Service Manual

Is there continuity
through the normally
c
losed intake pressure
switch?
(see photo at right)
Y
Replace
intake pressure switch.
(see “Intake Pressure Switch
Replacement Procedure”)
Switch OK.
D
oes Blower Energize?
Does purge LED
illuminate on the ignition
module?
Remove hose from intake
pressure switch and
Restart heater.
Does purge LED illuminate?
N
Y
With manometer, take a
reading from the inlet tube
pressure tap. Is reading
negative (-)1.2" W.C.
or more?
(see illustration below)
N
S
ee “Vent Safety Switch Testing
a
nd Replacement”
or
Exhaust Pressure Switch Tesinting
and Replacement”
or
“Blower Testing and Replacement”
Y
N
Y
N
N
Y
Is intake vent system
obstructed?
Y
N
Call for technical support.
Clear obstruction.
See “Exhaust Pressure Switch Testing
and Replacement”)
or
“Blower Testing and Replacement”
Service Procedure EF-XII
Intake Pressure Switch Testing and Replacement
Used on EF water heaters prior to “CF” serial number.
Is there continuity
through the normally
closed intake pressure
switch?
(see photo above)
Y
Isolate (disconnect) heater from
intake vent system and
Restart heater.
Does purge LED illuminate?
N
Y
N
Disconnect red wire leads from
pressure switch and check
continuity through switch.
WARNING
1
20 volt potential exposure. Use caution
m
aking voltage checks to avoid personal injury.
Notice:
The intake pressure switch is not used
on serial number “CF” and later.
Inlet Tube
pressure tap
69
69