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6. Operating Problems and Solutions

Operating Problems and Solutions

As with any appliance, problems can arise with your HRV, even if it is operated according to the manufacturer's instructions. Some problems will be very simple to diagnose and remedy, while others may require the services of a qualified contractor. The following HRV Troubleshooting Guide indicates when a contractor should be called. For more specific information, consult your owner's manual.


HRV Troubleshooting Guide

Problem Possible causes and solutions
HRV not operating
  • Verify that HRV control is turned on.
  • Ensure that HRV is plugged in and electrical cord is not damaged.
  • Check for tripped circuit breaker or blown fuse. If either has occurred, call a contractor. (Do not reset the breaker or replace a fuse before determining what caused the electrical problem, as this is a fire or shock hazard.)
  • If problem persists, call a contractor
HRV operating but little or no airflow at grilles
  • Check exterior hoods for blockage and
    clean as required.
  • Check ducts to exterior hoods and clean as required.
  • Check filters and clean or replace as required.
  • Check ducts/registers in rooms for blockage (closed damper, toys, etc.).
  • Check core for freezing/frosting (see Core freezes below).
  • Check ducts for leakage or disconnection. Seal any loose joints with duct tape.
  • If problem persists, call a contractor.
  • Ensure the HRV door is securely closed and tight, and all internal gaskets are properly seated.
Core freezes
  • Open door and let ice melt (some cores can be easily removed and thawed in a sink).
  • Check filters and clean or replace as required.
  • With some HRV models,the defrost mechanism or preheater can be checked by following the manufacturer 's instructions in the owner's manual.
  • If problem persists, call a contractor.Your system may need rebalancing to increase exhaust flow or decrease supply flow.
HRV runs on one speed only
  • Check all switches for malfunctions by varying the settings.
  • If unit remains on same speed, call a contractor.
Damaged duct insulation jacket
  • If the insulation is wet,has any ice build-up or if there is water on the floor,replace and properly seal the damaged insulation.
  • If the insulation is not damaged, use duct tape to repair any punctures in the jacket.
Cold drafts in living quarters
  • Check for blockage of exhaust air stream.
  • Check core for freezing.
  • If problem persists, ask installer to provide diffusers, relocate fresh air outlets, add additional
    outlets, or add a preheater, as appropriate.
Poor air quality/ excess moisture throughout the house
  • Adjust dehumidistat.
  • Check core for freezing.
  • Reduce sources of humidity.
  • Run HRV at a higher speed.
  • Ensure HRV is operating properly (check airflow using plastic trash bag technique).
  • If problem persists,the HRV 's minimum continuous ventilation rate may be inadequate.
  • Call a contractor.
Air too dry in winter
  • Adjust dehumidistat.
  • Run HRV on lowest setting.
  • Run HRV intermittently.
  • Consider installing a control to run HRV intermittently.
  • Sensation of dryness may be caused by chemicals.Control pollutant at the source.
  • Consider installing a humidifier (if you do so, make sure you clean it regularly).
  • Consider installing an energy recovery ventilator (ERV), which can help with humidity problems (see “Energy Recovery Ventilators”).This is a more expensive solution than any of the above. Some HRVs can be converted to ERVs, at less cost than installing a new unit.
Unusual noise and vibrations
  • Oil the fan motors (if not self-lubricating) using non-detergent motor lubricating oil.
  • Inspect and clean fan blades and heat-exchange core as required.
  • If problem persists, call a contractor.

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Source: Natural Resources Canada (NRCan) - Office of Energy Efficiency

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