Combi Boiler System Help!

[ash_s3]

Hi all!

Im about to move into a house, it has a pretty new Worcester Bosch combi boiler installed but the control gear is pretty old and naff.

In the airing cupboard (where boiler is) is some kind of programmer which is fed via a SFS, i dont understand how to use it at all, all i know is it feeds the boiler via a 4G flex (all british gas branded stuff)
Its a mechanical one with the plastic tabs you push in when you want it on/off and its noisey as hell!

In the Kitchen there is a stat on the wall, its an old british gas own brand thing and part of it is missing! There is a 1.0mm T+E and 1.0mm Single core to it from the programmer.

i want to know if i need both controllers? what do they actually do?
id like to change them to digital ones, for both efficiency and looks, what do you recommend?

Thanks very much

 

[Deleted member 9648]

If it's a combi you only need a room stat wired back to the boiler...programmable would be a good idea...and the supply fused spur should be adjacent to the boiler.

 

[robsparky1975]

do you have a manual for the boiler? what is the single core cable?should not be a live i hope,programmable roomstat as previously quoted the best option,but the cables sound a bit worrying so maybe get rid and use a wireless programmable(reciever unit next to boiler) wprs to replace existing ,i take it the nearest rad has 2 lockshields.bgas stuff if just drayton/acl badged with their name.

 

[ash_s3]

Lockshields? what are they?!

The single core cable is run along side the twin (1980's sparks saving money on not buying 3core + earth!)
So at the current room stat i have a perm live, neutral and a switch wire back to programmer/boiler

So you can get a room stat with the 7day program functions built in?
Id like to set the boiler to come one at certain times like in the morning until say 8am on a weekday but till say 9/10am on a weekend.

hope this makes sense as im just getting confused with it all, never done any domestic heating wiring before.

thanks for the help

Ash

 

[offshorealex]

loads of programmable roomstats that will do that, honeywell or danfoss ones are pretty good looking too. They only need a common and switched live (assuming the boiler isnt zero volt switching, which i would doubt by the sounds of it) lockshields are just radiator valves which cant be thermostatically controlled. The radiator in the room the stat is in should be fitted with this to avoid two conflicting means of temperature control.
Alex

 

[leeweimaraner]

If it's a combi you only need a room stat wired back to the boiler...programmable would be a good idea...and the supply fused spur should be adjacent to the boiler.

shouldnt boilers plug into a socket now instead of a spur?so the plumber gets away from the part p of running a spur in??

 

[ash_s3]

Something like this? HONEYWELL CM907 PROGRAMMABLE ROOM STAT 7DAY (WIRED) (CMT907A1041) - Onplumb Ltd

 

[offshorealex]

Thats the one, the danfoss one is the tp5000 i think.

 

[Deleted member 9648]

shouldnt boilers plug into a socket now instead of a spur?so the plumber gets away from the part p of running a spur in??

News to me mate but the plumber shouldnt be doing the electrics anyway should he?

 

[robsparky1975]

i am working for a heating firm at the moment so have picked up all sorts of techniques on boiler systems as would not have had a clue before,if i were you i would get rid of existing roomstat cable it sounds a bit slap dash what they have done,you can get a wirelless programmable roomstat honeywell about the best around,5 core cable from boiler to reciever unit next to boiler l-n-e and say black to i think its rs(common) and white to rt(switched live return) this is 240v and when reciever gets signal from roomstat relay sends 240v to white core for switch live,take new 3 core flex from fcu into boiler for supply,think of the roomstat like a 1way lightwitch,use brown sleeving on black/white cores as you probably know already,good luck

 

[Guest123]

My advice......rip all the old kit out, and as the lads have said either find a compatible wireless programmable stat, or just wire in a new one.

As another option, you could probably buy the timeclock to fit in the front of the boiler if you wanted, and have a normal roomstat.

 

[ash_s3]

Thanks Rob, does the wireless receiver get its feed from the boiler or the FCU?
Which Honeywell do you recommend?


Re-wiring the stat is a bit of a no-no, as the house is almost finished now and dont want to be cutting up more chipboard flooring to get at the cables.

The current wiring is okay, its not ideal but its safe. As i said there is a PVC T+E and a PVC Single core (double insulation, not singles wiring)

Thanks

Ash

 

[UNG]

Personally I'd just use the Worcester controllers as they fit directly on to the boiler control main board.They do all the wireless stats,programmers and optimisers

 

[robsparky1975]

Thanks Rob, does the wireless receiver get its feed from the boiler or the FCU?
Which Honeywell do you recommend?


Re-wiring the stat is a bit of a no-no, as the house is almost finished now and dont want to be cutting up more chipboard flooring to get at the cables.

The current wiring is okay, its not ideal but its safe. As i said there is a PVC T+E and a PVC Single core (double insulation, not singles wiring)

Thanks

Ash

yeah 2 flexs into boiler 1 for power(3 core) the other for reciever unit(5 core) l-,n,e paired together into pcb control/mains in simples(like the ad),dont bother with worcester plug in job,trust me on this one ive wired up hundreds,canny go wrong with honeywell wprs cm907 i think about 80 quid maybe check plumb center or the like for stock,wiring diagrams in box if u get stuck,easy to use set up good quality product,the only gear i like to use now.

 

[ash_s3]

cant find WPRS CM907

can find the CM907, is the WPRS version just wireless?

cheers
ash

EDIT: is it the CM927?