Specifications

14
VAPORMIST
®
DI TROUBLESHOOTING GUIDE
PROBLEM POSSIBLE CAUSE RECOMMENDED ACTION
Humidifier will not heat.
Control transformer Reset control transformer circuit breaker.
Humidistat is not calling Set humidistat to call. Inspect for faulty humidistat.
Safety controls open Check safety controls, air flow switch, high limit humidistat, etc.
Low water cutoff Check at board 32 and 33. Measure 0 volts for closed switch,
approximately 2.5 volt for A.C. open switch.
Humidifier will not fill.
No water pressure at valve Check manual water supply valve for minimum 25 psi (172 kPa)
water pressure.
Malfunctioning float switch Check to make sure that float moves freely on stem.
Plugged fill valve Check fill valve inlet.
Humidifier does not stop
filling.
Open drain valve Obstruction in drain valve will not allow complete closure. Clean or
replace valve.
Manual drain valve not closed Close drain valve.
Fill valve stuck open Check valve for foreign matter, water-logged float, broken float arm
worn valve stopper.
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 14 11/19/2009 9:59:11 AM