97-610, 97-6152 • REV. 7/04
PRESSURE
W
ASHER
T
ro
u
b
leshooting Guide
22
Disconnect the pilot and ignition lines from the gas
valve. Disconnect union in main burner line. (Re-
move the nuts from the U-bolts, item 21 on page
24). Slide burner manifold out through shell open-
ing.
2. TO CLEAN BURNER JETS:
Select proper size drill for type of gas involved. Use
vise to hold drill and to ream out each jet orifice.
If the water heater will be exposed to freezing weather,
an antifreeze solution should be circulated through the
coils by whatever means are available for the particular
system the water heater is used on.
BURNER TROUBLESHOOTING
Millivolt System Check:
This machine has a thermopile self-powered combina-
tion gas control. Before checking the millivolt system,
the following operations should be performed and ob-
servations made:
1. Inspect system for proper wiring.
2. The switch leads and all wire connections should
be cleaned and tightened to eliminate all unneces-
sary resistance.
3. Clean and/or adjust pilot for maximum flame im-
pingement on the thermopile.
4. If pilot will not remain lit when gas cock dial is re-
leased, check automatic pilot (Step D).
MAINTENANCE & SERVICE
TERM
TERM
TERM
TH
TP
TH
TP
MILLIVOLT
OPERATOR
TERMINAL
PANEL
Check
Test
To Test
Connect
Meter
Leads To
Terminals
Switch
Flow &
Burner
Contacts
Meter
Reading
Should
Be
A
Complete
System
2 & 3
Closed
100 MV or
More
B
Thermopile
Output
1 & 2
Open
Greater
than 250
C
System
Resistance
1 & 3
Closed
Less than
35
D
Auto/Pilot
Dropout
1 & 2
Open
Between
120 - 30
MV
The millivolt system and individual components may be
checked with a DC millivolt meter having a 0-1000 MV
range. Conduct each check as shown in the chart be-
low by connecting the meter test leads to terminals as
indicated. All readings are closed circuit.
A. Complete Millivolt System Check
(“A” Reading = Switch contacts CLOSED - Gas
Cock Dial “ON” - Main burner should come ON).
1. If the reading is more than 100 millivolts and the
automatic valve still does not come on, replace
the automatic valve operator.
2. If the closed circuit reading (“A” Reading) is less
than 100 millivolts, determine cause for low read-
ing - proceed as follows:
B. Thermopile Output Reading Check
(“B” Reading = Switch contacts OPEN - Main burner
OFF).
If the minimum 250 millivolt reading is not ob-
tainable, readjust pilot for maximum millivolt out-
put. If millivolt reading is still below minimum
specified, replace thermopile.
2 Lead Thermopile
Equivalent
To (CP-2)
Igniter
Pilot 2CH-2
or
Equivalent
To Burner
Flow Switch
Gas
Valve
2 Lead
Thermopile
Connections