13
VAPORMIST
®
TROUBLESHOOTING GUIDE
NOTE:
Probe rod corrosion or probe head material aging may cause level control system failure. This generally does not occur in the
first two years of operation.
.
PROBLEM
POSSIBLE CAUSE
RECOMMENDED ACTION
Humidifier does not heat.
Incorrect or nonexistent supply
voltage to unit
Check main line safety switch.
Check main line fuses.
Check for proper supply voltage.
Incorrect or nonexistent control
voltage
Reset control transformer circuit breaker.
Check for 24 VAC control circuit voltage at T-1 and T-2 on the
control board.
Humidistat not calling
Set humidistat to call. Inspect for faulty humidistat.
Safety controls open
Check safety controls, air flow switch, and high humidistat.
Humidifier will not fill.
No water pressure at valve
Check water supply/shut-off valves.
Faulty water fill valve
Check for 24 volts at the fill valve.
Plugged strainer
Check strainer.
Plugged valve
Check valve.
Faulty control board
Verify control voltage across the fill valve output.
Humidifier does not stop
filling.
Lack of tank to probe electrical
continuity
Water conductivity must be 100 micromhos/cm (2 gr/gal) or
34.2 mg/liter.
Add salt to the tank. If this solves the problem, consult factory for
further advice.
Fill valve stuck open
Check valve for foreign matter.
Drain valve not closed
Fill valve installed backward
Check for correct water flow through valve by noting arrow.
Autodrain mode
Humidifier may be in periodic drain and flush. Check controller
display.
Low output
Electric drain valve not seating
Correct the cause of leakage or replace valve.
Fill valve stuck open
Check valve for foreign matter.
Unit short-cycles.
Controller cycle rate set too low
Review controller cycle set point.
Reduced or no output
even though water is at
the proper level
Heater malfunctioning
Verify that proper voltage is being applied to heaters. Check heater
amp draw and compare to wiring diagram ratings.
Malfunctioning control system
Replace heater contactor if not functioning. Verify auxiliary limit
controls (humidistat, air flow proving switch, etc.) and reset,
replace or calibrate as needed.
VMOM-0600.PDF 13
11/19/2009 9:59:11 AM
