Potterton Promax 15 HE Installation And Servicing Instructions page 39

No Pump Feed
Is
YES
Safety Thermostat
open circuit ?
NO
Is
YES
Fan Protection
Thermostat
open circuit ?
NO
Is
NO
thermistor resistance
between 0.5kΩ and
20kΩ ?
YES
Is
YES
combustion box door
seal damaged or not
in place ?
NO
Is YES
condensate trap
blocked ?
NO
Go to
IGNITION LOCKOUT
section of the fault
finding instructions.
Supplied By www.heating spares.co Tel. 0161 620 6677
Replace safety
thermostat (black)
Replace fan
protection thermostat.
Replace flow
temperature
thermistor (red)
Replace combustion
box door seal.
Clear blockage and
dry sensors.
15.0 Fault Finding
39