No hot water the boiler fires up to heat the water

[clint]

Hi, If anyone can give me a bit of technical advice why my halstead Ace boiler wont give out hot water. When I run the tap it fires up to heat the heat exchanger. I changed the diverter vale diaghragm a few months ago.

[jase158]

is it combi boiler?
are you gas safe registered?
did it work after you changed diverter valve?

[clint]

Yes it is a a combi boiler
No was corgi a few years ago
Yes worked fine
It stopped working after I changed a washer just before the heat exchanger as it was leaking.

[AWheating]

blockage?

[clint]

my understanding is there is two parts working to make hot water in a combi boiler. The first is a pump pumping water round in a circle from the heat exchanger to the secondary heat exchanger. The second is the cold water feed into the boiler passing through the secondary heat exchanger and out as the hot water.
I Pressume the first part is blocked?
When I put central heating on the the pipe from the heat exchanger to the secondary heat exchanger warms up

[armourer]

Is your central heating flow pipe getting hot when you turn on a hot tap?
I am thinking the plate heat exchanger maybe blocked and it will bypass to the central heating. (assuming your diverter valve is working OK)?

[clint]

Is it best to drain the system down refill with a flush run for an hour drain again and hope for the best.
or
Drain down and take the secondary heat exchanger out and try and clean.

[armourer]

You will have to remove the secondary heat ex and flush it through with a hose pipe.

[clint]

Thanks I'll get on to it monday