suitable new programmer?

[D_Hailsham]

Ch ON programmer contact goes to roomstat, switched live of roomstat goes to NC contact of a relay as well as CH pump.

HW ON programmer contact goes to HW stat. Switched live from this goes to HW pump and NO of said relay. Relay coil (240 volt) is connected to this point as well. Alternative if using 12 volt relay is to use opto isolator for mains isolation with LED side having suitable dropper resistor and diode. Again, details available

C of relay contact goes to boiler.

Doesn't that just give you either heating or hot water; you can't have both at the same time?

 

[suzieb]

Where would the frost stat come into the picture?

 

[DP]

Doesn't that just give you either heating or hot water; you can't have both at the same time?

DH, draw what I wrote and see for yourself. As a registered gas installer I have used this setp many times, though it is for gravity HW system. Circuit described is slight modification of gravity HW setup.

Where would the frost stat come into the picture?

I would be fitting a programable roomstat that will act as a frost stat as well. So now you will have killed two birds with a stone. AND you will be saveing fuel as boiler will be switching off during CH mode when house reaches desired temperature. Presently, boiler does not switch off, and the pump keeps running for the duration of CH demand. There would be very little or no disruption to make amendments to what you have at present.

Reading what you have and what you have purchased (FP715), complex control setup that I am sure can be simplified, seems you will need services of a heating engineer who can make sense of what has been fitted. Obviously, if you guys have installed the control system, then I am sure you will be able to recitify/ alter the system without any hassle.

 

[Whitespirit66]

Is this a G-Plan system, or is that something different? Never seen one.

If not G-Plan, what is it?

 

[DP]

Whitespirit, I thought G-Plan was a make of furniture. Indeed some fine crafted items of furniture.

 

[Whitespirit66]

Whitespirit, I thought G-Plan was a make of furniture. Indeed some fine crafted items of furniture.

I'm thinking more Satchwell G-Plan/SMC, than dodgy 70s sofas.

 

[suzieb]

Thanks everyone!

Have taken on-board all suggestions and comments and will see what we can work out.

 

[D_Hailsham]

Doesn't that just give you either heating or hot water; you can't have both at the same time?

DH, draw what I wrote and see for yourself. As a registered gas installer I have used this setp many times, though it is for gravity HW system.

OK then, here it is:

Untitled

• D_Hailsham
• 24 Jul 2011
• 1

Same question as before!

 

[Norcon]

Same question as before!

I don't think DP's drawing is the clearest but his description is correct and will allow hw and ch at the same time.
Follow his description and draw it out and it all becomes clear.

 

[picasso]

one way of doing it with a single relay, the g plan (I think) was motor on motor off valves) and some rather funky 70s flat pack furniture, it was akin to winning the lottery if you bought a bit with none of the pieces missing.

[/net] View media item 35949

 

[D_Hailsham]

I don't think DP's drawing is the clearest but his description is correct and will allow hw and ch at the same time.
Follow his description and draw it out and it all becomes clear.

The penny's just dropped.

I was concentrating on when the relay was energised for HW and forgetting that the CH pump could still work as it's before the relay. It's a bit like a Y-plan in that the HW Stat controls the boiler when both are on.