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.

 

[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?

 

[DefyG]

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

Only one zone would work, what about the other 7 heating zones?

 

[Sparkie30]

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

Correct it wont work since he has 8 timers.

Didnt think that there.

 

[Sparkie30]

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?

That would work, just need to wire the hw seperate.

To save the banging of the relays i would go for 8 way heatmiser 230v.
Have browns of 2 ports wired with each zone of switched live on the wiring center and heating pump connects to wiring center.

That will work.

 

[davesparks]

That would work, just need to wire the hw seperate.

To save the banging of the relays i would go for 8 way heatmiser 230v.
Have browns of 2 ports wired with each zone of switched live on the wiring center and heating pump connects to wiring center.

That will work.

What banging of relays? The click won't be much louder than that of the relays in a heatmiser box.

Using relays one can simply be unplugged and swapped if it fails, the whole heatmiser box would have to be replaced, and a direct replacement may not be available.
Also you have the problem of the pump running before the valve opens, if the valve is slow or fails to open it could kill the pump too increasing the cost of repair.

 

[Sparkie30]

What banging of relays? The click won't be much louder than that of the relays in a heatmiser box.

Using relays one can simply be unplugged and swapped if it fails, the whole heatmiser box would have to be replaced, and a direct replacement may not be available.
Also you have the problem of the pump running before the valve opens, if the valve is slow or fails to open it could kill the pump too increasing the cost of repair.

It is few years ago since last time i used a contactor, we used schenider make. They were noisy. I know that much. Maybe new ones out.

Ive installed few of those never had to go back so far.

Thats why the plumber should install the bypass.

 

[davesparks]

It is few years ago since last time i used a contactor, we used schenider make. They were noisy. I know that much. Maybe new ones out.

Ive installed few of those never had to go back so far.

Thats why the plumber should install the bypass.

Well yes if you were to install contactors it would be a bit louder, but then nobody suggested contactors, I clearly said relay.

Why should a plumber install additional automatic bypass units to overcome someone's inability to wire the controls in a way which prevents the problem occurring to start with?

 

[Midwest]

I don't know why you two are arguing amongst yourselves, when the OP has been asked a couple of times what system has been plumbed in, and has not responded, even though he popped briefly at 0405hrs this morning. Just saying.

 

[Sparkie30]

Well yes if you were to install contactors it would be a bit louder, but then nobody suggested contactors, I clearly said relay.

Why should a plumber install additional automatic bypass units to overcome someone's inability to wire the controls in a way which prevents the problem occurring to start with?

You did never said you didnt, id still go wiring Center. Just my choice
If the plumber knows his stuff he should always install a autobypass and set to 2-3 bars. Nothing to do with wiring. Safety feature.

Good luck to op

 

[Pauly]

OK guys I've sorted it know, fitted a relay which opens via heating valves, permanent feed on one side and feed to pump on one terminal and switch live to boiler on another along with switch live from hot water valve. Just to clarify for some of you it's a system boiler with secondary cylinder pump and secondary heating pump, 8 htg zones-6 bedrooms controlled by remote stats, hallways and bathrooms control via single channel time clock and lounge - kitchen controls via twin channel time clock doing the hot water thanks for all the comments

 

[diditrain]

I am a bit interested in this thread as I have never done a one like this before. The OP says it is a system boiler, therefore am I right in thinking that the boiler has it`s own internal pump?
I presume that this internal pump will have some form of pump overrun, controlled via the boiler.
From what I have read there are also two external pumps. One for the heating circuit and one for the hot water circuit.
The boilers internal pump will run no matter what the demand is for, be it either heating or hot water.
When there is a demand for hot water, the external hot water pump operates and shuts off as soon as there is no longer a demand for hot water. When there is a heat demand, the same logic applies.
Is this the general operational characteristics for this type of set up?