apologises mate forgot it was a combi , those wires are just a make and break circuit , on the circuit board theres normally a link when there’s no thermostat fitted , so when one is fitted the link is removed and it’s wire in and wire out, so indeed the 2 x wires is correct , need to make sure what the voltage is, some are 240 or voltage free

plus here’s a Honeywell wiring book

https://heatingcontrols.honeywellho...df/Heating-Controls-Wiring-Guide-Issue-18.pdf

hope that makes sense , this was the one I was thinking about, alas they’ve updated since I was fitting thermostats

https://www.ebay.co.uk/itm/17451455...7779&msclkid=74a675433be21165db0915a9834f4caa

or the T4 , can get it wired or wireless

hope that helps


Great minds think alike that is exactly the same stat as i was going to suggest last night but found Honeywell had up dated all there stuff:( thats why i was suggesting the t4 as being battery powered its just a make or break relay for the two wires.
And whilst doing this i checked my programmable stat and now the times are all to pot i cant change the time it gets to 10am then jumps to 0.00pm looks like i am going to be buying a new one ow but they have changed the design:mad:
 
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Great minds think alike that is exactly the same stat as i was going to suggest last night but found Honeywell had up dated all there stuff:( thats why i was suggesting the t4 as being battery powered its just a make or break relay for the two wires.
And whilst doing this i checked my programmable stat and now the times are all to pot i cant change the time it gets to 10am then jumps to 00.00pm looks like i am going to be buying a new one ow but they have changed the design:mad:

great minds , urs will be , mine was fried years ago, lol

plus ur right there with regards to the updates , blimey they have changed , see the CM927 is still around , that’s the one I’ve still got but wow £130 now

what is the model ur trying to change the times on plse , as sometimes u can reset them but of course depends what one u have

plus goes without question would never wish to try and teach u how to suck eggs mate as I know ur very knowledgeable

funny enough always found the wiring on some of the old vaillants a-bit confusing , think they got better but mainly fitted worcester , plus those old vaillants that had 4 x pcbs where fun to fault find

remember the old puma and the dry circuit board that failed, use to just resolder the joints where the live and neutral came in , that was unless the board wasn’t fried, lol, or those bloody wax stats

worked for keston boilers for a little while, biggest pile of junk ever
 
Yes for what you want the t4 will wire with just the two wires look for the heat only diagram / combi boiler