Glow Worm 30ci

[ldoodle]

I have this boiler and have had it moved to the loft (it was under the kitchen worktop!). I want to install an RF room stat (Honeywell CMT927) and have just discovered the boiler is missing the 'MAINS VOLTAGE HEATING CONTROLS CONNECTION PLUG' (as labelled in the manual).

Buying the house 9 years after the boiler was installed, it's unlikely it's anywhere here. Installer problem took off with it having been told the previous owner didn't want a roomstat.

So I need one.

Any suggestions?

Thanks

 

[TCCHeating]

If you ring glowworm i'm sure they will send you one. Or you may be able to knock something up with a few connector blocks

 

[ldoodle]

It looks like the plug is needed as it slips on to a 3-pin terminal, rather than piggy-backing off a connector block.

View media item 69545
Also, am I reading the instructions right - only a live needed. Or is it simplified in the diagram such that both L and N required.

It translates to pin 3 on the connection plug going to a frost thermostat, pin 2 to a room stat and pin 1 nothing (DO NOT CONNECT).

View media item 69546

 

[TCCHeating]

Thats correct. Just needs 1 wire. a live return from the room stat reciever. You will need to get a permanent live and neutral to the rf reciever unit though

 

[ldoodle]

OK, thanks. Worth buying 1-core cable (if it exists) or just cut N and E off?

 

[TCCHeating]

Both are fine. Just make sure any spare wires are safely isolated

 

[ldoodle]

You will need to get a permanent live and neutral to the rf reciever unit though

Yeah I realised that. This one's a bit messy - some othershave a connector block for the main feed to the boiler, which you then piggy back off to the room stat... this one shows a junction box between the FCU and boiler.

Wouldn't want that in a visible location, like a kitchen! Could come straight out the FCU for both the boiler and room stat I suppose.

 

[TCCHeating]

Fcu? Do you mean the fused spur. I would take the perm live and neutral from the spur supplying the boiler if it's close. Otherwise you could take them direct from the boiler if you want.

 

[ldoodle]

Yeah fused spur. I think FCU (Fused Connection Unit) is the term now used though.

It's right next to the boiler... well about 20-30cm away.

I know what you're saying about taking them from the boiler, and that's how I've seen in some YouTube videos... this Glow Worm doesn't appear to be like them though as there's no connector blocks - everything seems to be a bigger version of PC internal connections in that it's all pin based.

I'll have a look and see if the cables to the pin connectors for the main supply are crimped or screwed or push on (with easy release). Although it might be easier to feed off the FCU anyway as I could site the RF receiver right above it, if it's greater than 30cm away.

Alternatively I could go from the FCU to the RF receiver, then piggy back of the RF receiver to the boiler. Or is that a no-no?

 

[ldoodle]

Or even have the RF receiver as a normal spur from a socket (I have a double socket next to the FCU for the boiler), bypassing the FCU?

That way if the fuse ever blew, the RF receiver wouldn't lose power... struggling to see the point of it still working if the boiler is off though

 

[TCCHeating]

Or even have the RF receiver as a normal spur from a socket (I have a double socket next to the FCU for the boiler), bypassing the FCU?

That way if the fuse ever blew, the RF receiver wouldn't lose power... struggling to see the point of it still working if the boiler is off though

Thats a big no! It must be on the same circuit as the boiler. ( scenario: engineer safely isolates boiler at spur to work on it, rf reciever sends live to boiler while the engineer is working, bang) Just take them from the fused spur supplying the boiler! As you said its very close so thats your best bet

 

[ldoodle]

Hmmm... wired in the receiver to the FCU and it all powers up OK. The connections inside the boiler are crimped so I couldn't piggy back off these.

But it's not working. When I flick between MAN and OFF on the stat I can see the receiver coming on and going off, but not the boiler.

One thing the stat instructions don't make clear is what L terminal to use on the supply side, and what terminal (A or B) to use to loop back to the boiler.

On the supply side, it shows the first L terminal as being fed from the FCU, and the second terminal looping through to the boiler. I didn't do it like this; both the boiler and the receiver are fed from the FCU. But the little image shows the cable as being connected to the second L terminal.

Then on the loop to the boiler, it shows terminal A going into T1 on the boiler and terminal B going into T2 on the boiler. The little image shows both A and B terminals being connected. I've tried both A and B going into terminal 2 on the boiler.

 

[TCCHeating]

Link the perm live to the live supply terminal on the rf reciever backplate. I think you need the link L to Terminal A in your case from your description.

 

[ldoodle]

Link the perm live to the live supply terminal on the rf reciever backplate. I think you need the link L to Terminal A in your case from your description.

I don't have anything in the second L terminal on the perm live, so that would be pointless? I cannot link L to A as there is a divider between them completely blocking off cable runs between the 2 sides. I can't even go out of the unit and back in because the little cable access holes are only big enough for 1 cable!

 

[TCCHeating]

Mate, with the greatest respect, follow my advice!!! To be honest I wouldn't have normally advised some one as far as I have you! But I quite like you for your perseverence so here goes.

Have another look and I am sure you will find a way to make that link