DIY Doctor

Main navigation

Drayton SCR Digistat and Nest e Heat Link

Postby PipsterC » Sun Jan 17, 2021 12:38 pm


I’ve tried to wire in my nest e heat link and remove my old Drayton SCR Digistat which controls my Gloworm Ultimate boiler.

The wiring currently has the Drayton with a live and neutral.
Port 1 according to Drayton is Common and Port 3 is Call.

The person who previously wired it in used an Earth lead to 3 but wrapped it in another tape to change the colour.

It has no Earth connected as it’s currently double insulated.

I wired 1 into C and 3 into NO and terminal capped off the live and neutral.

Switched it back on and the 3A fuse in the spur blew.

Any ideas why please? It appears to wired correctly but I don’t understand why this happened.

Many thanks in advance!
Rank: Labourer
Progress to next rank:
Posts: 1
Joined: Sun Jan 17, 2021 12:19 pm


Simply Build It

Postby ericmark » Sun Jan 24, 2021 2:29 pm

The instructions I can find for the Drayton has N/O and Com so you need to find out what 1 and 3 is, as you say seems wrong, fuse should not have blown.

You should have an earth even it class II just not used, 1966 the rules changed and earth has to be taken to any fixed appliance even it not used, only exception is ceiling rose to bulb holder.

The Gloworm Ultimate can use 24 volt 230 volt or a bus connection, and so can Nest e, as to if the bus on the Glowworm is Opentherm I don't know.
Rank: Project Manager
Posts: 2657
Joined: Fri Oct 02, 2009 8:49 pm
Location: Llanfair Caereinion, Mid Wales.

Display posts from previous
Sort by
Order by

  • DIY How to Project Guides
  • DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!

  • Related Topics