Isar : No Central Heating / Hot water OK
What display is on boiler?
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Boiler is in standby mode. Has no call for CH or DHW
If display still shows "0" contact installer |
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Boiler is running in pre-heat mode which ensures fast delivery of DHW. Pre heat occurs every 1h30m and lasts for approximately 1 minute. Pre-heat has priority over Central heating mode but should resume after completion. |
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Boiler is running in DHW mode. If no taps are open, check for dripping taps as this will cause the boiler to operate in hot water mode when not required and stop heating working due to hot water priority.
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If no dripping taps are evident isolate cold mains water (via stopcock) if boiler reverts to After isolation if D continues engineer visit required |
| C Codes when CH is not working |
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Boiler waiting to come on for CH, boiler thermostat is satisfied. External controls are calling for heat, if CH control knob not set to maximum turn up to call boiler to fire. If radiators are not getting hot, ask to check all radiator TRV's are open. If radiators are still not starting to get hot after short period of 5 minutes- Engineer visit required. This may eventually go to an overheat fault code of L9. |
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Boiler trying to run in Heating Mode - check as above |
or 
contact installer to correct water leak. (please note - can take 1 minute to stabilize temperature before returning to 0 or C)