No hot water

19 Nov 2008
Reaction score
United Kingdom

I have a Housewarmer 45 Electronic back boiler with Economy 2 gas fire and the hot water has been getting cooler over a few weeks, till now it's off.

Previously I have drained, flushed and filled again with inhibitor and I doubt there is air in the system.

I can understand that when the heating goes on the pump starts and the water get's hot (This happens ok), but what happens when the heating is off and the hot water is on, is there an electronic valve?

Cheers, Camerart.
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I think I've solved it myself!

I removed the immersion tank, put a hose pipe on each of the coil fittings and flushed the coil through and lots of very black water came out.

I also removed the plug for immersion heater, and inspected the inside. shook the tank and most of the fur on the coil fell off, a bit of wood knocked the rest off.

Then I put a pump on the 28mm pipework and flushed it so it also cleaned the boiler, and again loads of very black water came out.

Put it all back together and 'Hot water' again.

Hope this helps someone else with an old boiler.

Cheers, Camerart
Spoke too soon! I have been flushing (mains pressure) through different sections of the system plus more sentinel, and lots more black sludge came out.

The hot water works ok but the heating doesn't unless the hot water is on.

Can someone tell me: With a pumped heating/gravity water (no diverter valve) what tells the boiler to fire up when the pump starts?
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