Ideal Evomax External control wiring

[mark72]

Hi All
As part of an electrical install, I've been asked to wire a couple of commercial boilers in synchro. The boilers are Ideal Evomax and they have the shunt pumps below, and the external controls are 2 port valve for hot water, Central heating pump (But no 2 port valve on the heating), programmer, R/s and C/s.

So I'm intending to wire as an S plan and connect shunt pumps direct to boiler, but the part I can't understand is where the CH pump is connected.

can I externally power the pump through a contactor and switch the contactor from the boiler?

 

[tolly]

I may be wrong but, The CH pump wont wire back to the boilers, only the shunt pumps wired back to boilers. CH pump should only come on when CH is called for.

 

[mark72]

I thought that too but how do I wire the central heating pump into the s plan without getting a back feed through the HW circuit?

 

[SmokeyJ]

You need a motorised valve for that I'd say. Come off the live to the zone valve from the room stat to power pump?
I'm not too good with electrics so as far as stopping a backfeed I can't help...

 

[mark72]

I thought this also but the plumber insists he has done it before using another electrician

 

[ShaunCorbs]

how many pumps excluding the shunts

 

[mark72]

a shunt for ea. boiler (2). And the central heating pump

 

[ShaunCorbs]

a shunt for ea. boiler (2). And the central heating pump

a separate pump for hot water?

 

[mark72]

Sorry yes there is a pump on the hot water with the 2 port valve

 

[ShaunCorbs]

Sorry yes there is a pump on the hot water with the 2 port valve

the only way but not the best is wire the pump into the time clock (heating side) via a contactor

 

[SmokeyJ]

Fit a relay?? I don't really know how they work but I've see our sparks fit them on a few multi boiler jobs before...

 

[mark72]

But when you say not the best could the plumber have done something different because he seems to know his :nono:,and I'm not used to wiring commercial boilers. I asked why it didn't have a 2 port on the heating and he said I't isn't possible with with the pipework he has fit the boilers onto. What you suggest would work, but why isn't that the perfect answer to the problem?

 

[mark72]

someone mentioned a relay today, does anyone have more info on that idea? thanks for your last suggestion Smokey J.

 

[ShaunCorbs]

But when you say not the best could the plumber have done something different because he seems to know his ,and I'm not used to wiring commercial boilers. I asked why it didn't have a 2 port on the heating and he said I't isn't possible with with the pipework he has fit the boilers onto. What you suggest would work, but why isn't that the perfect answer to the problem?

as you would have passive heating with hot water

 

[mark72]

How much passive heating, would the pipes be as hot as the stat allows?

 

[ShaunCorbs]

How much passive heating, would the pipes be as hot as the stat allows?

what stat pipe stat or room stat?

 

[mark72]

Will I have a satisfied customer with switching contactor from heating call smokey J?

 

[mark72]

room stat.

 

[ShaunCorbs]

dont want to sound mean but sounds like plumber is trying to say money on not fitting parts and your inexperienced in wiring more than one boiler together

might be better posting it here as ask them to walk you through it

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[mark72]

Not mean at all I'm greatfull for your help!

 

[Dotty]

Pound to a pinch they're plumbed in incorrectly. They would need to be plumbed in to a low loss header. The shunts need to be running when the individual boilers do, and with an over run. Then you can worry about the heating and hot water circuits. How many heating circuits are there? How many modulated temps and how many constant? Is there frost protection? Weather compensation?

I would say you're looking at a bms system.

 

[mark72]

Hi All
As part of an electrical install, I've been asked to wire a couple of commercial boilers in synchro. The boilers are Ideal Evomax and they have the shunt pumps below, and the external controls are 2 port valve for hot water, Central heating pump (But no 2 port valve on the heating), programmer, R/s and C/s.

So I'm intending to wire as an S plan and connect shunt pumps direct to boiler, but the part I can't understand is where the CH pump is connected.

can I externally power the pump through a contactor and switch the contactor from the boiler?

 

[SmokeyJ]

As Croppie says the control for these types of install can be very complicated. The controls you have described do seem to be quite basic.
Put a Keston heat 45 in last week and noticed it had separate heating switch live and hot water switch live connections to boiler. I'm assuming Evomax is the same as basically the same boiler with a different flue. Wiring the switch lives to the separate connections to the boilers should prevent a back feed powering pump??
Boiler pump terminal to shunts
Timer to room stat, out of room stat and split to pump and to boiler CH switch live terminal
Timer to cylinder stat, out of stat to zone valve, and again split to pump and to HW switch live terminal
No need for relay or anything fancy? Makes sense to me but I'm no sparky
Give Ideal a call Monday, they would be the best to advise