replacing room thermostat

[JohnW2]

Further worrying development...Now even when my programmer is set for the heating to be constantly off and I have the old Satchwell TLX2259 re fitted, when it starts calling for heat, the boiler now fires up the heating even though it should not as I have effectively turned it off using the programmer ...Have I damaged the programmer or the boiler as well?

Unless I'm misunderstanding, something doesn't seem to add up here. I thought you said that with no thermostat at all (with the backplate of the new one wired, but the front part not plugged in), the boiler didn't fire up. If that is the case, I doubt that it is damage to the programmer or boiler that is making it come on when it shouldn't when you re-fit the old thermostat. Am I misunderstanding?

Kind Regards, John

 

[333rocky333]

 

[JohnW2]

.

 

[333rocky333]

 

[JohnW2]

deleted - a potentially confusing (to others) exchange between 333rocky333 has been removed

 

[blackdog1969]

Further worrying development...Now even when my programmer is set for the heating to be constantly off and I have the old Satchwell TLX2259 re fitted, when it starts calling for heat, the boiler now fires up the heating even though it should not as I have effectively turned it off using the programmer ...Have I damaged the programmer or the boiler as well?

Unless I'm misunderstanding, something doesn't seem to add up here. I thought you said that with no thermostat at all (with the backplate of the new one wired, but the front part not plugged in), the boiler didn't fire up. If that is the case, I doubt that it is damage to the programmer or boiler that is making it come on when it shouldn't when you re-fit the old thermostat. Am I misunderstanding?

Kind Regards, John

Hi John, On this set up with the new backplate fitted, the boiler will not fire with either the programmer set to on or off....And thanks for your continued feedback.
Regards Martin

Untitled

• blackdog1969
• 12 Jan 2015
• 1

 

[JohnW2]

Unless I'm misunderstanding, something doesn't seem to add up here. I thought you said that with no thermostat at all (with the backplate of the new one wired, but the front part not plugged in), the boiler didn't fire up. If that is the case, I doubt that it is damage to the programmer or boiler that is making it come on when it shouldn't when you re-fit the old thermostat. Am I misunderstanding

Hi John, On this set up with the new backplate fitted, the boiler will not fire with either the programmer set to on or off....And thanks for your continued feedback.

Thanks - that's what I thought. However, as was pointed out to me by 333rocky333 (in a potentially confusing exchange of messages, which has been mutually removed), contrary to what I wrote above, that does not necessarily prove anything much - in particular, contrary to what I wrote, it does not necessarily indicate that the programmer has not been damaged [if the programmer's relay/switch contacts had become welded closed, and if those contacts were in series with the stat contacts, then one would get the behaviour you observed].

Just to be sure, do I take it that when you refitted the old stat, when the programmer was set to 'off', the boiler only fired up when the stat was calling for heat (i.e. set to a high temperature) and not if the stat was not calling for heat (i.e. set to a low temp)??

Kind Regards, John

 

[blackdog1969]

Hello again, Short update....I managed to swing past B&Q today and pick up another thermostat which I have now wired up correctly (I think ).
The thermostat now calls for heat when it drops past the set temperature and switches the boiler on and off as required...However the boiler still fires even when the programmable timer is set to off as I reported before...I take it this now confirms that I have indeed damaged the programmable timer unit which will now need to be replaced
Best regards Martin

Untitled

• blackdog1969
• 12 Jan 2015
• 1

 

[JohnW2]

Hello again, Short update....I managed to swing past B&Q today and pick up another thermostat which I have now wired up correctly (I think ). ... The thermostat now calls for heat when it drops past the set temperature and switches the boiler on and off as required...However the boiler still fires even when the programmable timer is set to off as I reported before...I take it this now confirms that I have indeed damaged the programmable timer unit which will now need to be replaced

If switching the CH off with the programmer/timer doesn't stop the boiler coming on then I fear you are probably right.

Kind Regards, John

 

[eveares]

The thermostat now calls for heat when it drops past the set temperature and switches the boiler on and off as required...However the boiler still fires even when the programmable timer is set to off as I reported before

So the thermostat now works, but even when the heating is turned off on the programmer as if the programmer was turned on?

Am I correct??

Remember if you get a new programmer to get a 2 channel one.

I.e. This: http://www.tlc-direct.co.uk/Products/HOC27.html

 

[JohnW2]

Remember if you get a new programmer to get a 2 channel one.

I used to get a bit confused by this "N-channel" terminology they use, but I think I've cracked it! Do I take it that a "2-channel" programmer has one HW 'channel' and one CH one (which seems to be what the OP needs), so that a 3-channel one would have HW plus two CH zones ... and 1-channel would be CH only?

Kind Regards, John

 

[EFLImpudence]

Yes, likely.

Although, obviously the channels could be used for anything.

 

[JohnW2]

Yes, likely. Although, obviously the channels could be used for anything.

Indeed - although, in the case of, say, the '2-channel' ones, everything probably comes 'labelled' as CH and HW.

I think the potential confusion used to be (and maybe still is) that some were described as, say, '2-zone', which usually meant 2 CH zones plus HW, aka '3-channel'!

Kind Regards, John

 

[EFLImpudence]

Yes, likely. Although, obviously the channels could be used for anything.

Indeed - although, in the case of, say, the '2-channel' ones, everything probably comes 'labelled' as CH and HW.

You buy what you need.

I think the potential confusion used to be (and maybe still is) that some were described as, say, '2-zone', which usually meant 2 CH zones plus HW, aka '3-channel'!

Unless you have a combi without cylinder.

 

[JohnW2]

Yes, likely. Although, obviously the channels could be used for anything.

Indeed - although, in the case of, say, the '2-channel' ones, everything probably comes 'labelled' as CH and HW.

You buy what you need.

Indeed, but if what one 'needed' was a '2-channel' programmer for 2 CH zones but no HW, I'm not sure that one would necessarily be able to find one labelled as such.

I think the potential confusion used to be (and maybe still is) that some were described as, say, '2-zone', which usually meant 2 CH zones plus HW, aka '3-channel'!

Unless you have a combi without cylinder.

... and two CH zones, and a combi without its own (adequate) programmer. However, as above, I don't think I've ever seen a programmer which is labelled for 2 zones (and no HW), rather than CH and DW - but I admit that I've never had any reason to look for one!

Kind Regards, John