DIY Doctor UK DIY Forums

Hi

I have a Halstead ACE boiler. :?
After long draw offs of hot water the boiler will lock out due to overheating. I have recently changed the secondary heat exchange to resolve another issue but can't be sure why the boiler is now overheating.

I suspect that after a run of hot water, the boiler is supposed to divert the remaining hot water into the central heating system so that it doesn't remain in the boiler but this doesn't happen.

Can any one tell me if my suspicion is correct? What controls it?
Or what the problem is if I'm way off base?

Hi,

Diverter valve, but could be other things tho

Hi Steve

Thanks

I can't find a diverter valve in the manual :shock:

Is it known as something else?
Is the flow switch the same thing?

Any help still appreciated!! :?

Do you have the manual?
If not contact the manufacturer - they will email it.
Follow the fault finding guide if you are going to attempt the repair.If not get an RGI by recommendation.

Hi Setve,

Yes I have the manual

The fault finding section for hot water is for checking the start up procedure and ignition sequence. Both of which work fine.

It doesn't however explain what should happen when the demand for hot water stops.

The only reference it makes to the system going into overheat lock out is to check the secondary heat exchange for debris and replace.

However, this problem has started happening since replacing the secondary heat exchange. It's difficult to know if it would have happened before replacing, as I didn't have hot water.

Could be diverter sticking/ microswitch get a good RGI on the case