Halstead Ace High Boiler - Overheat and Lockout

[thellers]

We have a Halstead Ace High. Within about 45 seconds after drawing a substantial amount of hot water (two showers) the boiler will start spitting out steam and hot water droplets from the little rectangular hole at the top-left (I've taken the front plate off). It will then usually lock out the next time we draw hot water.

Had a guy in who said it was probably the little switch getting stuck in the 'on' position and causing the boiler to overheat. He was talking about a chrome pin that comes out of the big brass unit near the bottom and activates a relay-type switch inside a little plastic box (sorry, I don't know the proper names). We investigated this and it turned out not to be the case. In fact, the pin does go back (although slowly) and the boiler seems have successfully turned off, but then 45 seconds or so later, the spitting/steaming starts.

We've had an engineer in and he wants to replace the whole Diverter Valve at a cost of almost £300. With a baby on the way we could really do without this!! I know nothing about boilers but am generally pretty smart and handy, so would like to seek alternatives or at the very least understand more before forking out this amount of money.

Would anybody be able to suggest any alternative advice and even possible cheaper courses of action?

Your help is much appreciated!

Andy T

[Addy123]

The only thing I would suggest is to shop around for a number of quotes. I appreciate money is tight, but it's not worth trying to fix it yourself no matter how "handy" you are.

With a new baby on the way, you would never forgive yourself if you attempted to fix it yourself and something went badly wrong.

Do you have a service contract on it? Some companies will offer a discount on work if you then sign up for a service contract. That also then gives you peace of mind as once a year they give it the once over so you know all is ok.

[terence7556]

go on the gas safe website (use google) and type in your postcode to look for local engineers and get alternative quotes, preferably over the phone and compare costs.
from cold and selecting DHW, not CH does the boiler produce hot water in quantity and at a consistent temperature?within a minute or so from turning on does the heating flow pipe get hot or warm? on yours i think its the one on the r/h side, but check your manual.
this pipe should be cold and not get warm/hot but if it does then that is also an indication the diverter valve is passing.