Help please with a room thermostat.

TUVOK

Thank you for your reply.
I hope to be able to take the cover etc off the faulty stat this weekend, I will photo it then.
As regards a programmable stat, the friend does not need one as one person works from home and the other partner is quite ill and confined to the house.
If I can successfully change the mechanical existing faulty stat for a replacement one easily and at a very little cost, they will bve more than happy with the control that gives and the money saved on bills.

Jeepers_Creepers

Absolutely fair enough, TUVOK.

You might even be lucky and find that the old stat has a separate backplate with has the wires going to it, so literally all you'd need to do is unscrew one little holding screw on the front and lift the main unit right off . So possibly no wiring to do :-)

(That might be wishful thinking if it's 25 years old, tho'...)

If you post the photo - and also one of the actual stat model, please, we can guide you to a suitable replacement. Do you have a Screwfix or similar nearby your friend? 

TUVOK

Really appreciate your help.
I won't be able to get back and update etc plus photo until the weekend.
Yes, hopefully no prob getting front cover off, know it is a honeywell but no model number evident on front cover, perhaps when cover off might be a name etc of model/type.
If yes, should make it easier to obtain a new stat compatible with wiring etc, and yes a toolstation. B&Q and screwfix not too far.
Hope to have success as it's for my son who is confined to house with disability and his partner works from home to keep things going, so a reduction in heating through stat control would be a great help.
Thanks again.
 

Jeepers_Creepers

Cool, and you are welcome.

Take a photo of the old stat and stick it on here and I'm sure someone will be able to ID it. And hopefully point you towards the most suitable alternatives. 

TUVOK

Hello, here are a photo of the existing stat, it's a Honeywell and the model details are on the second photo.
 The stat must be well over 20 years old.
There is also some numbers on the casing, they are: 42006617

Hopefully one of you kind members may be able to help out with what replacement basic mechanical stat I should buy.
Many thanks.

Jeepers_Creepers

Hi TUVOK.

That's a Honeywell T6360B - the standard-bearer of analogue stats from that time :-)

Ok, your choice is.... any will do. Have a look here: https://www.screwfix.com/c/heating-plumbing/central-heating-controls/cat831042#category=cat4600002&sort_by=price

I'd look for one that says "3-wire installation" as this means you will use all the wires you currently have, so won't have to worry about safely terminating one behind your new stat.

From that list, I think I'd choose the Drayton RST2 https://www.screwfix.com/p/drayton-rts2-24002sx-manual-room-thermostat/1614r as it (a) has a nice LED to tell you when it's calling for heat, and (b) has a nice big dial.

If your friend would rather go for the Flomasta 111110151160 at £9.44, that's perfectly ok - it'll work just the same.

The existing Honeywell is hard-wired so doesn't have a removable backplate, so there will unfortunately be no unclipping of old, reclipping of new... You will need to TURN OFF THE POWER TO THE CH SYSTEM which should have a single switch somewhere near the boiler. Then you undo the wires going to this ol' stat and remove the actual unit from the wall - almost certainly two screws at the side.

The new stat WILL have a backplate which you screw to the wall - hopefully using the same old screw holes. The three wires (and the earth) will then be transferred to this backplate, and the new 'stat body clipped on - jobbie jobbed.

Your existing Honeywell has 3 wires and an earth. The 3 wires are:

Terminal 1 has RED wire = LIVE

Terminal 2 has BLACK wire = NEUTRAL

Terminal 3 has YELLOW wire = Switched Live (the wire that becomes 'live' when the 'stat calls for heat and tells the boiler to come on)

And then there's the EARTH.

The Drayton RST2 has:

'N' - you put the BLACK wire here

'L' - you put the RED wire here

'3' - you put the YELLOW wire here.

And the EARTH gets 'parked' on the terminal supplied (the new 'stat is plastic - double-insulated - so this terminal doesn't go anywhere!)

Other stats will be very similar if not identical. If you are confused, come back on here.

Here's a shaky vid of the RST2, but it might help: https://www.youtube.com/watch?v=lq-wl77Yghs

vic_sf49

Thank you for all the above info.

My thermostat seems to "stick", and needs turning up to max temp then back, to get it to click on, so I was going to replace it. 

Much research was needed, but it looks like you've covered everything I need. Fantastic. 

Bookmarked for future ref, as my Screwfix trip can wait until the new year. 

TUVOK

Jeepers_Creepers said:

Hi TUVOK.

That's a Honeywell T6360B - the standard-bearer of analogue stats from that time :-)

Ok, your choice is.... any will do. Have a look here: https://www.screwfix.com/c/heating-plumbing/central-heating-controls/cat831042#category=cat4600002&sort_by=price

I'd look for one that says "3-wire installation" as this means you will use all the wires you currently have, so won't have to worry about safely terminating one behind your new stat.

From that list, I think I'd choose the Drayton RST2 https://www.screwfix.com/p/drayton-rts2-24002sx-manual-room-thermostat/1614r as it (a) has a nice LED to tell you when it's calling for heat, and (b) has a nice big dial.

If your friend would rather go for the Flomasta 111110151160 at £9.44, that's perfectly ok - it'll work just the same.

The existing Honeywell is hard-wired so doesn't have a removable backplate, so there will unfortunately be no unclipping of old, reclipping of new... You will need to TURN OFF THE POWER TO THE CH SYSTEM which should have a single switch somewhere near the boiler. Then you undo the wires going to this ol' stat and remove the actual unit from the wall - almost certainly two screws at the side.

The new stat WILL have a backplate which you screw to the wall - hopefully using the same old screw holes. The three wires (and the earth) will then be transferred to this backplate, and the new 'stat body clipped on - jobbie jobbed.

Your existing Honeywell has 3 wires and an earth. The 3 wires are:

Terminal 1 has RED wire = LIVE

Terminal 2 has BLACK wire = NEUTRAL

Terminal 3 has YELLOW wire = Switched Live (the wire that becomes 'live' when the 'stat calls for heat and tells the boiler to come on)

And then there's the EARTH.

The Drayton RST2 has:

'N' - you put the BLACK wire here

'L' - you put the RED wire here

'3' - you put the YELLOW wire here.

And the EARTH gets 'parked' on the terminal supplied (the new 'stat is plastic - double-insulated - so this terminal doesn't go anywhere!)

Other stats will be very similar if not identical. If you are confused, come back on here.

Here's a shaky vid of the RST2, but it might help: https://www.youtube.com/watch?v=lq-wl77Yghs

That's absolutely great. 
You have made a fantastic reply to my query and with your kind details should make the job easy (I hope ;-)  )
I'll put a thread on when I have hopefully completed the change and all is working ok.

Thanks again.

Jeepers_Creepers

Do you have a means of testing for live wires? The whole CH caboodle should be isolated by a single switch, but you can't be too careful.

If we don't hear back, we'll fear the worst... :-)

TUVOK

If I turn of all power to the house via the consumer box, that should take care of all live wires?