Faulty Circulator Pump? Wiring Issues

[Scottish1]

Hi

In a new property and the boiler is not firing.

Investigating the junction box, there is a disconnected wire
-labelled Unknown Red in image
This cable runs from the boiler to the junction box.

My interpretation is that this is likely to be circulating pump neutral?

Any advice would be appreciated!

Thanks

 

[Avo Mk8]

I'm having difficulty correlating your table with the numbered terminals/functions in the connection box shown at the top of the diagram (presumably inside the boiler?)
Are you able to clarify exactly which wire(s) connect to terminals 1 and 2?
And confirm terminals 1 and 2 are not linked?
Or do you not have access to this? I think to diagnose this you need to be certain exactly which wire is what, and you probably need someone gas qualified to go inside the boiler

PS a red wire shouldn't be a neutral, and I don't think that is what it is - could be wrong?

as things stand, the boiler doesn't seem to have a neutral, a switched live, or a permanent live!

 

[Avo Mk8]

Hi. Just to clarify - when you say 'new property' do you mean new to you, or a new build?
The red and black wiring implies the original installation was done at least 15 years ago, so hopefully not new build!
Is this a new boiler install?

 

[Scottish1]

Hi Avo

Yes, old house but new to me ~1990's build.
Boiler is a Glow Worm Ultracom 30hxi installed~2008.

That is my challenge, the numbered wiring diagram is from the boilers instruction manual, however, I cannot get into the boiler to confirm the terminals :-(. So I dont know if 1 and 2 are linked.
I was hoping a bright spark on here like yourself might be possible to back-calculate the wiring?

Interestingly when I request the heating on with the controller I can hear the 3-way valve operate but the circulating pump does not start and nor does the boiler fire.

Thanks for your help!

 

[Avo Mk8]

Hi Avo

Yes, old house but new to me ~1990's build.
Boiler is a Glow Worm Ultracom 30hxi installed~2008.

That is my challenge, the numbered wiring diagram is from the boilers instruction manual, however, I cannot get into the boiler to confirm the terminals :-(. So I dont know if 1 and 2 are linked.
I was hoping a bright spark on here like yourself might be possible to back-calculate the wiring?

Interestingly when I request the heating on with the controller I can hear the 3-way valve operate but the circulating pump does not start and nor does the boiler fire.

Thanks for your help!

The boiler is responsible for powering the pump. So no surprise the pump doesn't do anything if the boiler doesn't have a live feed.
If the ONLY cable to the boiler is that with the red, yel, blu, earth, conductors, one might deduce that has to be the mains feed. You seem to have established the yellow is connected to pump L, so that leaves red, blu, earth. Should those be providing mains power to the boiler? If someone has already disconnected them, that may indicate there was a problem previously.
I'm not going to suggest you blindly reconnect those without first establishing it would be safe, or getting someone in to do that for you.
Best of luck resolving it.

 

[loz2754]

You'll need access to the boiler terminal board to see what goes where.

 

[Avo Mk8]

The manual for your boiler shows an electrical connection 'cartridge' accessible from underneath the boiler. Does this look like yours?
If so, with the boiler isolated, and assuming competence to investigate, it would be quite legitimate for you to unscrew the torx? screws that hold the cartridge up, pull it out, and open the cartridge to check which wire goes to which pin.
But only if you have the same version of interconnect as shown below.

https://www.wolseley.co.uk/wcsstore7.00.805.913/ExtendedSitesCatalogAssetStore/images/products/AssetPush/DTP_AssetPushHighRes/std.lang.all/ti/on/Glowworm_UltracomHXI_Installation.pdf

 

[Scottish1]

Thanks all, some progress.

I have continuity tested the electrical cartridge to identify what's what.
See highlighted in Red below what is the mystery cable.

I also confirmed Pump Live (Boiler Yellow) is correct.


Now knowing that Unknown Red is on the Live and highlighted in the diagram where should it be located?

Thanks!

 

[Avo Mk8]

If it's a Y plan system I think that red wire should go to the orange wire on the 3 port valve.
I'll get back to you later.

 

[snowhead]

Is this New to you property Owned by you or Rented?
If rented it's the Landlords responsibility to sort it.

If recently purchased by you, did the heating work when you looked around it?
Were you supplied with any paperwork for servicing, recent or otherwise, to show the heating was working without problems.

Was the boiler wiring table at the property or have you compiled that?
If that Red wire has been disconnected recently it's been done for a reason, and that needs finding before the wire is reconnected