Halstead ACE problem

[ezzkazz]

Hi All,
I have a Halstead ACE HE35
This boiler is a nightmare and the worst purchase I made, but i cant afford to replace it so hopefully someone can help.

The common problem of CH fine but no hot water. Its intermittent though but right now it comes on then goes off after about 30 secs. I had the heat exchanger cleaned out already and Im guessing it wasnt that. The boiler guy came out and he fiddled with what looked like a squarish black box that he unclipped from somewhere, it may have had a needle in it (should have paid more attention!), he turned it upside down and the water was fine so he put it back and said something could have been stuck. Well its been ok for 2 months but now the same problem is back.

Can someone tell me what this black box is and if its likely to be the problem? He only switched the power off, not the water and he took it out from the bottom left of the boiler.
Thanks in advance.

 

[picasso]

More than likely to have been the dhw flow switch, although your problem could also be the dhw thermistor.

 

[ChrisR]

Yup the switches go intermittent.
BUt going off after 30 secs is classic for dirt somewhere. Not only in the secondary heat ex. They (hexs)do have to be really clean. Went to one which looked OK, having been cleaned recently with sometihng weak. After trying strong acid, the improvement was dramatic.
If the systems's at all dirty (this one wasn't, really) the symptoms come back pretty soon.
And yes the thermistors seem to drift off, and they cost more than they should - as do all their other parts

 

[ezzkazz]

The guy who came round first time cleaned the heat exchanger. He boiled it in vinegar . I have no clue if this was correct he was a bit old school.

I live in Lincs and there is no-one who i have found who knows about Halsteads. Ive even got in touch with Halstead to recommend someone and they said the dont know of anyone local to me, Im so sick of this boiler.

The water does sometimes stay on but its getting more frequent where it goes cold after a while so what would be the first thing I could try to replace or advise an engineer to replace? Is there a diaphragm in this model of boiler or should I go with the flow switch or something else? The heat exchanger is not something I could replace myself and to be honest I would rather get someone to fit a new boiler.