CH Thermostat issues

[AndyPRK]

So they have been using both brown and blue sleeving in the junction box to identify wires. That is good of them.

I increased the brightness of the junction box. And bottom right I can see 2 green/yellow wires sleeved blue and connected to a blue wire.
This matches an early photo of a working stat where g/y goes to N terminal.


Obviously if your stat isn't working, I assume it has been bypassed somehow to heat the room? either with the lever on the value or electrically. (what the one with the cover off?)
You now need to identify which silver valve does the troublesome room and then track the black cable back to the junction and see where its brown wire is connect to.

If you set all the room temps low except one at a time, and then see which pipe remains hot you can mark the valves to rooms
and then find the one you are looking for I guess


P.S if you look at the wiring, you will notice what is normal with your setup, is that the cable comes from the stat. The blue wire with brown sleeve is on the On signal and connects to the brown wire of the zone valve.

so for however many bedrooms? you have that work this should be the case

 

[jimmybobfixer]

So they have been using both brown and blue sleeving in the junction box to identify wires. That is good of them.

I increased the brightness of the junction box. And bottom right I can see 2 green/yellow wires sleeved blue and connected to a blue wire.
This matches an early photo of a working stat where g/y goes to N terminal.


Obviously if your stat isn't working, I assume it has been bypassed somehow to heat the room? either with the lever on the value or electrically. (what the one with the cover off?)
You now need to identify which silver valve does the troublesome room and then track the black cable back to the junction and see where its brown wire is connect to.

If you set all the room temps low except one at a time, and then see which pipe remains hot you can mark the valves to rooms
and then find the one you are looking for I guess


P.S if you look at the wiring, you will notice what is normal with your setup, is that the cable comes from the stat. The blue wire with brown sleeve is on the On signal and connects to the brown wire of the zone valve.

so for however many bedrooms? you have that work this should be the case

The valve that is uncovered is bedroom one. (faulty stat) The wire that has blue tape on goes to the Faulty stat.
Originally the house has had 2 core for stats(can see some snipped and replaced)

The faulty stat has 2 core into the junction box, however at the stat its 3 core(hence my assumption there is a join somewhere.)

bed 1 - 2 core at junction box , 3 core at stat
bed 2 - 3 core brown sleaving
bed 3 - 3 core brown sleaving
bed 4 - 4 core no brown sleaving( short run same room as the junction box)

Bed 1 either needs another single core feed or new 4 core wire run. Or a battery operated stat. The current stat is wired so it just completes the circuit permanently as soon as power is supplied from main timer.

Well that my understanding lol

 

[AndyPRK]

You could fit an old style 2 wire stat.
2 wire stat will be sufficient for one room and an improvement on what you have now.

https://www.ebay.co.uk/itm/124411641420

If it has a neutral terminal it should be for acceleration on this one.

 

[ericmark]

I look at the mess, and I know if it were my house, I would get some wiring centres and start re-wiring and getting rid of as many over sleeved wires that I could, but it is no easy task.

I would start with the motorised valves, as the colours of cores are fixed, it is about the only item where you can say I know what the orange wire does. Also @AndyPRK is correct the 2 wire thermostat will mean you don't need to use yellow/green as neutral or line.

The Flomasta 22199SX screwfix (6259G)

would likely work well at £27.56 not too expensive, batteries last around 2 years although I changed mine every your, and 6 programmed temperature changes, removing the need for neutral means could use existing cables over sleeving the blue with brown.

However it is clearly a big job, there is no real quick fix.

 

[AndyPRK]

I'm not sure I would advise anyone to rewire that unless they fully understand it, and not a DIYer! If its working, leave it alone, esp. as we are going into winter and a second lockdown

Personally I try to avoid batteries where possible

 

[ericmark]

I'm not sure I would advise anyone to rewire that unless they fully understand it, and not a DIYer! If its working, leave it alone, esp. as we are going into winter and a second lockdown

Personally I try to avoid batteries where possible

Yes must agree with you, time to look at it is spring, when you have time to get it sorted, we are looking forward to fire break ending on the 9th November, and had though we may go for quick break in caravan, but caravan stored in England, so that's now a non starter.

I have not found a way to power the central heating without batteries, I have 18 AA batteries powering my TRV heads, but the Nest Gen 3 thermostat is mains charged, still has back up batteries, but cross fingers will not need changing.

But last house had a DT2 thermostat for years, let one set of batteries leak so swapped it to a Flomasta 22199SX and cleaned up old DT2 which is still used as a clock and thermometer even if it does not power central heating. It is not batteries becoming discharged which is a problem, but batteries leaking, so 18 good quality AA batteries per year, should last 2 years, but not worth the chance.

 

[SUNRAY]

I'm not sure I would advise anyone to rewire that unless they fully understand it, and not a DIYer! If its working, leave it alone, esp. as we are going into winter and a second lockdown

Personally I try to avoid batteries where possible

Doing the controls work I have, I've been involved with replacing many tens, maybe a number of hundreds, of battery powered CH devices and converted to to wired.
On one development there were all sorts of problems with neighbours systems being intersynced and no amout of resetting/resyncing overcame the problem as the devices remembered the others.

 

[ericmark]

Thank you @SUNRAY I had not considered how wireless would work when a whole estate used the same devices. But reading what you say it is the wireless bit causing the problem, not being battery powered?

 

[SUNRAY]

Thank you @SUNRAY I had not considered how wireless would work when a whole estate used the same devices. But reading what you say it is the wireless bit causing the problem, not being battery powered?

It's both, the usual problem with batteries is leaking and going flat. In commercial or rental properties they are a big no-no AFAIC. Battery life in rentals seems to be well under a year for TRV. I write the date when I fit these things and quickly realised they frequently don't make the quoted time.

Oh and in rentals they do get tampered with, i suspect simply swapping to get free batteries then reporting heating not working. And often find them in wrong way round.