12
CRU
®
V TROUBLE-SHOOTING GUIDE (VAPOR-LOGIC
®
3
only)
*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 non-existent supply
voltage to unit
Check main line safety switch .
Check main line fuses.
Check for proper supply voltage.
Incorrect or non-existent 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 limit 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 probes’ electrical
continuity; water conductivity 100
micromhos/cm (2 gr/gal) or 34.2
mg/1 min.
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, note arrow.
Auto-drain mode
Humidifier may be in periodic drain and flush. Check controller
display.
Low output
Electric drain valve not seating
Correct cause of leakage or replace valve.
Fill valve stuck open
Check valve for foreign matter.
Unit short cycles
Controller cycle rate set to 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
Heater contactor not functioning, replace. Service fuses blown.
Auxiliary limit controls not allowing system to operate (dust
humidistat, air flow proving switch, etc.) Reset, replace or calibrate
as required. Faulty or inaccurate humidistat, replace or calibrate.
