Baxi 105e fault

[andy74rew]

I have a Baxi 105e and several times a day it will kick in (fire up the boiler but not the pump). It'll just sit there burning gas, heating the water in the boiler, not pumping with no demand for hot water or central heating.
The raidiators will eventually start to heat up as the water heats up.
This can be stopped by turning on and off a hot tap, it will then start again a bit later on.

Has any one got any suggestions/experiences with this?

Thanks

Andrew

 

[Dan Robinson]

Can't remember if these have a preheat.


If you run a bath do any rads start to warm up?

If the answer is yes to both, then you have a faulty diverter valve.

 

[45yearsagasman]

The 105e instant does have a preheat. If your boiler is this model then the preheat can be turned off on the control panel.

 

[andy74rew]

There isn't a per-heat function. The boiler sitting there with no demand at all will just kick into life and just start burning gas for the hell of it. The pump doesn't start. There aren't any fault codes.

 

[stew1]

the symptoms you describe should be not be possible the pump is proven by a microswitch which must be made before the boiler can ignite

 

[Agile]

It sounds tome like an intermittently faulty DHW demand switch!

Tony Glazier

 

[Dan Robinson]

sounds to me like the op is making assumptions.

if the burner is firing for more than a few seconds without the pump running the boiler will be banging and clattering. the rafs wouldn't be heatimg up, amd it will overheat giving the respective lockout indication.

 

[gas112]

The pump will be running otherwise the boiler would sound like someone hitting it with a hammer .
Choice of 2 faults microswitch or pin sticking on divertor after HW demand or the in built frost stat is faulty