Central Heating

Ideal Isar combi boiler problems - hardly any hot water

Anonymous user 14 March 2024 - 2.33 PM

Hello, I have a Ideal Isar combi boiler and I'm having problems. I have repressurised it using a filling loop last year after a loss of hot water from taps and a banging sound from the boiler itself. This seemed to fix the problem. However, when I tried to turn my central heating timer off as it approached summer, I noticed that the radiators were still running hot whenever the hot taps were used. I turned individual radiator thermostats to OFF, and turned down the dial to MINIMUM on the boiler. I then had the boiler serviced (same guy every year) and told him about the problem. Said it was a diverter valve, and would "settle down" now that the heating was off. It did stop, but I didn't have to have everything OFF the year before, so it worried me. Well, we had a cold day last week, and I turned the heating back on two radiators, and upped the dial on the boiler. Turned all to OFF again the next day when sun came back out. Now I'm having major hot water problems again. I get 10 seconds of hot downstairs, and just 3 upstairs before it runs freezing again. The display on the boiler says "d" all the while, so I know it knows to send me domestic hot water, but it just isn't. So I investigated the pressure, and I noticed that the bar had fallen below 1 and the boiler had started banging again whenever the hot tap was used. I went to repressurise it exactly as I had before, and the tap I turned to release the water into the filling loop began to leak as I turned it. I held a towel over it and persevered, and gradually got my pressure to 1.3. The leak stopped when I turned it off, but I'm still only getting 10 seconds of hot water before it goes cold again. The burner light comes on for a few seconds as I get the hot water, then turns off and the water is cold again. It's really frustrating, so any simple advice on what I should do would be greatly appreciated. Thank you.