Troubleshooting
24
CAUSE
SOLUTION
SYMPTOM
Poor Airflows
Supply air feels cold
Dehumidistat is not Operating
Humidity Levels are too High Condensation
is appearing on the windows
Humidity Levels are too Low
ERV and / or Ducts Frosting up
Condensation or Ice Build Up in Insulated
Duct to the Outside
• 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 ERV
• improper speed control setting
• 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
• 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
• ERV is set at too low a speed
• dehumidistat control set too low
• blower speed of ERV is too high
• lifestyle of occupants
• ERV airflows may be improperly balanced
• ERV airflows are improperly balanced
• malfunction of the ERV frost prevention system
• incomplete vapor barrier around insulated duct
• a hole or tear in outer duct covering
• 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 ERV
• have contractor balance 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 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
• 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 setting
• set dehumidistat lower
•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 vapor 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 ERV use
• increase speed of the ERV
• set dehumidistat higher
• decrease ERV blower speed
• humidity may have to be added through the use of humidifiers
• have a contractor balance ERV airflows
• Note: minimal frost build-up is expected on cores before
unit initiates defrost cycle functions
• have HVAC contractor balance the 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 vapor barrier is completely sealed
Excessive vibration
Dirt on fan wheels
Have a contractor service ERV
