Boiler Thermostat

[FoxyChris]

I want to replace out ancient timer for the boiler. I've taken it off to have a look at the wiring and it's just a simple inline neutral switch.

From what I can see the timer is wired to the Live, neutral and Earth. The live and comm 1 are then connected with the neutral wire going to the boiler connected to on 4.

Can anyone tell me where I can buy a new digital thermostat? I don't need any timer facility just something I can raise and lower the temp to control the boiler. At the moment I have to set the timer or keep getting up to switch it on! All the radiators have TRVs on so all I need is a central thermostat.

 

[EFLImpudence]

It is NOT a neutral to the boiler; it is a switched live.


A neutral is the conductor that completes the circuit back to the supply after the load .
Wires can be anything we want them to be. They do not know what colour they are.

 

[PrenticeBoyofDerry]

https://www.google.co.uk/search?q=d...j4&sourceid=chrome&espv=210&es_sm=93&ie=UTF-8

 

[EFLImpudence]

You will require a two-wire thermostat which doesn't need a neutral because there isn't one.

Either mechanical or

a battery operated one.

 

[FoxyChris]

Thanks, makes perfect sense. The black wire must be a live but whoever put it in just used the wrong colour.

 

[Taylortwocities]

The colour of the wire is the colour of the wire.

If the black wire is a switched live then it should be sleeved red, but this is a technique only employed by electricians who know what they are doing.

Regretably this did not include the installer of that heating system.

 

[winston1]

Why is the title, and why are we talking about boiler thermostats? This is a timer.

 

[FoxyChris]

Because if you read it properly I have a timer now and want to replace it with a thermostat.

 

[winston1]

You can't simply replace a timer with a boiler thermostat. A boiler thermostat is built into a boiler and responds to the temperature of the circulating water.

Perhaps you mean a room thermostat!. Well you don't need one as the radiators have TRVs.

 

[EFLImpudence]

You need something to stop the boiler cycling all Summer.

 

[FoxyChris]

Ahhh, I see what you mean. Yes, we want a room thermostat to control the central heating. Although the radiators have TRV we'd still like to be able to set a master temp overall.

 

[winston1]

You need something to stop the boiler cycling all Summer.

It is called a switch, and I assume it has one.

 

[EFLImpudence]

No one is going to switch off the boiler every time all the TRVs are closed.

One room - living room - should be left without a TRV and fitted with a thermostat so that when at the required temperature the heating system and the boiler is completely off.
This saves wasteful cycling and allows the system to work should there be a cold Summer day or period.

 

[ricicle]

You can replace the existing timeswitch with a programmable thermostat as long as it is in suitable position (so it can monitior true room temperature ie not above a radiator or out in the garage !)

 

[winston1]

No one is going to switch off the boiler every time all the TRVs are closed.

One room - living room - should be left without a TRV and fitted with a thermostat so that when at the required temperature the heating system and the boiler is completely off.
This saves wasteful cycling and allows the system to work should there be a cold Summer day or period.

Some systems have TRVs everywhere and use the boiler flow switch for control. No flow, no firing of the boiler. The boiler fan cycles though!

Personally I would not get rid of the time switch. Having the boiler on during the day when everyone is at work, or overnight when everyone is in bed is wasteful. As for the summer, I turn it off. Cool summer days don't normally require central heating, just put a jumper on.