Heating wiring advice

[Pauly]

I have wired a heating system with 8 heating control zone valves and 1 on water,all work ok,problem is it has heating pump which comes on with heating valves but also with hot water zone valve,how can I separate the heating pump to only come on with the 8 valves.

 

[bill01803]

relays

 

[davesparks]

You need to install a relay to seperate the heating pump, just make sure there can't be a situation where the boiler fires without a pump running

 

[Pauly]

I understand that mate but where do I feed the relay from bearing in mind there's 8 valves and I don't want to connect all together so if 1 valve opens it brings on all the others

 

[Midwest]

What 'valves' are they?

 

[Kamikaze]

I always thought you needed the hot water on for the heating to work. But to get hot water only one had to separate it from the heating?

 

[Corbs]

If there two ports valves you won’t need to add a relay as each port valve has a micro switch

So you have two pumps correct ? Else how is the hot water fed

 

[Kamikaze]

I always thought you needed the hot water on for the heating to work. But to get hot water only one had to separate it from the heating?

It’s alright, I’ve answered my own question.
Here is a wiring diagram for an S plan.

 

[Pauly]

Yes there are 2 pumps hot water pump comes on with switch live from cylinder stat and I've put heating pump on with the orange wire fed from the 8 zones but it also comes on with the hot water valve

 

[Midwest]

You wiring needs to be installed & connected in relation to the plumbing installation. What has the plumber told you to install?

It sounds like an S Plan would be suitable, but without know what the plumber has put it, we would be guessing.

 

[Corbs]

Yes there are 2 pumps hot water pump comes on with switch live from cylinder stat and I've put heating pump on with the orange wire fed from the 8 zones but it also comes on with the hot water valve

Both pumps connected to the boiler (switch live/ call) yif so boilers back feeding when the heating is on which is powering the hot water pump

Power the hot water pump from the port valve brown (call) and the cylinder stat needs to have the switch live from the port valve

Or install a relay/ contractor on the heating oranges and one on the call from the cylinder then wire every back from them like a standard s plan plus

TBH don’t know why the heating engy hasn’t just used pumps instead of port valves

 

[Wilko]

My head is spinning like that pump - I need a pic or a diagram to make sense o this'n.

 

[Devonchris]

It's just an S Plan + (Google it)

In your case it's S Plan ++++++++

 

[AJshep]

Yes there are 2 pumps hot water pump comes on with switch live from cylinder stat and I've put heating pump on with the orange wire fed from the 8 zones but it also comes on with the hot water valve

Yes as the orange wire is the output from the zone valve, and most likely connected to the switched live of the boiler then everytime the boiler fires up the heating pump will run.

Just put a relay in, this will probably work....
*Switch live of boiler in common.
*Oranges and of heating valve and heating pump in NC
* Orange of HW valve in NO
*Link NO of contactor to A1
* Neutral in A2

 

[Sparkie30]

Dont think you need a relay, just pair the pump doing the heating with the brown of the 2port valve doing heating.

 

[AJshep]

Dont think you need a relay, just pair the pump doing the heating with the brown of the 2port valve doing heating.

That would work as far as not back feeding or needing a relay, but I'd be a little bit cautious about wiring that way, I'm not a plumber but by feeding the input of the valve your operating the pump at the same time as the valve so for a short time you would be pumping against a closed valve ( maybe not a big deal) if a valve were to fail though I'm not sure that is too good for the system.

I know in commercial heating systems they install a loop of pipework (shunt loop) with a seperate pump which usally overruns to avoid this situation and to help dissipate the heat.

 

[Corbs]

That would work as far as not back feeding or needing a relay, but I'd be a little bit cautious about wiring that way, I'm not a plumber but by feeding the input of the valve your operating the pump at the same time as the valve so for a short time you would be pumping against a closed valve ( maybe not a big deal) if a valve were to fail though I'm not sure that is too good for the system.

I know in commercial heating systems they install a loop of pipework (shunt loop) with a seperate pump which usally overruns to avoid this situation and to help dissipate the heat.

Should have an auto bypass put on each 2 port for this reason

Why I listed both options in my post

 

[Wilko]

Hi - I haven't really understood what's going wrong from the original post - no diagram, what can I say ... but why not use the 2 port orange? At least the valve would be open when the pump is livened up.

 

[davesparks]

Dont think you need a relay, just pair the pump doing the heating with the brown of the 2port valve doing heating.

That won't work because you'd be joining all 8 heating zones together!

 

[davesparks]

I understand that mate but where do I feed the relay from bearing in mind there's 8 valves and I don't want to connect all together so if 1 valve opens it brings on all the others

Use an 8 pin relay.
Oranges from the 8 heating valves connect to A1
Neutral to A2
Permanent live to both commons
CH pump connected to one of the N/O contacts
Switched live to the boiler connected to the other N/O contact.

You could connect the pump directly to the oranges and just use the relay to operate the boiler switched live, but I personally would do it the way I have described above.

This of course assumes you don't need the CH pump connected to the pump terminal of the boiler fir pump overrun?