I have a combi boiler that heat up my radiators and also heats up water as you need it by turning on any hot water tap (faucet), yesterday I noticed that it wasn’t heating up the water properly – the water temperature would start out at 30 degrees it would then climb to about 55 degrees for a couple of minutes before falling back to 30 degrees, it would continue to climb and fall, I called the company that is contracted to look after and repair my boiler but the man that came out said that since the water tempreture rises there was not a fault with it, I pointed out that it could cause problems if I take a shower and the changing temperature had never happened before, I then asked if maybe there was a fault with one of the sensors – he said yeah sensor maybe its that I will order you a new one, I am no expert and the engineer didn’t seem like an expert either so does anyone know if that does sound like a sensor problem – it’s a vokera boiler
I would get them to send out another engineer (one who knows what they are talking about) and there are tests which can be carried out. the heat exchanger could be getting furred up and so the water heats up but can not pass through so the burner lowers the temperature drops the burner raises and so on. I only know this because I had a similar issue which the boiler man sorted and explained it to me (because I'm nosy) but he tested the sensors and said they were fine then he checked the distribution valve and exchanger and found the exchanger to be the issue, 25 minutes later it was all done and dusted and we had hot water etc again without problems
I have a combi boiler too, it could be the pressure building up inside. Have a look for a lever which can be twisted to release the pressure. Turn boiler off when you do this though
