heating zone valves

[Phillpiper]

Can I run a motorised zone valve and room thermostat from a 240V supply to control a single radiator when the heating is on?

Meaning the valve will be open when the room is below the temperature set on room thermostat without turning the boiler on / valve will close shutting off flow to a single radiator without shutting off the boiler?

Is this possible? Or are there any other ways of supplying a thermostat to a single room/radiator that doesn’t run the boiler?
(The boiler runs on a timer but one room is often too hot or too cold, I can’t zone the whole house)

 

[steadyon]

Why not just use a thermostatic radiator valve? E.g. Drayton TRV4

 

[Phillpiper]

Why not just use a thermostatic radiator valve? E.g. Drayton TRV4

Because I want to be able to set it to a comfortable and accurate max temperature and leave it, a trv doesn’t give the accuracy I’m looking for

 

[Last Plumber]

Because I want to be able to set it to a comfortable and accurate max temperature and leave it, a trv doesn’t give the accuracy I’m looking for

A good quality one like Danfos will but if you want to do it with a motorized valve you could do yes. Wire it from the load side of the central heating isolator so it is dead when the central heating is isolated from the electricity supply.

 

[SJB060685]

Is the radiator oversized? Have you tried shutting the lockshield valve down a bit to reduce the radiatos MWT (mean water temperature)?
A separate zone valve and room stat will work though.

 

[EvilDrPorkChop]

Digital TRV is your answer.

 

[Timmy D]

Bear in mind, room stats can have a few degrees sway. Check accuracy before you buy.

 

[Phillpiper]

Looking at a good one and have a zone valve already just looking for advice on how to do the wiring and if anyone has real world examples

 

[hometech]

Switch to a boiler that can operate low temperature CH flow. Then you can remove all TRV's and zones and heat the house as it should be, a house, not a series of interconnected rooms.

 

[EvilDrPorkChop]

Looking at a good one and have a zone valve already just looking for advice on how to do the wiring and if anyone has real world examples

It would be bad practice as Zone valves aren't meant to be held open for an extended period of time. What you're suggesting is just wiring a roomstat to a valve without any boiler control? If someone was to turn the stat up and leave it, for instance in summer the valve could be held open 24/7 and would quite easily burn out.

 

[Timmy D]

I assume you’re looking to power it from a separate supply to the boiler. This shouldn’t be done. Someone may assume the boiler and controls are isolated when I’m fact this valve wouldn’t be.

You should really run the supply from the boiler wiring centre.

Saying that, if you are going to run it from another source, use permanent pen and label it, so someone doesn’t get a surprise in the future.

Here you go:

 

[Phillpiper]

I assume you’re looking to power it from a separate supply to the boiler. This shouldn’t be done. Someone may assume the boiler and controls are isolated when I’m fact this valve wouldn’t be.

You should really run the supply from the boiler wiring centre.

Saying that, if you are going to run it from another source, use permanent pen and label it, so someone doesn’t get a surprise in the future.

Here you go:
View attachment 63133

To clarify, the box in the middle would be the wiring / power source?

 

[Timmy D]

To clarify, the box in the middle would be the wiring / power source?

In essence yes. It’s just a terminal block to connect all of the lives/neutrals etc. I should have included the power source.

Don’t electrocute yourself. Give us an update when you’re done 👍🏼

 

[Murdoch]

In essence yes. It’s just a terminal block to connect all of the lives/neutrals etc. I should have included the power source.

View attachment 63137

Don’t electrocute yourself. Give us an update when you’re done 👍🏼

do not do this

very dangerous and almost certainly a very good way to trip one or both rcds

 

[Phillpiper]

do not do this

very dangerous and almost certainly a very good way to trip one or both rcds

Care to explain or give further advice?

 

[Timmy D]

do not do this

very dangerous and almost certainly a very good way to trip one or both rcds

Please explain, I’m keen to learn. What’s the difference between the supply coming from a plug or fused spur in terms of tripping/danger?

 

[SJB060685]

I think he means if there is a neutral imbalance, as in you have separate lives and neutrals from an RCD. I'm not an electrician though so hopefully @Murdoch can clarify further?

 

[Murdoch]

Please explain, I’m keen to learn. What’s the difference between the supply coming from a plug or fused spur in terms of tripping/danger?

1. you should never have 2 seperate supplies to a single piece of equipment

2. doing what was suggested would almost certainly mean the supply coming from a seperate circuit AND probably a seperate RCD

just don’t do it

 

[ShaunCorbs]

It’s not on two separate supplies it’s off a plug top / fcu and isn’t wired back to the boiler hence no requirement for the orange or grey

Op you could use a motorised ball valve eg power open, power close

 

[Timmy D]

1. you should never have 2 seperate supplies to a single piece of equipment

2. doing what was suggested would almost certainly mean the supply coming from a seperate circuit AND probably a seperate RCD

just don’t do it

I get what you meant now about two supplies. In this case it’s just one supply.

It’s not on two separate supplies it’s off a plug top / fcu and isn’t wired back to the boiler hence no requirement for the orange or grey

Op you could use a motorised ball valve eg power open, power close

Good spot. Didn’t even cross my mind about not needing the grey, just thought, no need for a switched to boiler so omitted the orange.

Good idea with the ball valve.