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SYMPTOM CAUSE SOLUTION
Poor Air Flows
Supply air feels cold
Dehumidistat is not Operating
Humidity Levels are too High
Condensation is appearing on the windows
Humidity Levels are too Low
HRV/ERV and / or Ducts Frosting up
Condensation or Ice Build Up in Insulated
Duct to the Outside
Water in the bottom of the HRV/ERV
• 1/4” (6 mm) mesh on the outside hoods is plugged
• filters plugged
• core obstructed
• house grilles closed or blocked
• dampers are closed if installed
• poor power supply at site
• ductwork is restricting HRV/ERV
• improper speed control setting
• HRV/ERV airflow improperly balanced
• poor location of supply grilles, the airflow may irritate
the occupant
• outdoor temperature extremely cold
• outdoor temperature is above 15°C (59°F)
• improper low voltage connection
• external low voltage is shortened out by a staple or nail
• check dehumidistat setting it may be on OFF
• dehumidistat is set too high
• HRV/ERV is undersized to handle a hot tub, indoor pool, etc.
• lifestyle of the occupants
• moisture coming into the home from an unvented or
unheated crawl space
• moisture is remaining in the washroom and kitchen areas
• condensation seems to form in the spring and fall
• HRV/ERV is set at too low a speed
• dehumidistat control set too low
• blower speed of HRV/ERV is too high
• lifestyle of occupants
• HRV/ERV air flows may be improperly balanced
• HRV/ERV air flows are improperly balanced
• malfunction of the HRV/ERV defrost system
• incomplete vapour barrier around insulated duct
• a hole or tear in outer duct covering
• drain pans plugged
• improper connection of HRV/ERVs drain lines
• HRV/ERV is not level
• drain lines are obstructed
• HRV/ERV heat exchange core is not properly installed
• 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 HRV/ERV
• locate the grilles high on the walls or under the baseboards,
install ceiling mounted diffuser or grilles so as not to directly
spill the supply air on the occupant (eg. 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 is restricting the
movement of air in the home
• if supply air is ducted into furnace return, the furnace fan
may need to run continuously to distribute ventilation
air comfortably
• dehumnidistat 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 setting
• set dehumidistat lower
• cover pools, hot tubs when they are not in use
• avoid hanging clothes to dry, storing wood and venting clothes
dryer inside. Heating wood may have to be moved outside
• vent crawl space and place a vapour barrier on the floor
of the crawl space
• ducts from the 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 the seasons change, some condensation
may appear but the homes air quality will remain high with
some HRV/ERV use
• increase speed of the HRV/ERV
• set dehumidistat higher
• decrease HRV/ERV blower speed
• humidity may have to be added through the use of humidifiers
• have a contractor balance HRV/ERV airflows
• Note: minimal frost build-up is expected on cores before
unit initiates defrost cycle functions
• have HVAC contractor balance the HRV/ERV
• ensure damper defrost is operating during self-test
• tape and seal all joints
• tape any holes or tears made in the outer duct covering
• ensure that the vapour barrier is completely sealed
• ensure O-Ring on drain nozzle sits properly
• look for kinks in line
• check water drain connections
• make sure water drains properly from pan
Troubleshooting your HRV/ERV System