Relay for UH pump

[cornel]

Hiya all,
I have WB 4000 system. 2 twin channel Lyric T6's and 1 single channel T6. 1st dos zone 1 and hot water with a 2port valve each. 2nd zone 2 and a 2prot Vale. The 3rd T6 go's to UH pump no two port valve.

First 3 liven up Orange (from B on receiver box) and that go's to LR on the boiler.

The single channel, from B on receiver box has live to the UH Brown (live) as well as LR to the boiler.

What happens is, any of the others liven up LR also liven up the UH pump.

(There is no room at all to fit a two port valve)

So I'm looking for a relay that I can wire in line on live from B on receiver box to LR at boiler to stop back feed on to B.

I can't seam to find something of the shelf. I tried RS Comp and TLC...

Any advice on a specific unit and where to get it from?

Thanks a lot.

 

[Gasguru]

Have a look at Finder plug-in DIN rail mount relays...

[GALLERY=media, 84827]Untitled by Gasguru posted 1 Nov 2014 at 6:22 PM[/GALLERY]

 

[bernardgreen]

A smaller case for up to two Finder relays on the integral DIN rail

https://www.tlc-direct.co.uk/Products/BHCT2.html

Other makes are available

 

[cornel]

Thanks but they are to big.


Any advice on this from RS.

I'm not sure how to wire the switch live. As it looks like live only go's on A1....

 

[Gasguru]

That relay requires you to energise the coil by switching the Neutral...prob. not what you want.

 

[oldbutnotdead]

All you need is a 240v DPCO or DPNO relay. Like these https://smile.amazon.co.uk/gp/aw/d/B08DNDQYMR?psc=1&ref=ppx_pop_mob_b_asin_title
And some spade connectors. Or just solder direct to the relay. They'll fit in a standard single patress box

 

[cornel]

Thanks, Ill have a look at the one on AMZ.

A question back to the Yellow one I posted on top, I spoke to an electrician in TLC this afternoon and he sugested I might be able to reverse the Live and Neutral and would end up with the same outcome, ie switching the live instead of the neutral, any thoughts?

 

[oldbutnotdead]

That RS one will work. But not very well.
The live from the relevant controller goes to A1/1 and to the boiler.
Neutral goes to A2.
The live to the UH pump connects to 2.
Problem you will get is if one or more of the other heating zones comes on when the UFH is on it will latch that relay (so UFH will continue to run even though the controller is not calling for heat), relay will stay latched until all the other heating zones are satisfied.
This is a standard problem caused when you use the line energising the relay coil to power whatever the relay is switching. Problem is avoided by using a permanent live at the relay COM contact(s) and only using the coil line to energise the coil.