Troubleshooting Chart - Millivolt - Hayward H150 Installation, Operation And Service Manual

SECTION 7. TROUBLESHOOTING
Heater Will Not Fire (Millivolt):
!
WARNING: For qualified service personnel ONLY!
This procedure assumes that the filter system is operating. Jumper wires are used for system checkout
only. Remove all jumper wires following system checkout or damage to heater may result.
Is the pilot lit?
Does the pilot stay lit when the
knob is released?
Is gas valve knob in "ON"
position?
Is system switch "ON"?
Is thermostat set higher than
pool temperature?
Jump across both "TH"
terminals on gas valve.
Is main burner lit?
Remove jumper wire from
"TH" terminals on valve.
Jump across pressure switch
terminals.
Is main burner lit?
Remove jumper wire from
pressure switch.
Clean the filter?
Check for adequate water flow
rate.
Readjust or replace pressure
switch. See section on
"Pressure Switch" under
Section VI.
36
NO
Check for inadequate gas supply, pressure, pipe size. See Gas Piping Sec-
tion. Check for blockage of pilot orifice.
YES
NO
Is tip of the thermopile
engulfed by the pilot flame?
YES Check thermopile output using
a millivolt meter as follows:
NO
Turn gas valve to "ON"
position.
YES
NO
Set system switch to "ON"
position.
YES
NO
Turn thermostat up.
YES
NO
Replace gas valve.
YES
NO
Remove jumper wire from
pressure switch.
YES
Jump across thermostat
terminals.
Does the main burner fire?
Remove the jumper wire from
the thermostat and replace the
thermostat.
NO
Check the orifice for blockage or
adjust thermopile.
YES
Remove both "TH" wires from the
gas valve and relight the pilot.
Does pilot burner stay lit?
YES
Attach millivolt meter to read
thermopile output.
Problem may be a bad wire or
low gas pressure.
If thermopile is about 500mV,
replace gas valve.
If thermopile is below 400mV,
check gas pressure or block-
age of orifice.
If output is still low, replace
thermopile.
NO
See page 37.
YES
NO