British Gas Up2 thermostat not switching off even in OFF mode!

[tealife]

Really need help as getting burnt with hot water this summer. For over a month now my British Gas Up2 thermostat is not turning off (pic below). This is supposedly resulting in super hot water even with a slight flic to the hot side of the tap. Shower is also extremely hot (if leaning even slightly on hot side of tap) making showers unbearable.

The heating system is also connected to GRUNDFOS ALPHA2 (pic below). I don't know what it does but I've put it to the lowest setting possible, hoping it is helping keep the heating down.

I saw an old thread exactly on this topic but it didn't have a resolution, so any advice would be really helpful. Old unresolved thread -

Old British Gas Up2 thermostat doesn’t turn off heating

Hi, I have British Gas thermostat UP2 for 10years, worked very well. I turned heating on yesterday as it was a bit cold. The hot water is in timer , but the heating advance and once button didn’t work , only select the ON button, the light is on and heating comes . But the heating won’t turn...

www.diynot.com

 

[JohnD]

The thing in your pic is not a thermostat. It is a timer-programmer. It is probably not the cause (unless you have recently fitted it, wired wrong).

Look for your three-port valve.

Probably close to the pump.

They often last around 20 years.

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[Deleted member 267285]

Yep, as above you have a 2 channel programmer which is set to off, not a thermostat. Look for a motorised valve or 2. Check the immersion heater isn’t on, if fitted.

 

[JohnD]

BTW, in your second pic, which way is "up?"

The Spirotech filter works by particles falling, under gravity, to the bottom of the collection chamber. Has yours been fitted long?

 

[tealife]

The thing in your pic is not a thermostat. It is a timer-programmer. It is probably not the cause (unless you have recently fitted it, wired wrong).

Look for your three-port valve.

Probably close to the pump.

They often last around 20 years.

Port Valve - Search Results | Screwfix

Order Port valve at screwfix.com. Free next day delivery available. Buy online & collect in hundreds of stores in as little as 1 minute. Free returns. 30 day money back guarantee.

www.screwfix.com

Thank you, i think i've found the valve (pic attached), although how can i know if it's gone faulty? thanks.

 

[tealife]

BTW, in your second pic, which way is "up?"

The Spirotech filter works by particles falling, under gravity, to the bottom of the collection chamber. Has yours been fitted long?

I turned the image upside down when posting to read the letters

 

[JohnD]

Thank you, i think i've found the valve (pic attached), although how can i know if it's gone faulty? thanks.

most likely the older of the two. Hot water from the boiler is pumped in one end, the thermostat should drive a small electric motor that opens and shuts the valve. When the valve is in the open position, it mechanically trips a switch that turns the pump on. If there is a fault, the motor does not close the valve and turn the boiler off. This is probably what has happened. It can be a wiring fault, but in your case I think probably the mechanism under the cover. Although on some models you can replace the motor section only, yours looks very old and the moving water parts are probably worn out as well, so change the whole thing. Repair the leak as well.

When the valve is open, the pipes will both be hot when heating is working. When closed, hot water will not flow through it so the pipes will not be hot (may be warm from conduction). this can tell you if one of them is working correctly.

I don't do this often enough to describe diagnosis from memory. You can test the electrical connections with a multimeter to see what they are doing

 

[tealife]

A new issue cropped up this morning. I switched off the back boiler from mains and when plugged back in, the GRUNDFOS ALPHA2 now shows flickering LEDs, not sure if this is a new issue with the GRUNDFOS or caused by the original issue.

 

[JohnD]

Don't know. If the leak has got into the electrical connections inside the motor box, it might have undesirable results. You can see the old rust on the (once galvanised) casing so it has been going on a long time.

edit
BTW the Grundfos is the circulating pump, and quite modern,

 

[Deleted member 267285]

Unless you took that photo of the valves with a demand on, then I’d say it’s the Drayton, as it’s slightly open to port B. Also the wiring coming out if that white boxes, possibly wiring center is not the best practice.

 

[JohnD]

the drayton looks quite new, so there is a possibility of a wiring error.

 

[dilalio]

Think you're better getting someone in as you have a few issues and very little knowledge or experience.