ECR International Utica Boilers MAH-125 Installation, Operation And Maintenance Manual page 112

Temperature sensor faulty.
D
Check correct location and wiring
YES
Temperature sensors faulty.
Cold resistance approximately
°
10k0 @ 77 F (CH sensor)
°
20k0 @ 77 F (Flue sensor)
(resistance reduces with increase in temp.)
E
Gas at burner
Check wiring & PCB - X36 and X2 connector.
See Wiring Diagram.
F
Check and correct if necessary
1. Inlet gas pressure
2. Ignition electrode and lead
3. Electrode connection
4. Spark gap and position
5. continuity between burner and
earth
6. Condensate trap blocked
G Check the gas supply pressure:
For Natural Gas greater than
1.
3.5"wc
For LPG greater than 8"wc
2.
Check and correct if necessary
1. Flame sensing electrode position
2. Flame sensing electrode and lead connections
3.Recirculation of flue
4. Calibration
(CO2 values - see instruction)
FAULT SOLUTION SECTIONS
i
, _ _
Ensure gas is on and purged
YES
Check wiring.
f-----+
See Wiring Diagram
N
o
_ _ �.,, Replace sensor
_
.----------------, NO
Check the resistance of the
coils:
Pin 1 and 3 = 20 - 30 Ohm
Pin 2 and 4 = 60 - 70 Ohm
H
Replace flame sensing electrode or gas valve
42
Replace gas valve
YES .--------- --,
Replace PCB
J
I
NO Replace PCB
PN 240011430 REV. M [06/30/2019]