TROUBLESHOOTING
Problem
Air is too dry
Air is too humid
Persistent condensation
on window
Poor Air Flows
Supply air feels cold
ERV and / or Ducts
Frosting up
Condensation or Ice
Build Up in Insulated
Duct to the Outside
18
Causes
Dehumidistat control is set too low
ERV out of balance
Dehumidistat control is set too high
Sudden change in temperature
Storing too much wood for heating
Dryer vent exhaust is inside home
Poor air circulating near windows
ERV out of balance
Well sealed basement door is closed
Improper adjustment of dehumidistat
control
ERV out of balance
-1/4" (6mm) 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 air-
flow may irritate the occupant
-Outdoor temperature extremely cold
-ERV air flows are improperly
balanced
-Malfunction of the ERV defrost
system
-Incomplete vapor barrier around
insulated duct
-A hole or tear in outer duct covering
Solutions
Increase the desired level of humidity. Change ventilation mode from
continuous mode to standby.
Balance ERV
Reduce the desired level of humidity. Combine this step with use of con-
tinuous exchange mode.
Wait until outside temperature stabilizes (winter). Heating will also
improve situation.
Store a majority of your wood outside. Even dried, a cord of wood con-
tains more than 20 gallons of water.
Arrange outside vent for dryer.
Open curtains or blinds. Bay or bow windows may require mechanical
method.
Balance ERV
Open the door or install a grille on the door.
Reduce the desired level of humidity. Combine this with the use of con-
tinuous exchange mode.
Balance ERV
-Clean exterior hoods or vents
-Remove and clean filter
-Remove and clean core
-Check and open grilles
-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
-Note: minimal frost build-up is expected on cores before unit initiates
defrost cycle functions
-Have HVAC contractor balance the ERV
-Tape and seal all joints
-Tape any holes or tears made in the outer duct covering
-Ensure that the vapor barrier is completely sealed.