Baxi 105E hot water problem

[steve_smh]

When hot water is required the boiler fires up as normal. It heats up to the maximum 80 degrees and runs for 5 seconds or so before the flame goes out (DHW light remains on). The boiler then cools to 60 degrees before firing up again. This on off cycle then continues as long a tap is open. It also makes no diference where the DHW temp knob is positioned. The boiler is 6 years old and has worked fine apart from needing a circuit board 3 years ago.

Any ideas?

 

[gas4you]

Does the tap water come out hot as normal Or does it not get heated at all?

Could be a thermistor gone or possible pcb again if dhw stat doesn't control it.

 

[steve_smh]

Yes, the water gets hot (as hot as normal), but it cycles between hot & cold as the burner switches on and off.

Steve

 

[steve_smh]

Could be a thermistor gone or possible pcb again if dhw stat doesn't control it.

The DHW stat still controls the temp of the hot water.

 

[Vic Spanner]

The following will need to be checked

1. Is gas valve modulating (CORGI area)
2. Restrictions in plate heat exchanger

 

[gas4you]

Can I have my other half back yet poxi? I don't know what to do with all the money you are saving me

 

[Vic Spanner]

Can I have my other half back yet poxi? I don't know what to do with all the money you are saving me

Saving money don’t get me started...Just spent all afternoon shopping with the Gestapo (Its her Birthday tomorrow) after drunkenly saying last night I would take her shopping any where she wanted today..What a prat

 

[gas4you]

Amazing what a few pints costs us

 

[steve_smh]

Hi Guys,

For info, actual problem was a blocked DHW Heat Exchanger. Boiler heated up to max temp very quickly and the flame modulating was not enough to prevent the boiler overheating, hence it would cut out for a several seconds.