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Troubleshooting
Symptom
Cause
Solution
Poor airflow(s)
Mesh on outside hoods plugged
Filters plugged
Core obstructed
House grilles closed or blocked
Dampers closed (if installed)
Poor power supply at site
Ductwork is restricting HRV/ERV
Improper speed control setting
HRV/ERV airflow improperly balanced
Clean exterior hoods or vents
Remove and clean filter
Remove and clean core
Check and open grilles
Open and adjust dampers
Have electrician check supply voltage at house
Check duct installation
Increase the speed of the HRV/ERV
Have contractor balance the HRV/ERV
Supply air feels
cold
Poor location of supply grilles; airflow may irritate occupants
Outdoor temperature extremely cold
Locate the grilles high on the walls or under the baseboards;
install ceiling mounted diffuser or grilles so as not to direct air-
flow onto occupants (e.g. over a sofa).
Turn down the HRV/ERV supply speed. A small duct heater
(1kw) could be used to temper the supply air.
Placement of furniture or closed doors restricting movement of
air in home; consider rearranging.
If supply air is ducted into furnace return, the furnace fan may
need to run continuously to distribute ventilation air comfortably.
Dehumidistat is
not operating
Outdoor temperature is above 59ºF (15ºC)
Improper low−voltage connection
External low voltage is shorted out by a staple or nail
Check dehumidistat setting; it may be OFF
Dehumidistat is functioning normally (see Auto Dehumidistat
Disable in this manual).
Check that the correct terminals have been used,
Check external wiring for a short.
Set the dehumidistat at the desired level.
Humidity levels
are too high;
condensation is
appearing on
windows
Dehumidistat set too high
HRV/ERV unit is undersized to handle a hot tub, indoor pool,
etc. (occupant lifestyle)
Moisture coming into the home from an unvented or unheated
crawl space
Moisture remaining in washroom and/or kitchen areas
Condensation seems to form in the spring and fall seasons
HRV/ERV is set at too low a speed
Set dehumidistat at lower level.
Cover pool, hot tub, when not in use.
Avoid hanging clothes to dry indoors, storing wood indoors, and
venting dryer inside.
Vent crawl space and place a vapor barrier on the floor of the
crawl space.
Ducts from washroom should be sized to remove moist air as
effectively as possible; use of a bathroom fan for short periods
will remove additional moisture.
On humid days, as seasons change, some condensation may
appear but the home’s air quality will remain high with some
HRV/ERV use.
Increase speed of HRV/ERV.
Humidity levels
are too low
Dehumidistat control set too low
Blower speed of HRV/ERV is too high
Occupant lifestyle issue
HRV/ERV airflows may be improperly balanced
Set dehumidistat at higher level.
Decrease HRV/ERV blower speed.
Humidity may have to be added through use of humidifiers.
Have a contractor balance HRV/ERV airflows.
HRV units and/or
ducts frosting up
HRV air flows are improperly balanced
Malfunction of the HRV defrost system
Note – minimal frost build−up is expected on cores before unit
initiates defrost cycle functions.
Have HVAC contractor balance the HRV airflows.
Ensure damper defrost is operating during self−test.
Condensation or
ice build−up in in-
sulated duct to
the outside
Incomplete vapor barrier around insulated duct
Hole or tear in outer duct covering
Tape and seal all joints.
Tape any holes or tears made in the outer duct covering.
Ensure that the vapor barrier is complete sealed.
Water in the bot-
tom of the
HRV/ERV unit
Drain pans plugged
Improper connection of HRV/ERV drain lines
HRV/ERV is not level
Drain lines obstructed
HRV/ERV heat exchange core is not properly installed
Ensure o−ring on drain nozzle sits properly.
Look for kinks in the drain line.
Check water drain connections.
Make sure water drains properly from pan(s).
