Problems with Htg/HW



Having problems with my central heating. There are a few strange things going on. I have a Worcester 40 Condensing boiler, 2 zone valves (1 htg. / 1 HW), Megaflo 210litre.

The boiler has been doing the HW fine all year and recently changed it to now do the heating. However it doesn’t seem to be performing like it used to.

1. The htg. will come on and off when it wants too! i.e. it doesn’t always stay to the preset times as I have set in the programmer. It can work ok and then other day come back to a cold house when it should be on, same in the morning!

2. Occasionally the heating will only work if I turn the HW off, strange cos they are separate valves (i.e. not 3 port). Although sometimes they will both work at the same time.

3. The heating will not come on, although the red light on the programmer indicates that the heating is ‘on’.

4. The boiler is whistling occasionally (not all the time), I have turned the temp down on the boiler as it was on max. (now 60ish deg C).

5. There are a couple of rads that don’t get hot, I have tried bleeding them but no air comes out, I turned all the rads off except the two in question and they did eventually get hot. Also tried bleeding the pump but no air seemed to come out, just a dribble of water.

6. The HW has worked ok all summer so I am not sure whether it would be anything wrong with the boiler (maybe the programmer controls?)

7. I f the programmer is not telling the ZV’s to open would this be causing the boiler to kettle? Which might be why its whistling occasionally, although there may be a bypass valve in the boiler?

I can’t seem to put my finger on the problems or if it’s a combination of all these things.

Hope I have managed to explain it ok.
:confused: :confused:
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