S Plan wiring using a Low Loss Header and a single System Boiler running 2 pumps

[doitmyself]

To be honest I assumed that 1 and 2 were actually not valid.live as honeywell don't refer to them in issue 16 of their book.

I assume you are referring to the diagram on page 5 of the Wiring Guide. The reason it does not show terminals 1 & 2 (HW OFF and CH OFF) is that they are not used in S Plans. The Y Plan diagram on page 9 does show terminal 1 as it is used.

The bottom line, as you suspected, is that I need to tell the OTC that the HW is not in demand so that it won't impact on the heating. The OTC kit from Ideal has it's own relay to isolate the device when HW is being produced, so if 2 on the programmer is a live feed then problem solved.

Do you mean Terminal 1, which is HW OFF? Terminal 2 is CH OFF.

I take it that you are not using the Ideal Kit. Why not?

It might be a good idea to read the Installation Manual to see how it works. It's not so simple as you appear to think.

 

[Elforleather]

Yes I did mean terminal one, sorry, mine was a typo.

I am using the Ideal unit, the one delivered to me was missing a relay and instructions, I called Ideal and they were unsure if the kit was designed for a a heat only or combi boiler and put in the wrong box, I think the box had been robbed at some point, I should have a new one tomorrow.

I'm sure all will become evident.

 

[doitmyself]

I am using the Ideal unit, the one delivered to me was missing a relay and instructions,

The combi kit and heat only/system kit are different part nos! The combi version does not include a relay as it is not needed.

Combi = 204914
Heat/System = 206152

 

[Elforleather]

It turned up today and all fitted and working now. I had the right part first time, but someone had liberated the relay from the box. I've fitted them I the combis before so knew the difference.

I had a free wire for the control centre so picked up the HW off at the programmer as you said, many thanks for that, I should have twigged myself.

My only struggle now is getting the customers to understand how it functions. I always find that's the toughest challenge. I did the Worcester FX controls course on Wednesday and sadly their latest range including compensator is as clunky as ever Worcester controls are with nothing very new or useful.

 

[doitmyself]

My only struggle now is getting the customers to understand how it functions. I always find that's the toughest challenge.

Particularly making them understand that the rads do not have to be boiling hot all the time.