programmer

[GeckoGas-com]

I was under the impression that the MP3-22C was a spring return valve and the SDMV2304 was a unishare motor open/motor close valve...


If someone else can confirm this; you have bought the wrong valve and your system will now need rewiring.

 

[philsno1]

I was under the impression that the MP3-22C was a spring return valve and the SDMV2304 was a unishare motor open/motor close valve...


If someone else can confirm this; you have bought the wrong valve and your system will now need rewiring.

I've stripped the old valve down and it's definitely motorised.

 

[GeckoGas-com]

But I'm sure it was spring return - Ie; the motor opens the valve and a spring pulls it back to the closed position when the motor turns off.... Check for a spring in there if you still have it.

 

[Dan Robinson]

It would be... Some spring back to a rest position, others need power to a different cable to return.

If you have the wrong one then you will be getting allsorts of shennigans.

I don't know your old valve's set-up I'm afraid; but as Gecko wrote, your new valve is power on pwer off - not spring return.

 

[philsno1]

there's a spring in there, I did try to get another Tower valve but it seems they no longer exist. The are the same number of wires in the new valve as the old one though, identical colours too.
The guy who used to do my plumbing has retired, but told me it would be the motorised control valve from what was happening - that is the hot water only working when the central heating on.
Do you think there's any way I could re wire this to work, if it is the case that it's the wrong type of valve?

 

[Dan Robinson]

There will be a way, but with all due respect if it has taken theis long to get this far, I expect it will be a bit beyond your DIYing abilities

 

[philsno1]

Thanks for the help Dan.

I will more than likely tackle the wiring, if there's a way, or if anyone out there has any info, I am a qualified electrician, but no experience whatsoever with heating systems, hence my seeming to poke around in the dark with this problem.

 

[GeckoGas-com]

I definately agree with Dan on this one...

My advice is get in someone who is competant at wiring up heating systems - This is not a two minute job if the wiring was never completed in an organised fasion on the first install - Like most systems...

Or trot back to the heating shop and get yourself a 3-Port motorised valve such as a Honeywell 4073 or ACL Drayton MA1/679 and swap the Sunvic with one of them - Much better quality valves IMO; especially for the money and they are both spring returns

 

[GeckoGas-com]

^^^^^

Alteration to the above if you are a sparks... Time to crack out the wiring diagram and rewire your heating system.

 

[philsno1]

Thanks guys, appreciate your help and concerns, I have been on manufacturers website to check the valve out and it says the following:

SUNVIC MoMo valves are available as two-port or three-port in all popular sizes. Easy-to-install, MoMo valves can directly replace all other spring return valves and are compatible with standard Y and S plan type controls systems. They are ideal for all new-build, refurbishment and upgrade applications. Wiring colours are identical, and industry-standard body dimensions mean minimal, if any, pipe work changes. No changeover thermostats or special relays are required. A robust manual thumbwheel and valve position indicator helps simplify commissioning and system checking. Actuator replacement does not require system drain-down.

...reading that you would think that there need be no re wiring?

 

[GeckoGas-com]

They are a direct replacement as the body is the same size - But the wiring is different...


Some systems have an ancillary switch; some don't; so you'll need to work out if the old tower valve had an ancillary in it... I'm sure it did by the fact that you had enough wires to do a "perfect" match (Good old Sunvic - I am suprised their domestic sector is still going tbh).

Then you'll need to wire the valve up as per the instruction wiring diagram to use either the clock HW/Heating off feeds or those supplied via your room/cylinder stats.

Alternatively; you could use an SD2701 head as per the selection guide on that same site/page



1) What color wires did the tower have?
2) What color wires has the Sunvic got?
3) What wires are you currently connecting each one too?

 

[philsno1]

They are a direct replacement as the body is the same size - But the wiring is different...


Some systems have an ancillary switch; some don't; so you'll need to work out if the old tower valve had an ancillary in it... I'm sure it did by the fact that you had enough wires to do a "perfect" match (Good old Sunvic - I am suprised their domestic sector is still going tbh).

Then you'll need to wire the valve up as per the instruction wiring diagram to use either the clock HW/Heating off feeds or those supplied via your room/cylinder stats.

Alternatively; you could use an SD2701 head as per the selection guide on that same site/page



1) What color wires did the tower have?
2) What color wires has the Sunvic got?
3) What wires are you currently connecting each one too?

The connection box where the valve and pump motor etc are terminated is a real mess, it was installed by the gas board. I have connected exactly as the original tower valve, other than the earth, which doesn't exist on the sunvic.

The wires on both valves are identical - colours are white, blue, grey and orange, there was an additional wire on the original tower valve, but that was wired to the earth, whereas there's no earth lead on the sunvic.

 

[Dan Robinson]

They might be the same colour, but that does not mean they do the same thing.

 

[philsno1]

That's a very good point Dan!

 

[Dan Robinson]

Remember that bar the mains feed to the wiring centre and boiler, the rest of the colours mean naff all.

Hopefully there is a logic to them (i try and use the sme colour wires from timer through to the final switchin and links so that its easy to trace any faults, but that is only really helpful if you now I did it. I have seen some real abortions done by DIY, gas board, and professionals.

I have seen some severe head scratching from Plumbers and Sparks alike when it comes to a heating wiring centre. You should have seen my face when I had to re-wire a five zone heating system with a single wring centre for the first time...

Try and follow the Honeywell conventions if you can - I think sunvic have moved over to the style as well.