Cabling needed for an unvented cylinder?

Joined
12 Dec 2018
Messages
7
Reaction score
0
Country
United Kingdom
Next year I am having an unvented cylinder installed in a cupboard that currently has no electricity supply. I have the ceiling below the cupboard opened up at the moment so it is a good opportunity to do run the cabling so that it doesn't have to be surface mounted when I have the cylinder installed. Could someone advise me on what cables I need to run to the cupboard, and which ones need to be on their own circuit? The cupboard will have the unvented cylinder, two zone valves (boiler is elsewhere in the house), and I guess the controls for the cylinder. Any guidance would be much appreciated!
 
You really, really should get an electrician to do this for you. You'll need an immersion feed.
Also a connection from the central heating wiring centre to provide over temp cut out and cylinder temp control (2C&E) and your plumber will provide a valve for the cylinder and that will require a cable to the wiring centre.

A lot will depend on the heating plan and the location of the boiler and the wiring centre. Best you get some advice on site. How its done is laid out in the Megaflo installation manual section 6.3 etc. Your cylinder may be a different make, but they all cable up the same.

https://www.heatraesadia.com/-/medi...n-manuals/megaflo-eco-installation-manual.pdf
 
cylinders over 170l seam to be coming with 2 immersions these days. So I guess 2 lots of 2.5mm cable to the CU would future proof ?
or maybe 2.5mm cable on a B25 MCB is sifficient. Don't know what they do.

2x 3 core and E for heating controls usually
 
Thank you both for that. I got it wrong re the zones valves - the system is going to be Y plan so just one 3 port valve in the cylinder cupboard as the house isn't very big. The boiler and wiring centre are on GF, the cylinder will be on the 2nd floor. I won't be doing any of the electrical work myself, just running the cables across the ceiling joists and up through the floor before plaster boarding the ceiling downstairs. I guess I should specify the cylinder now and check the number of immersions.
 
Look at figure 17 in the manual that I linked to. You will have two valves. The 3-port valve for the Y plan plus the 2 port valve that is needed for the cylinder.

You’ll probably only have/need one immersion.

It will be A LOT easier if the wiring centre were in the cupboard with the tank and the valves. Then you only need a single cable from the wiring centre to the boiler. Maybe another for the pump.. it depends on your boiler.
 
Back
Top