Baxi 105e Combi Saga Continues

[Jennywrens]

HI

Thanks for previous replies - I am hoping you are going to tell me what I need to hear!! - Scenario -

Boiler been switched off completely all night.
Switch on boiler to CH and HW mode, radiator light comes on, heating on, perfect working order.
Use some hot water for a shower
CH light goes out, giving rightfully so HW precedent
BUT, after HW has been used, the CH light does not come back on, no hot rads, AND the water just keeps boiler over

Is this a valve problem and if so, how do we fix please?

Many many thanks - we have been trying to sort this out for weeks.

 

[picbits]

I had this on a Gloworm combi boiler.

The DHW demand switch was sticking. I unstuck it and it worked fine for a few more months then the problem came back. Turned out to be a weak diphragm on the DHW demand switch. It would let the switch turn on when water was called for but did not turn back off causing the boiler to overheat.

 

[Agile]

It sounds more like a failed PCB to me but can also be other things as well.

Unfortunately you have started up a new thread so I cannot read the background.

Could you cut and paste this into the previous thread and ask the Mod to delete this one. Then we will be able to read the whole history and give more detailed advice.

If the DHW switch was staying on then the boiler would heat the rads which is obviously not happening in this case.

Tony

 

[picbits]

If the DHW switch was staying on then the boiler would heat the rads which is obviously not happening in this case.

Tony

On mine when the DHW switch got stuck on it signalled the boiler to keep the diverter valve in the hot water position.

As there was no flow through the hot water pipes (DHW) the boiler kept heating the water that was in the heat exchanger. Freeing the switch made the boiler switch the diverter valve back and the central heating side then warmed back up.

 

[ChrisR]

WHole diverter sticking in HW position, isn't it?

 

[picbits]

WHole diverter sticking in HW position, isn't it?

If that was the case I wouldn't expect the boiler to boil over unless it was on the CH setting as well.

i.e. if the CH is off and the boiler keeps running after the hot water tap is turned off I would suspect a dodgy flow switch.

If the CH is off and the boiler turns off when the hot water tap is turned off then I would suspect a sticking diverter valve.

If the CH is on and the boiler overheats when the hot water tap is turned off then I would susptect the sticking diverter valve.

 

[baxpoti]

You haven't answered the questions in your original thread

The answers to the questions may give us more of an idea as to the root of the problem

 

[Jennywrens]

It sounds more like a failed PCB to me but can also be other things as well.

Unfortunately you have started up a new thread so I cannot read the background.

Could you cut and paste this into the previous thread and ask the Mod to delete this one. Then we will be able to read the whole history and give more detailed advice.

If the DHW switch was staying on then the boiler would heat the rads which is obviously not happening in this case.

Tony

how do I find my previous thread please? all I said was that the central heating would not come on AT ALL, but we didn't actually know until this morning after the boiler being off all night, that it would come on cold, but it would not switch back after using hot water. - That has isolated quite a bit as no-one knew why on earth the heating would not come on at all - as above, we know it does now, but just doesn't switch back

Thanks, Jenny -ps what is DHW? doh!

 

[clf-gas]

It sounds more like a failed PCB to me but can also be other things as well.

Unfortunately you have started up a new thread so I cannot read the background.

Could you cut and paste this into the previous thread and ask the Mod to delete this one. Then we will be able to read the whole history and give more detailed advice.

If the DHW switch was staying on then the boiler would heat the rads which is obviously not happening in this case.

Tony

how do I find my previous thread please? all I said was that the central heating would not come on AT ALL, but we didn't actually know until this morning after the boiler being off all night, that it would come on cold, but it would not switch back after using hot water. - That has isolated quite a bit as no-one knew why on earth the heating would not come on at all - as above, we know it does now, but just doesn't switch back

Thanks, Jenny -ps what is DHW? doh!

Previous //www.diynot.com/forums/viewtopic.php?p=690814#690814

DHW Duty Hot Water

 

[namsag]

removed

 

[baxpoti]

dhw - Stands for Domestic Hot Water


Is your boiler a 105e or a 105e instant?

 

[namsag]

Baxi looking at the other thread i would say she has an instant

 

[Jennywrens]

Baxi looking at the other thread i would say she has an instant

yes, you are quite right it is a 105e instant

thanks, Jenny

 

[Jennywrens]

WHole diverter sticking in HW position, isn't it?

If that was the case I wouldn't expect the boiler to boil over unless it was on the CH setting as well.

i.e. if the CH is off and the boiler keeps running after the hot water tap is turned off I would suspect a dodgy flow switch.

If the CH is off and the boiler turns off when the hot water tap is turned off then I would suspect a sticking diverter valve.

If the CH is on and the boiler overheats when the hot water tap is turned off then I would susptect the sticking diverter valve.

The boiler overheats when in CH and HW mode - CH working, hot water used, hot water tap turned off, CH does not come back on, boiler overheats

 

[picbits]

What happens when CH is turned off and DHW is used ?