Nortek VENMARCES VHC-42 User Manual (English)

Questions and Answers:

D
donald93Aug 21, 2025
What to do if Nortek VENMARCES VHC-42 compressor will not turn on?
- L
  lopezlindseyAug 21, 2025
  If the Nortek Heating System compressor will not turn on, there are several possible causes: * There may be no power. Ensure the main disconnect is on and measure the main terminal block for voltage. * The wiring might be incorrect. Verify if the compressor is wired correctly. * The controlled temperature may be lower (cooling) or higher (heating) than the thermostat setting. Adjust the thermostat setting. * The compressor may have failed, requiring replacement.
K
Kimberly LopezAug 25, 2025
Why Nortek VENMARCES VHC-42 motor and blower not functioning?
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  mark86Aug 25, 2025
  If the Nortek Heating System's motor and blower are not functioning, check the following: * Ensure that the electrical supply hasn't been interrupted by checking the unit circuit breaker. * Inspect the fan motor capacitor by checking the motor's electrical connections. * Examine the fan motor for failure and check the capacitor connections. * Verify the fan motor contactor for failure, checking both the contactor wiring and operation. * Check the fan drive belt for a tripped overload relay. * Confirm that the fan drive pulleys are securely fastened on the motor or fan shaft(s), setting the set screw setting at 100 in-lbs to 130 in-lbs.
X
xduarteAug 26, 2025
Why Nortek VENMARCES VHC-42 Heating System enthalpy wheel not running?
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  Michele DouglasAug 27, 2025
  If the Nortek Heating System's enthalpy wheel isn't running, here are some possible causes: * The unit might be in free cooling. Check the jumper wire for proper operation. * The unit may be in recirc defrost. Check the unit circuit breaker. * There could be a drive motor capacitor failure. Check the motor's electrical connections. * The drive motor might have failed. Check the capacitor connections and test the motor's operation with a new capacitor. * There might be an issue with the drive motor relay in the control box. Check the relay wiring. * The drive belt may be derailed or failed. Check for drive belt derailment off the drive pulley or failure. * The drive pulley might not be securely fastened. Check for a securely fastened pulley on the motor shaft.
E
efranklinAug 27, 2025
What causes high pressure switch to open in heating operation in Nortek Heating System?
- K
  Kimberly BarrettAug 28, 2025
  If the high pressure switch is open during heating operation in your Nortek Heating System, consider these potential issues: * The supply fan may have failed. Check if the wiring is correct and replace any failed components. * The outside air damper may not be open. Check the outside air damper operation and replace the actuator if it has failed. * The Dx coil might be too dirty. Clean the Dx coil. * The supply airflow may be too small. Check if components (coil, wheel, filter) are too dirty, if the motor is running at low speed or not running at all, and check for excessive pressure loss in the supply duct. * There could be a refrigerant overcharge. Charge the correct amount of refrigerant.
M
Melissa AllenAug 29, 2025
Why Nortek VENMARCES VHC-42 compressor runs but stops quickly?
- A
  Aaron LewisAug 29, 2025
  If your Nortek Heating System's compressor runs briefly and then stops, it could be due to: * Overload or fuse burnout. Check if the voltage is too low, the wiring is incorrect, or the wire gauge is sized correctly. Replace any blown fuses. * Activation of a low or high pressure switch. Refer to the solutions for when the high pressure switch is open and the low pressure switch is open.
J
Jennifer PageAug 31, 2025
What causes low pressure switch to open in cooling operation in Nortek VENMARCES VHC-42 Heating System?
- K
  Kyle PerezAug 31, 2025
  If the low pressure switch is open in the cooling operation of your Nortek Heating System, it could be due to: * A TXV failed in the closed position. Replace the TXV. * Supply blower failure. Replace the TXV or filter drier. * Insufficient supply airflow. Check if components (coil, wheel, filter) are too dirty, if the motor is running at low speed or not, and check for excessive pressure loss in the supply duct. * Loss of refrigerant charge. Check for and repair any leaks in the piping and refill refrigerant.
R
Rachael MosesSep 1, 2025
What causes low pressure switch to open in heating operation in Nortek Heating System?
- G
  Gail DeleonSep 1, 2025
  If the low pressure switch is open during heating operation in your Nortek Heating System, consider the following potential causes: * A TXV may have failed in the closed position. Replace the TXV. * The TXV or filter drier may be blocked. Replace the TXV or filter drier. * There could be a lack of water flow (WSHP). Check if the motorized water valve is opening completely and confirm the loop water pumps are running. * There might be insufficient water flow (WSHP). Check if the pump is sized correctly or if the water strainer is blocked. * The water entering temperature may be too low (WSHP). Consult the factory for operation outside the application range. * There may be a loss of refrigerant charge. Check and repair any leaks in the piping and refill refrigerant.
S
Susan BallSep 3, 2025
How to stop Nortek VENMARCES VHC-42 from making an annoying noise?
- L
  Luis BellSep 3, 2025
  If the Nortek Heating System is making an annoying noise, here are some things to check: * The blower wheel might be out of alignment. Remove the motor/blower assembly, and adjust the blower wheel. * Check for proper seal operation of the enthalpy wheel wiper seal.
D
dbellSep 4, 2025
What to do if air from Nortek VENMARCES VHC-42 supply diffusers too cold?
- A
  Amy AllenSep 4, 2025
  If the air from the supply diffusers of your Nortek Heating System is too cold, consider the following: * There may be an imbalance of supply and exhaust air. Check the filters and heat exchanger for blockage. * Check the balance of airflows. * Consider installing a post-heat module.
M
michaelblankenshipSep 6, 2025
Why Nortek Heating System compressor makes an abnormal sound?
- C
  Carol DavisSep 6, 2025
  If the Nortek Heating System's compressor is making an abnormal sound, it could be due to: * Reverse scroll operation. Reverse any two phases on the three-phase compressor. * A compressor quality issue. Replace the compressor.

Nortek VENMARCES VHC-42 Specifications

General

Brand	Nortek
Model	VENMARCES VHC-42
Category	Heating System
Language	English

Summary

Safety and Information

Safety Considerations

Explains the meaning of Warning, Caution, and Important notes.

Installation Basics

Electrical Connections and Power

Electrical Connections Overview

General safety and wiring considerations for electrical hookups.

Power Supply and Field Connection

Details on connecting main power supply and field wiring interfaces.

Piping Connections

Coil or WSHP Piping Connections

Guidelines for connecting heating/cooling coils and Water Source Heat Pump piping.

Start-up Procedures

Pre Start-up Procedure Checklist

A comprehensive checklist to complete before requesting unit start-up.

Unit Start-up and Verification

Start-up Procedure Steps

Detailed steps for initiating unit operation and verifying system performance.

Airflow Balancing and Flow Setting

Airflow Balancing Procedures

Guidance on balancing airflow for optimal unit performance.

Setting Airflow Rates

Maintenance Procedures

General Maintenance Overview

Recommendations for routine maintenance and inspection frequency.

Air Filter Replacement

Enthalpy Wheel Servicing

Enthalpy Wheel Cleaning and Inspection

How to clean the enthalpy wheel and inspect its seals and belt.

Cassette Removal Procedure

Coil and Refrigerant System Maintenance

Coil Cleaning Procedures

Methods for cleaning heat transfer coils to maintain efficiency.

Refrigerant System Components

Evaporator and System Checks

Evaporator Section and Direct Expansion Components

System Operation Verification

How to check and verify proper operation of all control modes.

Appendix F: Electrical Data

Full Load Amperage (FLA) and Heater Calculations

Tables and formulas for blower motor FLA and electric heater calculations.

Electric Heater Limitations

Appendix G: Standard Field Wiring Terminals

Electro-mechanical Controls Wiring

Terminal assignments and diagrams for electro-mechanical control systems.

DDC Controls Wiring Inputs and Outputs

Terminal assignments for Direct Digital Control systems, including inputs and outputs.

Appendix H: Terminal Control Diagrams

Occupied Ventilation and Timer Sensor Controls

Diagrams for occupied ventilation control via contacts or timer sensors.

Unoccupied Recirculation Control

VFD High Speed Fan Control

CO2 Ventilation and Smoke Detector Controls

Start-up Readings and Verification

Start-up Readings Table

Table for recording operational data during unit start-up.

Appendix K: Gas-fired Furnace Installation and Maintenance

Furnace Safety, Installation Requirements, and Venting

Covers safety warnings, installation rules, and venting requirements for gas furnaces.

Combustion Air, Gas Supply, and Piping

Details on air intake, gas supply, piping, and connections for gas furnaces.

Furnace Operation, Start-up, and Checks

Procedures for operating, starting up, and checking the gas furnace module.

Furnace Start-up and Operation

Furnace Operating and Safety Instructions

Essential safety precautions and operating guidelines for the furnace module.

Furnace Start-up Procedures

Step-by-step instructions for starting up the gas furnace module.

Burner Flame and System Checks

Burner Flame Characteristics

How to interpret burner flame appearance for proper adjustment.

Fenwal Ignition Control Systems

Fault Conditions, Service Checks, and Security Devices

Information on ignition control fault codes, service checks, and safety devices.

Furnace Module Maintenance and Operation

Guidelines for annual inspection and operational checks of the furnace module.

Sequence of Operation Modes

Explains the different operating sequences for the ignition control.

Appendix L: Electric Heating Coil Information

Mechanical and Electrical Installation

Procedures for physically and electrically installing electric heating coils.

Operating and Maintenance Procedures

Guidelines for operating, maintaining, and inspecting electric coil heaters.

Appendix N: Troubleshooting Guide

Unit and Compressor Troubleshooting

Solutions for common unit issues like power, noise, and compressor problems.

Compressor and Refrigerant System Troubleshooting

Guidance for diagnosing and resolving compressor and refrigerant system issues.

Appendix O: Maintenance Summary Chart

VHC-36, -42, -50 Maintenance Schedule

Appendix R: Refrigerant Charge Adjustment

Refrigerant Handling Precautions and Measurement

Safety, regulatory, and measurement procedures for refrigerant handling.

Sub-cooling and Superheat Adjustment

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