HW/CH off but upstairs radiators hot (pictures) - Help pls!

[itsmehere1]

Hi, So put the heating on the yesterday morning and I turned it off in the evening. Woke up in the morning and still the upstairs radiators were heated up. Now no matter what we do they are still on. Works absolutely great since we have been living here since April last year.

Standard boiler (non combi). Thermostat is on 0. Timer switched off. Maybe the diverter valve has gone. But we don’t know how to find the valve. Hopefully someone can make sense of it from the pictures and help please! x

Anyone? Hoping @pigletjohn is around!

The motorised valve is probably next to the hot-water cylinder.

It may be that your upstairs radiators are getting hot whenever the cylinder is being heated. This is likely to be due to wear in the valve.

A different fault would cause all the radiators to heat up.

It is possible that you have an old system with no motorised valve, and gravity circulation to the cylinder, especially if your cylinder is yellow, or copper-coloured with a red jacket. If your cylinder is close to the boiler this is not too hard to update.

Example valves
www.screwfix.com/search?search=Port+valve

There is probably a thermostat strapped to the side of the cylinder
www.screwfix.com/c/heating-plumbing/cylinder-thermostats/cat831450?cm_sp=managedredirect--plumbing--cylinderthermostat

I don't know if PJ is saying the same but more eloquently than me but our thermostat needed changing when our rads kept coming on randomly.

Thanks both.

We indeed have a red jacket water cylinder. What should we do in that case? Have asked for a gas engineer but he is busy atm.

Post some pics of the cylinder and all the things, pipes and cables around it.

Tried my best

Thanks

The Turbo thing is a shower pump and not relevant.

The brass system filter and the Grundfos pump are modern. Try to follow the pump pipe up and down and see where it goes. I think there is something beneath it.

The cylinder stat, if present, will be inside the red jacket, and will have an electric flex attached.

Thanks for the prompt reply Piglet 😊 what exactly am I looking for underneath the cylinder? I’m so sorry I’m terrible at this.

We had this OP - we had a little box in our airing cupboard with a valve/lever that moved to determine whether both the heating/hot water were in or just the heating. The valve was getting stuck so that whenever we had the hot water on, the heating would come on too.

We had to get the box replaced (sorry can’t remember what it’s called) but the engineer told us it’s a common fault as the valves seize up really easily. Even now we sometimes have to take the box off and manually turn the valve with pliers and some WD40 .

This is what ours looks like

Thank you @MindatWork seems like that may be the issue with ours too!

@PigletJohn could find these 2 valves? Behind the cylinder. Sorry about the state of it 🤯

Yes that's it. One of them opens to let the boiler pump hot water to the radiators, and one on them to the HW cylinder.

The are opened and closed by the room thermostat and the cylinder thermostat respectively. Each of them contains a switch. When they move to the open position, it turns on the boiler pump.

So one of them is probably jammed in the "open" position. Has the hot water from your taps been surprisingly hot?

It is possible to change only the motorised head, and this saves the effort of draining the water to change the brass valve (the two parts come apart on modern units) but you say the upstairs rads only are hot, which suggests the radiator valve is worn out, so you may have faults on both. If you are paying a plumber per call it might be more economical to change them both rather than one today and one next week, especially if the water needs to be drained which I think is likely.

Honeywell, and ACL Drayton, are probably the two best makes. You have one of each. There are also cheap makes. Mention to the plumber before he visits that they are 2-port valves. You can read this post to him (he may disagree with me).

If necessary, you can turn off the boiler at the wall switch at night or when you are away to save gas until it is repaired.

We’ve had this issue twice over the years. First time it was a stuck valve, second time it was a knackered room thermostat.

P.s. they often last around 20 years but I see your boiler and cylinder are much older than that. An old system will contain more dirt and sediment in the water which wears out the moving parts quicker and makes them more likely to jam. Ask him to empty the filter, preferably into a bucket to see how dirty it is.

Your Honeywell valve looks a lot older and shabbier than the Drayton.

Thank you @DotBall

Thanks so much @PigletJohn for your detailed reply. I will go through your reply once again to understand it, thankfully a plumber/gas engineer is coming tomorrow morning and I will explain your reply to him as well. Will keep you updated. thanks once again you’re a star! 🙏🏻