Hot water probs Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[richsherman]

Hi everyone, have got the Halsted Ace High combiboiler which i fitted about 4yrs ago. Its been running absolutley perfect until recently, when a problem has started with the dhw supply. When the hotwater tap is turned on the boiler fires up ok but then turns off after about 20 seconds thus causing cold water to come thro' but then fires up again after a few seconds, this happens constantly. Now if i turn the dhw temp control down to about a 1/4 it runs ok but the water is only just hand hot, if i turn the dhw temp control upto 1/2 way then it starts cutting out again. The central heating runs ok without any problems and the water pressure is between 1 and 2 bar. It seems like something is either overheating or some sensor is not working properly.
Any help from all them experts out there will be gratefully received.
Cheers Rich

[htg engineer]

Sounds like the hot water sensor needs replacing.

[richsherman]

Hi htg, thanks for you reply, have got the Halstead hand book, but can only find the dhw thermistor is that what you mean?
Cheers Rich

[htg engineer]

Yes - replace this shouldn't cost alot and it's one of the cheapest parts to replace. I am confident this will solve your problems. You'll probably find a build up of limescale on the sensor that may be causing the problems.

It should tell you how to change this in your user manual. Normally just need to turn off the cold water supply to the boiler, and open the hot taps to drain the hot water section.

Is this the first fault you've had in the 4 years ?
Halstead boilers have a reputation of being a cheaper make of boiler, with very poor reliability - produced for B&Q, wickes etc etc not normally a boiler i'd recommend.

[richsherman]

Hi htg, thanks for your info, have managed to get one today for a tenner and gonna fit it tomorrow all being well.
Yeh, i fitted this boiler 4yrs ago, i did all the central heating pipework myself using speedfit pipe and fitting absolultey brilliant, bit costly mind you, but worth it. then got a corgi gas fitter to come and do the gas supply and commision the boiler and touch wood, uptil now its been fine. The handbook shows an exploded diagram of all the parts so it should only be a 2 min job :lol:
Will let you tomorrow nite if alls well.
cheers rich

[richsherman]

Hi htg, well i've fitted the thermistor and guess what!!! complete failure it's still doing it. Have looked at the setup and come to the conclusion it can only now be the pcb. If the ch works ok it can't be anything to do with any pumps or valves or anything, but only the pcb acting up. Unless you have any other ideas, it looks like a new one after xmas.
thanks for your input anyway
cheers Rich

[htg engineer]

I suggested the hot water sensor, as it is normally the culprit. Plus it is the cheapest and easiest part to replace.

The plate heat-ex could be choked, If the heat isn't getting away from the boiler quick enough this will cause the burner to cut out as it will think (and rightly so) it has reached the desired temperature.

You could remove the plate heat-ex and celan it out, there may be a build up of limescale in it. Section 9.13 in your manual.

Without seeing the boiler I am only able to give you ideas as to what may be the problem, through experience of working on other boilers. If you are wanting it repaired quickly and with accurate diagnosis you'd be better off getting a Heating engineer to take a look.

[richsherman]

Hi htg, right, ok thanks for that idea. Will give it a go tomorrow.(last attempt!!) Being a telecomms engineer, i'm not to bad at figuring a few things out for myself, thats how i like to learn about solving different problems, but when it comes to things like this, i can get so far, (with a bit of help!!) and then as you say will have to get the experts in.
Will let you know tomorrow nite what the outcome is.
cheers again Rich

[richsherman]

Hi htg, well i've had the heat exchanger out and to my surprise it was quite clean no sludge or any build up at all. There was a bit of crap in the bypass pipe underneath but it was only a few bits. Got it all back together and its still cutting out but not as bad, so if it gets any worse (the wife wont let me play with it anymore " you'll knacker it up for xmas" syndrome), its gonna be one of you chaps down for a visit methinks.
Anyway thanks again for taking the time and your input, have a good christmas and a happy new year
Cheers Rich