11
CRU
®
V-DI TROUBLE-SHOOTING GUIDE
(LW415 Electronic Water Level System Only)*
PROBLEM
Humidifier will
not heat
Humidifier will
not fill
Water float
valve does not
close
Reduced or no
output even
though water is
at the proper
level
RECOMMENDED ACTION
Verify control voltage across secondary leads of
transformer. Reset transformer circuit breaker.
Set humidistat to call. Inspect for faulty humidistat.
Check safety control. (Air flow switch, high limit
humidistat, etc.)
Verify control voltage from float switch and transformer
secondary common.
Check manual water supply. Valve, minimum 30 psi
water pressure.
Check to make sure that valve float & stem moves freely.
Check float valve seat.
Obstruction in drain valve will not allow complete
closure, clean or replace valve.
Close drain valve.
Float ball has water leak. Float valve seat defective,
replace.
Readjust float valve rod, so water level reaches 1/4-3/8"
from overflow edge when water is at ambient or cold
state. Excessive water pressure, 100 psi maximum.
Obstruction will not allow float valve to seat properly,
clean or replace with new seat.
Verify that proper voltage is being applied to heaters.
Check heaters (amp draw and compare to wire diagram
ratings).
Heater contactor not functioning, replace. Service fuses
blown. Auxiliary limit controls not allowing system to
operate (duct humidistat, air flow proving switch, etc.).
Reset, replace, or calibrate as required. Faulty or
inaccurate humidistat, replace or calibrate.
On delay relay delay time is 10-15 seconds. Check
relays.
Check for proper operation.
READY
WATER
Off
Off
On
On
POSSIBLE CAUSE
Control transformer
Humidistat is not calling
Safety controls open
Low water float switch
No water pressure at valve
Malfunctioning water float
valve
Plugged float valve
Open drain valve
Manual drain valve not closed
Malfunctioning float valve
Water passing into overflow
stand pipe
Float valve stuck
Heater malfunctioning
Malfunctioning control system
Time delay/interlock relays
Low water cut-off switch
*For VAPOR-LOGIC
2
trouble-shooting, see the VAPOR-LOGIC
2
Operations and Maintenance Manual.