IDEAL HE15 Installation And Servicing page 48

76 H......F........
Remove flame detection electrode terminal from PCB.
Is there continuity between the 2 terminal pins ?
Replace flame detection electrode
77 H.....4...... (FLUE THERMISTOR ERROR)
Can the fault condition be reset by switching
off the mains supply to the boiler ?
Check wiring for continuity from the
PCB to the flue thermistor
Check resistance, using a suitable multimeter
connected across the thermistor terminal pins.
o
At 25 C expect 9,700 - 10,300
o
At 60 C expect 2,400 -
o
At 85 C expect 1,000 -
Are thermistor values correct ?
YES
Replace PCB
78 H......n........
48
FAULT FINDING
(FLAME DETECTION - SHORT CIRCUIT ERROR)
YES
NO
Ohms
2,600 Ohms
1,100 Ohms
NO
Replace thermistor
(PHASE REVERSAL ERROR)
Check wiring to the boiler for
reversed live and neutral
NO
Replace PCB.
H9/L9 (FLUE GAS OVERHEAT)
Is the system filled and vented and all
isolation valves open ?
Is the pump operating correctly? Ensure
flow through system.
YES
NO
Check resistance, using a suitable multimeter
connected across the flue thermistor terminal
o
At 25 C expect 9,700 - 10,300 Ohms
o
At 60 C expect 2,400 - 2,600 Ohms
o
At 85 C expect 1,000 - 1,100 Ohms
Are thermistor values correct ?
YES
Inspect heat
exchanger for
blockage or damage
in the flueways.
Clean or replace as
necessary
mexico HE -
Fill and vent the
system and open all
isolating valves
pins.
NO
Replace thermistor
Installation & Servicing