Troubleshooting
Table 16. 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 ERV
•
Improper speed control setting
•
ERV airflow improperly balanced
•
Clean exterior hoods or vents
•
Remove and clean both filter and core
•
If unit is equipped with MERV 13 filters,
replace every 3 months.
•
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 the 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 airflow onto occupants (e.g. over
a couch)
•
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
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 59
º
F (15
º
C)
•
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
“Dehumidistat Disable” on page 10)
•
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
•
ERV unit is undersized to handle a hot tub,
indoor pool, etc. (Occupant Lifestyle)
•
Moisture coming into the home from an non-
vented or non-heated crawl space
•
Moisture remaining in washroom and/or
kitchen areas
•
Condensation seems to form in the spring and
fall seasons
•
ERV is set at too low a speed
•
Set dehumidistat at lower level
•
Cover pool or 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 ERV use
•
Increase speed of ERV
Humidity levels are too low
•
Dehumidistat control set too low
•
Blower speed of ERV is too high
•
Occupant lifestyle issue
•
ERV airflows may be improperly balanced
•
Set dehumidistat at higher level.
•
Decrease ERV blower speed
•
Humidity may have to be added through use
of humidifiers
•
Have a contractor balance ERV airflows
ERV units and/or ducts frosting up
•
ERV air flows are improperly balanced
•
Malfunction of the ERV defrost system
•
NOTE: Minimal frost build-up is expected on
cores before unit initiates defrost cycle.
•
Have HVAC contractor balance the ERV
airflows
•
Ensure damper defrost is operating during
self−test
Condensation or ice build−up in insulated 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 bottom of the ERV unit
•
Drain pans plugged
•
Improper connection of ERV drain lines
•
ERV is not level
•
Drain lines obstructed
•
ERV heat exchange core is not properly
installed
•
Look for kinks in the drain line
•
Check water drain connections
•
Make sure water drains properly from pan(s)
Residential Energy Recovery Ventilators
32
®
