HTP MC120 - Manual (Page 67)

67
LP-171 Rev. 4.10.14
F09
No flame detected – The
heater will make three
attempts at ignition before
the control goes into this
lockout condition. *See
spark electrode detail.
1. Watch the igniter through the observation window provided.
2.
If there is no spark, check the spark electrode for the proper ¼” gap by holding two quarters together and
sliding them through the gap.
3. Remove any corrosion from the spark electrode and flame rectifier probe.
4. If there is a spark but no flame, check the gas supply to the heater.
5. If there is a flame, check the flame sensor.
6. Check any flue blockage or condensate blocks.
F10
Loss of flame signal – The
heater will relight 4 times
before the control goes into
this lockout condition. Will
reset in 1 hour.
1. Monitor the gas pressure to the unit while in operation.
2. Assure that the flame is stable when lit.
3. Check to see if the green light on the display module is out while the heater is running.
4. If the green light doesn’t come on or goes off during operation check the flame signal on the status menu.
5. If the signal reads less than 1 microampere, clean the flame rectifier probe.
6. If the flame rectifier probe continues to read low, replace it.
F11F
False flame signal – The
heater will lock out if it
senses a flame signal when
there should be none
present.
1. Turn the gas off to the unit at the service valve.
2. If the flame signal is still present replace the igniter.
3. If the flame signal is not present after turning off the gas supply, check the gas valve electrical connection.
4. If there is no power to the gas valve, remove the valve and check for obstruction in the valve seat or replace
the gas valve.
5. Turn the gas on at the service valve after corrective action is taken.
F13
Combustion fan speed out
of tolerance – The
appliance will lock out if it
senses that the fan speed
is not at 70% the expected
speed for more than 60
seconds.
1. Check the combustion fan wiring.
2. Replace the combustion fan.
3. Replace the control board.
PP
The control has been
programmed by a
technician or the factory.
After programming, the
control is left in a locked out
mode.
Press the RESET key for at least 1 second to begin use of the control.
F31 Parameter Memory Call factory for further assistance.
Table 15
Resistance Tables
PART 15 – MAINTENANCE
A. MAINTENANCE PROCEDURES
Periodic maintenance should be performed once a year by a qualified service technician to assure that all the equipment is in safe
efficient operation. The owner can make necessary arrangements with a qualified heating contractor for periodic maintenance of the
HEATER SENSOR
(7250P-059)
INDIRECT SENSOR
(7250P-325)
HEATER AND INDIRECT
TEMPERATURE ( o F)
RESISTANCE (ohms)
32 32550
41 25340
50 19870
59 15700
68 12490
77 10000
86 8059
95 6535
104 5330
113 4372
122 3605
131 2989
140 2490
149 2084
158 1753
167 1481
176 1256
185 1070
194 915
203 786
212 667
OUTDOOR SENSOR
(7250P-319)
OUTSIDE TEMP.
( o F)
RESISTANCE
(ohms)
-22 171800
-13 129800
-4 98930
5 76020
14 58880
23 45950
32 36130
41 28600
50 22800
59 18300
68 14770
77 12000
86 9804
95 8054
104 6652
113 5522
Table 16
Table 17