Fitting Thermostat / Timer on Worcester 350 combi

[spamonion]

I've got an old worcester 350 combi boiler fitted in the garage, but with no internal room thermostat.
I've taken a look and seems to be simple enough to fit - from the installation manual just connect to terminal block 4.
for the thermostat I've been looking at some wireless honewell ones, but seems to be almost the same price to get one with a timer too, something like the CM927.

So here's the question - can i set the boiler to be "always on", connect the thermostat / timer to the room thermostat point, and let that control the schedule, or will that do some damage somewhere ? Should I leave the facia programmer connected, or should it be disabled in some way ?

thanks for your help
sam

 

[D_Hailsham]

I've taken a look and seems to be simple enough to fit - from the installation manual just connect to terminal block 4.

You use the two end terminals, which will be linked together as you have no stat. Remove the link!

something like the CM927

Probably the best around.

Can i set the boiler to be "always on", connect the thermostat / timer to the room thermostat point, and let that control the schedule

You will have to leave the existing timer in place. Just set it to always on for CH, it won't do any harm. (HW can still be timed if you want it)

The supply to the thermostat receiver should be on continuously. You could take it from the Mains connections at the boiler. You should use a heat resistant 4-core (plus earth) cable between the receiver and the boiler.

 

[spamonion]

Thanks very much for the quick reply.

The only thing about the worcester instructions is the third neutral connection from the thermostat - here's a snip from the manual

Untitled

• spamonion
• 21 Sep 2010
• 2

Can I ignore this if i'm using the CM927 and connect the L + N supply, then A and B terminals to the two end terminals ?

cheers
sam

 

[D_Hailsham]

Can I ignore this if i'm using the CM927 and connect the L + N supply, then A and B terminals to the two end terminals ?

Yes, ignore the neutral connection shown in the diagram. It was required for the old mechanical thermostats.

 

[satman44]

hi all iam looking for the instructions manual on a worcester 350 boiler where to fit a wireless thermasat control i need a wiring diagram to find the main block where to wire from iam looking to fit this onehttp://www.ebay.co.uk/itm/DIGITA...arden_Hearing_Cooling_Air&hash=item418f9a37d5 many thanks satman44

 

[satman44]

any help please

 

[EFLImpudence]

Try here:
http://www.freeboilermanuals.com/worcester_bosch_1.htm

I can't get the 350 to open.

 

[satman44]

same here wont open thanks

 

[satman44]

http://library.plumbase.co.uk/flipbooks/RE/wor350rsf_23136_t/wor350rsf_23136_t.html#p=13
am i right in thinking the wiring block is x4 thanks

 

[EFLImpudence]

Yes, see fig.7 on previous page.

 

[satman44]

http://library.plumbase.co.uk/flipbooks/RE/wor350rsf_23136_t/wor350rsf_23136_t.html#p=13
i take it its 2 wires to mains and 2 wires to x4 block where link is on boiler from the recever thanks
http://pdf-cdn.plumb-bay.com/salus-rt500rf-wireless-room-stat-manual.pdf

 

[EFLImpudence]

That would be best.

Supply L, N &E to receiver (park E if not required) and
Com & NO to X4.

 

[satman44]

sorry park E if not required not sure what you mean thanks
dont use earth if not required got it thanks

 

[satman44]

View media item 90366is this correct remone link and fit n/o and com which is which on the x4 block
is com last termanal thanks

 

[EFLImpudence]

View media item 90366is this correct remove link

Yes. Looks like it.
Your pic is too blurred but it should say Room Stat next to it.

and fit n/o and com which is which on the x4 block
is com last termanal thanks

From Fig.7 the terminal nearest the edge of the board will be the Switched Live (to NO) and the one next to it Live (to Com) -
but the way you are wiring the thermostat it doesn't really matter which is which as the thermostat just connects them.