Troubleshooting - Nu-Air NU0103 Operating, Maintaining & Installing

12 Troubleshooting

SYMPTOM
Frosting up of HRV and/or
Duct(s).
Supply air feels cool.
Outside duct has ice build-up or
condensation.
Water in the bottom of HRV.
Poor air flow(s).
Humidity levels too low.
Humidity levels too high.
Dehumidistat is not working.
Rev 2.3 July 17, 2017
EXPLANATION
HRV air flows incorrectly balanced.
HRV defrost system is not working.
HRV air flows incorrectly balanced.
Improper location of supply grills.
Velocity of air is too high.
Extremely cold outside temperatures.
Heating coil is not working.
Improperly installed vapour barrier
around insulated duct.
Drain pans are plugged.
Incorrect connections of HRV drain
lines.
HRV is not level.
Drain lines plugged.
HRV heat exchange core improperly
installed.
HRV incorrectly balanced.
Filters need to be cleaned.
Hoods needs to be cleaned.
Grills are closed.
Inline dampers are closed.
Low power supply.
Wrong size ducting.
Under-sized HRV.
HRV is not working.
HRV air flows incorrectly balanced.
Dehumidistat control set too low.
HRV air flows
incorrectly balanced.
HRV undersized.
High humidity areas not ventilated
properly.
Dehumidistat is not working.
Incorrect connection of outside low
voltage wiring between HRV and
Dehumidistat.
ANSWER
Balance HRV.
Install dampers.
Check defrost system.
Note minimal frost build up is expected
on cores before unit initiates defrost
cycle function.
Balance HRV.
Locate grills high on walls or in ceiling.
Adjust diffusers, resize duct.
Add a duct heater.
Call your service contractor.
Tape all joints.
Ensure the vapour barrier is completely
sealed and insulated.
Look for kinks in the line.
Check water drain connections.
Ensure that water drains from pan.
Tape all joints.
Use proper airflow measuring
equipment.
Open grills.
Remove obstructions in duct(s),
hoods(s), and grill(s).
Balance airflow.
Clean filter.
Have a professional look at the system.
Balance Air Flow(s).
Increase Dehumidistat.
Humidifiers may need to be added.
Balance airflow.
Set dehumidistat.
Check outside wiring for short.
Check wall switch for correct
connection.
Check wires are connected to proper
terminals at the HRV.
23