BDR91 / Y87RF2024 - No permanent live feed

[Simon Shaw]

I want to install a BDR91 receiver unit where the old thermostat was and don't want to have to start trying to move the existing cables. It all works fine - but it would appear that the live feed is only on / live when the current Programmer is on - when the Programmer switches off there is no live supply to the BDR91.
Is this a problem or should the thermostat (a Y87RF2024) just re-connect to the BDR91 by itself when the live feed is restored (the Programmer next comes on) ?

The other option that springs to mind is to buy a RFG100 Mobile Access kit and leave the current Programmer switched on permanently (hence the BDR91 would have a permanent live feed) and use the RFG100 / App. to program the heating on / off times. Any thoughts on that as an option ?

 

[simond]

The second option would be best but better still is to locate the BDR where the wire to the current thermostat originates, rather than on the wall where the old thermostat was.

 

[endecotp]

Can't you fit the BDR91 next to the existing programmer or boiler, where you should have permanent live?

 

[Phill Peck]

Can't u move your htg on wire to live behind the programmer?

 

[Simon Shaw]

It's not that easy to trace the current wiring - the Programmer is next to the boiler downstairs, but there's also a 10-way junction box under the hot water cylinder upstairs - but all the wiring goes into the walls / under the floors, so it's hard to tell what is running where. The BDR also nicely covers the hole where the old thermostat was too - which also helps. The idea was this should have been a simple swap over !

 

[Steelmasons]

Receiver next to boiler/programmer or use the CM907.

 

[Phill Peck]

It's not that easy to trace the current wiring - the Programmer is next to the boiler downstairs, but there's also a 10-way junction box under the hot water cylinder upstairs - but all the wiring goes into the walls / under the floors, so it's hard to tell what is running where. The BDR also nicely covers the hole where the old thermostat was too - which also helps. The idea was this should have been a simple swap over !

Sorry I'm not with u. Regardless of route/changing colour in a junction box/wiring centre the wire that leaves "htg on" goes to that thermostat if you move it behind the programmer to the live connection it will be "live" and your problem is solved.

I'm guessing this is a diy job and you're not a htg engineer?

 

[Dan Robinson]

The idea was this should have been a simple swap over !

It is.

 

[Simon Shaw]

I think I must be missing something here. The current wiring is mains to ST9400C Programmer to Stat. and from Stat to boiler as I can make it out. At the moment the Programmer must be on and the Stat calling for heat for the boiler to fire. If I swap the current stat. for a BDR91 but make the live feed permanent surely the boiler will fire whenever the Y87RF calls for heat - even overnight (which isn't what we want) ?

 

[Phill Peck]

NO
why would that happen.
As I have said you need to move one wire! The receiver acts as a switch.

To prove the point why not leave your thermostat in place and move your "htg on" to permanent live behind the timer.
Turn stat down
Does boiler fire?
Turn stat up
Does boiler fire?

 

[Simon Shaw]

Thanks I'll give it a go and see, but I was assuming both acted as switches - and at the moment both the programmer needed to be on and the stat to be calling for heat. By changing it as suggested I was thinking only the BDR91 would be acting as a switch, and therefore the boiler would fire whenever that called for heat (even during periods when the programmer is currently off).

 

[Steelmasons]

It's taken nearly a week to sort this out?

 

[Simon Shaw]

Yes - been away for a few days, and then tried to trace / figure out the current wiring as best I can.

 

[Phill Peck]

It's a programmable stat isn't it?

 

[stem]

It can be quite simple.

1) Put the BDR91 where the thermostat is now, and leave the programmer permanently set 'on' [or at the programmer terminals move the existing 'switched live' presently feeding the thermostat to a 'permanent live' connection, as per gasservice1986 sugestion. This is a simple move of one wire from one terminal to an adjacent one. If you tell us the make / model of the existing programmer we can tell you exactly what terminals they are] The BDR91 would then be permanently powered.

2) Get the mobile access kit from Honeywell which will allow you to use a smart phone to set the time and temperature of the Y87RF2024 for up-to 6 periods a day. Set it up so that during the night the temperature is 5 or 6 degrees lower than your normal daytime temperature and the heating won't come on.

Job done.

Alternatively, take it back and instead buy a wired programmable thermostat and swap it for the existing thermostat. Wireless thermostats alleviate the need for installing cables, but as your wiring is already there..... You would still have to provide the permanent live supply as per 1) above though.