Halstead Ace High Boiler - Hot Water problems

[Useless@DIY]

Hi - we have a Halstead Ace High Boiler Combination for CH and HW - the problem we have, is the Hot Water is interrmittent. Whe turning on the HW tap, the boiler will fire up and run approx a minute, feeding hot water to the tap, but then cut out and runs cold, it will do this over and over. Makes fun for showers, you should hear her indoors scream when it goes cold !! - Can you elp please - I thought it might be a dirty flow switch, but I have to admit I know nothing about boilers - Please Help ! ....Thanks -Desperate Man and Cold Wet Wife .....

[dasherman]

I'm not a Corgi bloke but it could just need a good service.

[gasman]

I am a CORGI man and yes when did it last have a service sounds as if it needs one and especially the thermistor sounds like it needs replacing.

[Useless@DIY]

Thanks Guys, We will be ringing around first thing in the morning for a Service Man - its not been much fun having cold showers this weekend, and the kids are kind of turning blue in the bath - thanks for your comments.

[Kesmoco]

Hi, did the suggestion work? We have the same problem and the plumber seems to be struggling to figure out the answer. Thanks

[Useless@DIY]

Overall yes - the problem is possibly the heat exchanger, we have been told that the system does require a full flush out, and the heat exchanger (and the rest of the system) is possibly full of lime scale given we live in a hard water area - we still have the problem at the moment as the Plumber is booked in for Thursday this week, but we have learnt that if you turn on the hot water running slow, it will remain reasonable hot enough to have showers, and luckily the CH has never been affected, although we did notice last week (cold snap) it hasn't been as good as in the past. If your boiler goes into lockout through overheat likes ours has a few times when running full hot water tap, then it probably is a blocked heat exchanger , you will need to reset on front panel , and the reset under the left hand side for the thermostat to keep it going. Hope this helps you, will update once the plumber has been.

[Useless@DIY]

Happy Days again ! - the plumber came and conquered that old boiler .... best of all the bill wasn't that bad considering plumber rates. So the final outcome, as he said, full of lime scale, all it required was a clean out. He drained it down and flushed out the whole system - no parts required - we did not need to replace the heat exchanger which was great.
Im happy , I have just had a hot shower and it did not go cold once.

[Kesmoco]

Thanks for the info. We don't live in a hard water area so it's unlikely that limescale is the problem, however it might be general sludge that builds up in these systems. I saw the plumber tonight and told him about the Thermistor, but I shall ring him tomorrow and tell him your news. I'll post our outcome too.