My totally illogical combi boiler...

[alfiebeagle]

My totally illogical combi boiler... it's driving me nuts. Hope one of you guys can point me in the right direction as to what needs doing.

I have a Baxi Combi Instant 105e, and having already perused this forum I see this model makes a few appearances

What's happening is, if we have the dial set to hot water only, we get a few hot radiators too. Not great in the summer so at the moment, we're having to switch the boiler off until we need to use the shower etc. A total pain. If we have the setting on heating and water, the water doesn't really get hot enough but the heating works fine.

Should I be taking advantage of the boiler scrappage scheme or is there any hope?

Thanks for any advice you can give.

 

[gas_man_gaz]

most likely to be ya diverter valve passing, turn ya hw thermostat on the boiler to 0 (turns the pre-heat off) this way they will only heat up wen ya running the hw tap.

boiler isn't eligible for the scrappage scheme.

 

[linkyplumb]

I take it you mean that when the dial is set at hot water only, then the radiators only warm up when you are actually drawing off water, ie the boiler is firing.

Sounds typical of a faulty diverter or pressure differential valve diaphragm.

Easy repair and not too expensive.

If you are saying that the rads are warming up without drawing off hot water, then that is a different issue.

Graham

 

[alfiebeagle]

gas_man_gaz - Thank you. I'll try setting the preheat to zero to see if that helps (with one of the problems anyway).

linkyplumb - Thank you also. To clarify the problem, when the dial is set to hot water only, even after we've finished drawing the hot water, if we've forgotten to turn the boiler off again, the radiators stay on.

The more frustrating problem is when both heating and water are on, when one jumps in the shower on a cold morning, the water is lukewarm - and that was a prevalent problem last winter - not to be repeated (hence why I need to get this problem sorted before the advent of colder weather).

 

[Agile]

Thats a different problem. It sounds like a failed DHW demand switch.

They come with a lot of wiring harness which takes a while to replace and involves opening the PCB housing.

I have seen them done with a chocolate block connector in 10 minutes.

Tony

 

[alfiebeagle]

Guess I'd best call out one of you professional guys then! Thanks for the advice, Agile.

 

[gas_man_gaz]

Thats a different problem. It sounds like a failed DHW demand switch.

They come with a lot of wiring harness which takes a while to replace and involves opening the PCB housing.

I have seen them done with a chocolate block connector in 10 minutes.

Tony

on the instant with the dial set to hw but the preheat left on, the boiler will stay on n heat the rads during preheat. with the hw being poor and the ch coming on without demand it suggests the diverter. if it fires without demand (with hw stat turned to 0) then it could be that hw micro-switch is stuck on but is normally the pin that is stuck out not the switch. but before doing anything i would check which neon is lit, preheat - hw demand or ch demand and it will tell ya for sure