ECR International Utica Boilers MAH-100 Installation, Operation & Maintenance Manual page 132

H
Overheat thermostat operated or
faulty.
CH system pressure less than
7.25 psi or more than 43 psi.
J
Ensure correct circulation of
the pump
K
Is there 120V at:
PCB connector x13 3 way valve terminals
Blue to Black central heating mode
Blue to Brown domestic hot water mode
See Wiring Diagram
2
Motor, 3 way valve
FAULT SOLUTION SECTIONS
Check for and correct any system
faults (water circulation).
Allow to cool. Continuity
across thermostat terminals
more than 1.5 ohm
Check Flow, Return,
sensors. See section 'D'
YES
NO
Check wiring and pcb connection at
connector x22 is there approx. 5 V
DC between the green and black
terminals
Check flow temperature sensor connections
YES
and position. Sensors swapped.
Cold resistance approximately.
1 OkO @ 77' F (CH sensors)
(resistance reduces with increase in temp.)
YES
Check 3 way valve cable.
Replace motor 3 way valve
NO
�I
� Replace safety thermostat
'---------------'
NO
Is E11 O is still flashing
Restore System Pressure
I
YES
Replace pressure sensor
• I
.I
NO
Replace PCB
I
YES
Go to section 'B'
Replace PCB
49
Replace PCB
I
I
Replace sensor
PN 240011430 REV. O [07/01/2021]