One boiler, two y plans, two power supplies

[Blacktail]

Hi,

Have just deleted an epic explanation of my problem because by the time I reread it it made no sense to me. Instead will prepare for the barrage of "its simply you fool" by asking this question.

How do you wire two separate properties with their own separate power supplies running there own separate controllers two a single boiler?

Even with relays wont you be sharing the circuit (at the boiler) between each property? Have spent the day bent double in a tiny hole under the stairs and I think its stopped the blood to my brain.

 

[R G]

Very strange , what about the boiler wiring , ie feed to the boiler and also return pump over run , please supply info on boiler wiring requirements, also ais the hot water cylinder being shared

 

[Lee Marshall]

thats very weird. i suppose its just like a system with multiple heating circuits though. boiler isolation would be required from both supplies next to the boiler though or when maintenance time come round things could get messy if the sparky thinks he has turned everything off!

 

[snowhead]

Where is the boiler, in one of the properties or somewhere else?

Does each property have it's own pump within that property or is it single pump?

 

[R G]

The best way I can think of is to use a multi channel system with seperate zones, but the electrical supply would have to be common , ie from 1 property

 

[Blacktail]

Will try and answer as best I can. The boiler powers up from the call from the 3 port valve it has no other permanent power to it other than via the frost stat . I have rewired property 1, including now for the first time the two port over temp valve which had all wires terminated in a choc block and stuffed under the tank...you getting the picture. Also plumbed in an auto bypass valve. The boiler neutral is wired back/shared with the electrical circuits of property 1. The client has always had major problems with the set up. It is an open circuit to both properties with no check valves or bypass valves, trv's controlling the rads and massive parasitic heat bleed between properties I genuinely think one controller may have been accidently controlling the other property and vice versa for years. So in property 1 the switched live from the three port feeds to relay 1. This relay receives a permanent L & N from property one circuitry, with its shared N to the boiler remember.

Property two feeds a common neutral from its circuits and a switched live from its 3 port valve to the second relay, wired into the same pins as the permanent L/N of relay 1 and thats it!! The switched live of both the relays were linked.

Since my rewire, property two wont fire up the boiler but then i dont see how it ever could have.

So after much head scratching i came to the conclusion that unless all the programmers are running off the same circuit you cant actually run the boiler from two separate power supplies.......I think

No to cylinder question. Each property has its own tank and CH in a y plan configuration.

 

[Blacktail]

Just to make clear re relays

".....Property two feeds a common neutral from its circuits and a switched live from its 3 port valve to the second relay, wired into the same pins as the permanent L/N of relay 1 and thats it!!......"

I mean same configuration as relay 1, not actually into relay 1

Snowhead; External boiler and each y plan has its own pump

 

[itselectric]

How do they work out who pays for what on the gas /oil bill.

 

[R G]

The only way I can think of is multi zone , but with only 1 electrcal supply

 

[combilau]

Why not put the boiler feed on its own meter then they can split the costs?

 

[Sintra]

Done you a quick sketch to see if this would work for you. Either have boiler on seperate circuit from both Y plans or have it linked to the A1 & A2 terminals of ONE relay but still going through the contacts as shown.

 

[Blacktail]

The two properties are holiday lets so no problem with who pays what!

Sintra. That may be genius but i need to look at it a bit more.... had a bit of Friday vino since last post:8:. Dont think the boiler can go on its own circuit as its only power in comes from the call from the controller. Linking them, wont we then have the shared N issue?

 

[Sintra]

This is what I mean feed boiler from Y plan 1 and it is still electrically separated from Y plan 2 or vice versa.

 

[Silly Sausage]

Sintra, would it be better to switch the Neutrals as well?

 

[Sintra]

Sintra, would it be better to switch the Neutrals as well?

No reason why not as an 8 pin relay will have 2 sets of switching contacts. I have only shown 1 set of switching contacts as it is Friday night and there is alcohol to be consumed. :lol:

 

[Silly Sausage]

Exactly why I asked, I'm not going to attempt to work it out at this moment in time!

 

[Sintra]

Well i have just tried to lol to keep some fussy people happy :lol:

 

[itselectric]

Might have to watch out for 2 different phases in this one Sintra

 

[R G]

What I was thinking about was the pump over run return , I was asking what wiring goes to the boiler . It may have a permanent live , switched live for the boiler, neutral and a pump return for over run , if not then above is goodi

 

[Sintra]

That last one I posted wont work because if Y plan 1 is not calling for heat then the boiler won't fire even if Y plan 2 is.

So I think the boiler needs a dedicated supply like this switched through both relays.