boiler would not stop and upstair Radiators Warm When Water only selected

[sam250]

Hi there, some issues with my central heating system. I would like some advices before I have it repaired by a plumber.
I have a British Gas 330+ boiler installed by BG 6,7 years ago. (I was told it was re-badged from GlowWorm). The timer is a BG Up2 model.
Anyway, recently we found that
1. for the central heating, even if the timer is switched off automatically (meaning on the timer it is "off", i.e. the red light is off), SOMETIMES the boiler is still running for the central heating, and under this circumstances even the hot water is getting extremely hot too (meaning hotter than when hot-ted by normal timing). We have to manually switch the power supply (by the power switch socket) off then turn it on again after a few seconds. Then the boiler is off.
2. We then for the central heating tried to skip on the timer the "timed" and "once" option, just use its "on" and "off" manually. It seems to work, but recently we found that it SOMETIMES would not work too, the boiler would not stop even when on the timer it is switched off. We need to turn the power off again to force to stop. However the hot water part, which we always use the timer, works OK.
3. Yesterday evening was relatively warm and we did not switch on the central heating. However we found when the timer is on (automatically by the timer) for the hot water, the up-stair radiators were getting warmer too, although the ground floor radiators remain cold.

Many thanks
Sam

 

[picasso]

Sounds like one of your valves is sticking (google Honeywell 2 port for what they look like) and is the rads heating upstairs a new problem with just the hot water on a new problem ?

 

[sam250]

Many thanks Picasso.

I searched and found Honeywell 2 port on the web. But I must admit I don't understand it completely. So it has nothing to do with the timer? I thought that the timer would cut off the power!

Regarding the heating Rad, funnily enough, it did not happen today so I will wait and see. I listed the two together as I was wondering if they are connected. But yesterday we did not use the CH and that was why I found it. Normally when HW is on the CH is on already and I wonder if this is the reason I did not find it and I am still not certain as yet now. Also, why only the up-stair ones are heated? It seems to cool down again once the HW is off. HW just runs a short time and the Rads were not too hot. As it only happened once I will wait to see if it happens again tomorrow.

I attach two photos here. I guess the first one is the port/valve? what is the 2nd one for?

Regards

 

[picasso]

The second one is your three port valve, what you have described sounds like the three port is playing up, get the head changed and see if it cures both problems.

 

[dilalio]

+1 for @picsasso

First pic is your circulation pump.
Second is your midport valve which is motorised to divert heat between Hot water cylinder; central heating, or both.
The head contains an electric motor which can wear out and it can fail electrically as it has a microswitch. The valve that it operates can also become stuck due to wear and/or blockages in the water system that it controls.

 

[stem]

I searched and found Honeywell 2 port on the web. But I must admit I don't understand it completely. So it has nothing to do with the timer? I thought that the timer would cut off the power!

Yours is a 3 Port valve; and as has been stated, it does indeed contain a switch that operates the boiler. However, it is different from the 2 Port valve, in that the switch in the 3 port valve is powered from the programmer, via the room thermostat. (if one is fitted) Therefore, if the heating is switched 'off' at the programmer, the boiler would also go off as power is no longer supplied to the switch.

Although your valve is labelled as a British Gas product the valve is actually a re-badged Drayton MA1

 

[Mottie]

I had a similar problem once with a 3 port valve. With the heating on, the hot water would get scalding hot. The valve was not completely closing off the hot water circuit so it just kept getting hotter. A new valve cured it. Sounds like the OP has the same problem, only in reverse.

 

[stem]

I had a similar problem once with a 3 port valve. With the heating on, the hot water would get scalding hot. The valve was not completely closing off the hot water circuit so it just kept getting hotter. A new valve cured it. Sounds like the OP has the same problem, only in reverse.

A valve not seating properly wouldn't explain why the boiler was still running when the programmer is switched 'off'

SAM250 when the 'fault' occurs (ie the boiler still runs) happen when the heating and hot water are both 'off' at the programmer? Also, was anything moved or disturbed before the 'fault' appeared? Any components changed? Or did it just appear?

 

[Mottie]

A valve not seating properly wouldn't explain why the boiler was still running when the programmer is switched 'off'...QUOTE]

Ah, right. I only had my problem when the boiler was switched on and running the heating.