPMENT MANUFATUE INSTUTIONS. M09B Fig.. Troubleshooting procedure. 3 68-080-3
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