No HW but boiler and pump running fine

[Mawdz66]

Hi Im new to this so here goes.

I have a conventional hw/ch heating system.

Im able have HW only CH only or both on at once with a mid port valve.

Recently all seemed to be normal but the tank water want getting warm

I found the HW thermostat on the floor, looked like someone had knocked it of the side of the tank(the kids!!)

The HW is the only thing on at the moment and ive checked the time, thats all ok , , so at 6.00 in the morning the boiler and pump fire up the 3 port valve is point to W for water , however the cylinder just isn't getting hot, the whether is going round another loop straight back to the boiler.

I have put the heating only on and that is working fine. I have put both of them on together the heating is working but not the HW. Ands Hw only isn't working

The slide on the front of the motorized valve is moving to where it should for each of the different positions.

My questions is , could it be the something as simple as the HW cylinder thermostat that is broken as this all seemed to happen form when I found it on the floor and the kids are always pulling blankets and things out of the airing cupboard had wondered if it had got knocked would that cause the problem .

Or is it something more sinister, like the motorised valve is playing up?
Any help or advice would be wonderful

The boiler is an old Glow worm fuelsaver mk2

many thanks for any help you can offer

 

[diamondgas]

Mawdz66, Hi

What make motorised valve is it? What colour top does it have? Could be simple as a dislodged actuator (top). Do the radiators heat up when on hot water only? Some actuators you can remove to check the cam. It too could be damaged and not turning the valve spindle but moving back and forth as it should do?

A bit more info might get us helping you out. However if you're not sure then get a professional to take a look

 

[cdodds2004]

pop the hot water on and hold the pipes either side of the valve, the one connect to cylinder should get hot, if the other one gets hot this could be your problem, make sure the cylinder stat is set at a decent temp!

 

[marleyco]

It's more than likely one of the above suggestions, could be possible you have auto bypass dodgey and water running through.

 

[Mawdz66]

Hi
The top is blue its a mid position actuator code BGMVSP-23. I took the motirsed unit off completely and tried to trun the spindle that sticks out of the copper valve, it would only turn one diredction anly about about an 1/12th of a turn. This small turn made no difference at all, all that happens is the radiotors get warm!!. I suppose its a case of buy the hole unit is it? thats the actuator and the 3port valve. When i had themotor off you could see the motor turning however the part that goes over the vlave spindle looked a bit worn as thought it had been against the valve as its only made of plastic. Any ideas would be great

 

[armourer]

It does sound like the valve body has jammed.

If it has it will be a drain down and replace the complete valve.
If you go for this route you might as well change it to a honeywell valve as they are more reliable imo).

I assume this is your valve?
British Gas BGMVSP-23 Actuator: Heating Controls Online

 

[Mawdz66]

It does sound like the valve body has jammed.

If it has it will be a drain down and replace the complete valve.
If you go for this route you might as well change it to a honeywell valve as they are more reliable imo).

I assume this is your valve?
British Gas BGMVSP-23 Actuator: Heating Controls Online

Yes thats the one is the valve the same size (dimensions) on the honeywell so i can just take the old one out and replace it with the honeywell , or would I need to alter the remaining pipework to getit ot fit do you think?

Thanks for your help much appreciated

 

[stevetheplumber]

mostly they are close enough in size to fit just watch that the treads on valve are same size if they are dont change the nuts

 

[Mawdz66]

Thanks very much I'll give it a go