Troubleshooting the Indoor AHU as a Standard Product

Indoor Unit Circuit Board

Indoor Unit Circuit Board Schematic

The TECHs Need to Understand the Status and Fault Codes by LED Lights The control board includes an LED that displays status and fault codes. The control will display the fault codes until power is removed from the control or the fault condition is no longer present.

The TECHS Must Be Sure of AIRFLOW SELECTION The airflow and comfort setting selection jumpers must be set properly at the time of installation for proper system operation. NOTE: Incorrect airflow and comfort settings may result in decreased system efficiency and performance.

DB entering air temperature Nominal Air Flow Chart Leaving Air Temp. Evaporator Leaving Air Temperature (DB) Wet bulb entering air temperature 57 58 59 60 61 62 63 64 65 66 67 68 69 70 70 51 51 52 52 53 53 54 55 55 56 57 58 59 60 72 52 52 53 54 55 55 56 57 57 58 59 60 61 62 74 53 53 53 54 55 55 56 57 58 58 59 60 61 62 76 54 54 54 55 55 56 57 57 58 59 60 61 62 63 78 55 55 55 56 56 57 57 58 59 60 61 62 63 64 80 56 56 56 57 57 58 58 58 60 61 62 63 64 65 Find evaporator entering air dry bulb temperature Find evaporator entering air wet bulb temperature Provides evaporator leaving air dry bulb temperature If not within +/- 3 F, adjust fan speed

The Outdoor Equipment-ACHP Unit

CONTROL ERROR CODES On Outdoor Units In the event of a failure in the outdoor unit, the control has a built in diagnostic LED for troubleshooting purposes. Figure below shows the location of the diagnostic LED on the ACHP control board. During normal operation this LED fades on, and blinks off continuously. If for any reason the unit has encountered an error condition, the error may be diagnosed using the error table below.

Troubleshooting the Outdoor Unit Know What is the Sequence of Operation Remember to always test for Proper Volts and Run Load Amps

Outdoor Unit Circuit Board Standard Equipment

Outdoor Unit Circuit Board

Line Voltage Components

Indoor-Outdoor Data Loggers

Review of WVC ACHP Recorded Performance Data from local Electric Utility

WVC College Outdoor Units

What We Know About Furnaces

Gas Furnace Technology Has Evolved AFUE Ratings Older 70-80% Newer 80-90% Modern 90%+ Higher AFUE Rated Furnaces Save Money AFUE is the Annual Fuel Usage Efficiency

AFUE Potential Savings Comparisons

Where are We Going With Furnaces? Guide to High-efficiency Gas Furnaces 90% to 98% AFUE Ratings ECM Motors 5-10 Year Warranties 2 Stage Gas Valves Modulating Gas Valves All Electronic Controls Intelligent Thermostats (web based) Smart zone control systems Whole House Control Systems Work with 23 SEER Air Conditioners

New Furnace System Utilize Zoning Controls for Efficiency With Zone Controls, You Can Maintain the Same Temps in Every Zone of the Home Up to 30% More Efficient

Electronic Controls Provide Proportional and Accurate Temperature Control

Most Furnaces Work On Two Position Control (not very accurate) Two Position control action chart (heating action shown)

Electronically Controlled Furnaces Use Proportional Control Action Proportional Control Action

PID Control is Very Accurate Control More Common in Comm. Buildings Proportional Plus Integral & Derivative (PID) Proportional Plus Integral Plus Derivative (PID) control action

What We Know about ECM Motors They are Replacing Traditional PSC Motors on Many HVAC Applications

ECM Motors are 3 Phase Motors and Electronics in ONE Housing

ECM Motor Principles The motor is essentially a three phase motor with a permanent magnet rotor. The permanent magnet rotor contributes to the electrical efficiency of the ECM and also to its sensor-less ability to control the rpm (revolutions per minute) and commutation (when to alternate the cycle). The benefit of all of this technology is increased electrical efficiency and the ability to program more precise operation of the motor, over a wide range of HVAC system performance needs, to enhance consumer comfort.

CFM and ESP-AHU Fan Operation These variable speed air handlers are designed to deliver constant airflow (CFM) regardless of the external static pressure (ESP) in the ductwork. If too many supply registers are closed, a filter becomes clogged, or there is a restriction in the ductwork, the motor will automatically operate at a higher speed to compensate for the higher ESP. This may result in a higher operating sound level. These units have variable speed motors that automatically adjust to provide constant CFM from 0.0 to 0.6 w.c. static pressure. From 0.6 to 1.0 static pressure, CFM is reduced by 2% per 0.1 increase in static. Operation on duct systems with greater than 1.0 w.c. external static pressure is not recommended.

The ECM Motor Control The motor control is the brains of the device, where single phase (1Ø) 120 or 240 VAC 60 cycle (Hertz/frequency) power is connected. The control then converts AC power to DC power to operate the internal electronics, thus the name DC motor. The microprocessor in the motor control is programmed to then convert DC power (by means of electronic controls) to a three phase (3Ø) signal to drive the motor, thus the name Three Phase Motor. It also has the added ability to control the frequency (which controls the speed in revolutions per minute) and the amount of torque (current/power) it delivers to the motor.

The GE ECM Motor The GE ECM motor, currently used by most residential HVAC systems is a brushless DC, three-phase motor with a permanent magnet rotor. Motor phases are sequentially energized by the electronic control, powered from a single phase supply. These motors are actually made of two components, a motor control (control module) and a motor, sometimes called a motor module.

How does External Static Pressure relate to the reliability and efficiency of Premium ECM indoor blower motors? They are speed limited by manufacturer design so they will not overwork themselves if static pressure gets to high. If the motor gets to the speed limit from high static pressure (typically above the maximum pressure recommended by the OEM), in simple terms, it just runs at that level without continuing to add torque. If static pressure increases above this point (the speed limit) the motor will gracefully reduce airflow to protect itself, while still operating the system. If static pressure gets too high (typically well above the maximum pressure recommended by the OEM), the motor may oscillate (speed up, slow down, speed up, slow...).

ECM motors can save a significant amount of energy at lower static pressure by operating at lower speeds The closer the ESP is to the manufacturer rating the closer the unit is to running at the efficiency it was designed at. Higher static pressure equals to higher operating speeds and more energy usage by the motor to maintain airflow. Higher pressures mean higher operating speeds, more noise and consequently more input power, conversely, lower pressures result in very low power consumption and less noise. At higher static pressures the motor is using more energy to maintain airflow.

Where is ECM Motors Going to Be in 5 Years? More interfacing with electronic controls More reliable Smoother, thus quiter Used on all motors in the furnace, heat pumps, and air conditioners Networked and controlled via the WEB

Heat Pump, Furnaces, and ECM Motor Quiz 1. T F Heat Pump COP s go up when OSA temps go down. 2. T F UL Labs rate all HVAC equipment in the USA. 3. T F Heat Pumps can t work efficiently below 20 deg.f, and should be switched to fossil fuel or aux. heat. 4. T F Compressors in cold climate heat pumps tend to overheat due to the high compression ratio s. 5. T F ECM Motors in a furnace are really just a 3 phase motor. 6. T F ECM Motors will vary speed and cfm. 7. T F Modern furnaces can have up to 95% AFUE. 8. T F Electronic zone control can save up to 30% energy. 9. T F Modern thermostats are using Proportional not Digital Control 10. T F Heat pumps are more efficient when they control inside based on outside temperatures.

New Technologies in HVAC: What We Know and Where the Industry Is Heading Session 1 Any Questions?