Pentair MASTERTEMP MT125HD Installation And User Manual page 36

28 | Section 3. Troubleshooting
Heater Will Not Fire - C
Start
Is "SER VICE HEATER" LED
"on"?
YES
If any red diagnostic LED's
(AGS, AFS, SFS, HLS, PS, or
THERMIST OR) come "on", go
to to Pages 30 and 31.
CONTINUE
Did burner fire at all?
YE S
Go to "BURNER
TROUBLESHOOTING"
(Page 32)
Go to "HEATER WILL NOT
FIRE-D" (Page 31)
Replace Ignition Control
Module.
NO
Check for 24 VAC between
VA L and GND terminals on
Ignition Control Module.
SEE NOTE 2.
YES
Check for 24 VAC between
VA L and GND terminals on
Control Board. SEE NOTE 2.
NO
Fix wiring between VA L and
GND terminals of Ignition
Control Module and Control
Board.
MasterTemp 125 Pool and Spa Heater Installation and User's Guide
NO
Turn off power to
heater for 5 seconds,
and turn back on.
Make sure tempera-
ture setting is above
water temperature.
NO
Wa it one minute.
Does heater fire and
stay on?
NO
Did Blower come on?
Verify that gas is flow-
ing to burner during
ignition try. Observe
gas meter for move-
ment during ignition
try (wait for about 30
YE S
seconds after calling
for heat).
Check for 24 VA C
between TH and GND
YE S
terminals on Ignition
Control Module.
SEE NOTE 1.
Check for 24 VA C
between TH and GND
terminals on Control
Board. SEE NOTE 1.
YES
Check for 24 VA C
between GAS termi-
nals on Control
Board. SEE NOTE 2.
Replace Control
Board.
Go to "INITIAL
TROUBLESHOOTING"
Continue to observe heater
for several minutes. Cycle
heater on and off several
times. Observe for delayed or
rough ignition, poor combus-
YE S
tion, premature extinction of
flame, evidence of boiling, or
operation of any diagnostic
LED. Go to pertinent trou-
bleshooting section if any
malfunction is observed.
NO
Replace Control Board.
YE S
NO
Ve rify that gas supply is open
all the way to Gas Va lve, and
Gas Valve is set at "on"
position.
Check for 24 VAC to Gas
NO
Valve terminals during ignition
try. (V oltage appears about 24
seconds after call for heat).
SEE NOTE 2.
Replace Gas Va lve with
identical part.
NO Fix wiring between TH and
YE S
GND terminals of Ignition
Control Module and Control
Board.
NO
Replace Control Board.
Fix wiring between GAS ter-
YE S
minals on Control Board and
Gas Va lve.
NO
NOTE 1: Vo ltage appears immedi-
ately after call for heat, and may be
on for only about 30 seconds.
NOTE 2: Vo ltage appears about 24
seconds after call for heat, and may
be on for only about 7 seconds.
YES