Emerson VH User Manual

Excessive arcing in the 

canister

Drain valve clogged or defective

Verify that drain valve operates freely when activated. 

Clean valve and replace coil or valve if defective. 

Flush canister several times and replace if arcing 

persists

Improper water supply

If water is commercially softened, reconnect humidifier 

to raw water supply, drain canister, and restart If 

connected to hot supply, reconnect to cold water.

Insufficient drain rate

Increase drain rate by adjusting % pot on circuit board 

above the preset 87% (85%) to roughly 92% (90%).

Excessive iron content in water

Analyze iron cement of water. If it exceeds 0.1 mg/l, 

install a filter to remove iron from water supply.

On cold start-up, 

canister fills, high water 

alarm activates and 

humidifier fails to reach 

full amperage after 24 

hours

Conductivity of water too low

Turn the % pot to roughly 82% (80%). Restart 

humidifier. If canister fails to reach FLA in 24 hours, 

have water supply conductivity checked.

Fill solenoid not closing tightly

If humidifier returns to canister full condition, verity that 

the fill solenoid closes tightly.

No humidification

Humidifier pan not filling

Check water supply.
Check fill valve operation
Check drain stand pipe adjustment
Check for clogged waterline

Control not calling for humidity

Check monitor status

Humidity contact not pulling in

Check visually. If contact is made, check line voltage 

after contactor and fuses or CBs.
Check for open humidifier safety stat. Jumper between 

terminals P35-6 and P35-15. If contactor pulls in, 

replace safety. Remove jumper.

Humidifier bulb burned out

Replace bulb. Loosen lead on old bulb. Trim excess 

lead length on new bulb to avoid shorts.

Reheat will not operate; 

contactor not pulling in

Control not calling for heat

Check monitor status.

Reheat safety stat open

Jumper between terminals P34-1 and P34-2. If reheat 

operates, safety is open. Remove jumper. Replace 

safety.

Reheat not operating, 

contactor pulling in

Heater burned out

Turn off power and check heater continuity with Ohm 

meter.