Troubleshooting

Installation, Operation & Maintenance	HEV/H SERIES	Heat Controller, Inc.

General

If operational difﬁculties are encountered, perform the preliminary checks below before referring to the troubleshooting charts.

•Verify that the unit is receiving electrical supply power.

•Make sure the fuses in the fused disconnect switches are intact.

After completing the preliminary checks described above, inspect for other obvious problems such as leaking connections, broken or disconnected wires, etc. If everything appears to be in order, but the unit still fails to operate properly, refer to the “DXM2 Troubleshooting Process Flowchart” or “Functional Troubleshooting Chart.”

DXM2 Board

DXM2 board troubleshooting in general is best summarized as verifying inputs and outputs. After inputs and outputs have been veriﬁed, board operation is conﬁrmed and the problem must be elsewhere. Below are some general guidelines for troubleshooting the DXM2 control.

Field Inputs

Conventional thermostat inputs are 24VAC from the thermostat and can be veriﬁed using a voltmeter between C and Y1, Y2, W, O, G. 24VAC will be present at the terminal (for example, between “Y1” and “C”) if the thermostat is sending an input to the DXM2 board.

Proper communications with a thermostat can be veriﬁed using the Fault LED on the DXM2. If the control is NOT in the Test mode and is NOT currently locked out or in

a retry delay, the Fault LED on the DXM2 will ﬂash very slowly (1 second on, 5 seconds off), if the DXM2 is properly communicating with the thermostat.

Sensor Inputs

All sensor inputs are ‘paired wires’ connecting each component to the board. Therefore, continuity on pressure switches, for example can be checked at the board connector. The thermistor resistance should be measured with the connector removed so that only the impedance of the thermistor is measured. If desired, this reading can be compared to the thermistor resistance chart shown in the DXM2 AOM manual. An ice bath can be used to check the calibration of the thermistor.

Outputs

The compressor and reversing valve relays are 24VAC and can be veriﬁed using a voltmeter. For units with PSC blower motors, the fan relay provides a contact closure to directly power the blower motor, or provide 24VAC to an external fan relay. For units with ECM blower motors, the DXM2 controls the motor using serial communications, and troubleshooting should be done with a communicating thermostat or diagnostic tool. The alarm relay can either be 24VAC as shipped or dry contacts for use with DDC controls by clipping the JW1 jumper. Electric heat outputs are 24VDC “ground sinking” and require a voltmeter set for DC to verify operation. The terminal marked “24VDC” is the

24VDC supply to the electric heat board; terminal “EH1” is stage 1 electric heat; terminal “EH2” is stage 2 electric heat. When electric heat is energized (thermostat is sending a “W” input to the DXM2 controller), there will be 24VDC between terminal “24VDC” and “EH1” (stage 1 electric heat) and/or “EH2” (stage 2 electric heat). A reading of 0VDC between “24VDC” and “EH1” or “EH2” will indicate that the DXM2 board is NOT sending an output signal to the electric heat board.

Test Mode

Test mode can be entered for 20 minutes by pressing the Test pushbutton. The DXM2 board will automatically exit test mode after 20 minutes.

Advanced Diagnostics

If a communicating thermostat or diagnostic tool is connected to the DXM2, additional diagnostic information and troubleshooting capabilities are available. The current status of all DXM2 inputs can be veriﬁed, including the current temperature readings of all temperature inputs. With a communicating thermostat the current status of the inputs can be accessed from the Service Information menu. In the manual operating mode, most DXM2 outputs can be directly controlled for system troubleshooting. With a communicating thermostat the manual operating mode can be accessed from the Installer menu. For more detailed information on the advanced diagnostics of the DXM2, see the DXM2 Application, Operation and Maintenance (AOM) manual (part #97B0003N15).

DXM2 Troubleshooting Process Flowchart/Functional Troubleshooting Chart

The “DXM2 Functional Troubleshooting Process Flowchart” is a quick overview of how to start diagnosing a suspected problem, using the fault recognition features of the DXM2 board. The “Functional Troubleshooting Chart” on the following page is a more comprehensive method for identifying a number of malfunctions that may occur, and is not limited to just the DXM2 controls. Within the chart are ﬁve columns:

•The “Fault” column describes the symptoms.

•Columns 2 and 3 identify in which mode the fault is likely to occur, heating or cooling.

•The “Possible Cause column” identiﬁes the most likely sources of the problem.

•The “Solution” column describes what should be done to correct the problem.

WARNING!

WARNING! HAZARDOUS VOLTAGE! DISCONNECT ALL ELECTRIC POWER INCLUDING REMOTE DISCONNECTS BEFORE SERVICING.

Failure to disconnect power before servicing can cause severe personal injury or death.

HEV/H specifications

The Heat Controller HEV/H series represents a significant advancement in heating technology, designed to provide efficient and effective climate control for both residential and commercial spaces. This innovative range of heat pumps combines cutting-edge features with user-friendly functionality to offer a reliable solution for modern heating needs.

One of the standout features of the HEV/H series is its advanced inverter technology. This system allows the heat pump to adjust its output based on the specific heating requirements of the environment. By varying the compressor's speed, the HEV/H maintains a consistent temperature while significantly reducing energy consumption. This not only lowers utility bills but also reduces environmental impact, making it a more sustainable option compared to traditional heating methods.

The HEV/H series is equipped with a high-efficiency heat exchanger, which maximizes heat transfer and enhances overall performance. This component ensures that the system can operate effectively even in colder climates, providing reliable heating throughout the winter months. Additionally, the unit’s low noise operation is designed to maintain a peaceful environment, making it suitable for bedrooms, offices, and other noise-sensitive areas.

Another notable characteristic of the HEV/H series is its smart control features. Integrated with Wi-Fi connectivity, users can conveniently manage their heating settings remotely via a smartphone app. This feature allows for customized scheduling and temperature control, ensuring optimal comfort and convenience. Users can also receive real-time notifications on energy consumption and system performance, enhancing user engagement and control.

The HEV/H series also emphasizes durability and longevity. Constructed with high-quality materials, the units are designed to withstand the rigors of daily use while requiring minimal maintenance. The incorporation of advanced filtration systems helps to improve indoor air quality by capturing dust and allergens, which is especially beneficial for individuals with allergies or respiratory issues.

In summary, the Heat Controller HEV/H series exemplifies modern heating technology with its combination of efficiency, control, and user-friendly features. Its inverter technology, high-efficiency heat exchangers, smart connectivity, and durable construction make it an outstanding choice for anyone seeking to enhance their indoor climate while being conscious of energy usage and environmental impact. Whether for a home or business, the HEV/H series is poised to deliver exceptional heating solutions tailored to diverse needs.

Heat Controller HEV/H manual Troubleshooting

Models: HEV/H