new MOMO valve, is it broken?

[gwinkless]

Hi

I need to replace the mid-position valve in my Honeywell Y-plan system. After reading up a bit I saw someone selling Sunvic drop-in replacement MOMO valves (SDMV2304) on ebay for a price close enough to the spring-return and I like the idea of MOMO and the manual dial so I decided to try it out and see.

Anyway, the valve arrived and before I fit it I tried turning the manual dial on the front; it will only turn in one direction and even in that direction it doesn't turn far enough to close the valve anyway.

Would you expect this or should I be able to turn the dial in both directions, closing the valve, while it's all disconnected?

For what it's worth the valve itself will turn (and close) freely in both directions if I take off the head.

I suppose I could fit it and find out - replacing the head is the easy part of the job so if the worst came to the worst I could replace that later - but I thought it might be worth checking here first

Cheers

Geoff

 

[mysteryman]

Your Y Plan wiring will need to be amended to suit the motor open motor close valve, which is what I think you mean. Only do this if you are sure of what you are doing. If in doubt, just put in a new Y Plan valve.

 

[gwinkless]

Your Y Plan wiring will need to be amended to suit the motor open motor close valve, which is what I think you mean. Only do this if you are sure of what you are doing. If in doubt, just put in a new Y Plan valve.

No it won't. The wiring is the same as for a 4073, unless Sunvic are lying. As you see here,

Untitled

• gwinkless
• 6 Mar 2011
• 1

(Apologies for the poor quality, I took a photo with my phone)

it's the same as the one shown in this post

 

[mickyg]

the wiring for a momo valve is NOT the same as for a spring return. A momo valve needs a heating off live , a spring return needs a hot water off live. Looking at that diagram it would suggest otherwise

 

[gwinkless]

the wiring for a momo valve is NOT the same as for a spring return. A momo valve needs a heating off live , a spring return needs a hot water off live. Looking at that diagram it would suggest otherwise

So are you saying the diagram I've posted (the one that comes in the box!) suggests that it is a drop-in replacement? I did research this before I bought it because I had no intention of making significant wiring changes to the system, and that is the claim they make.

 

[DP]

MOMO means valve needs voltage applied to it for it to open. To close, voltage needs to be applied (I think) to another wire to close the valve. These actuators only drive in one direction i.e. they are NOT spring return actuators.

Be advised some midposition valves do not return to home position when demand satisfied unless the power is turned off at the isolator.

 

[mickyg]

the diagram is the same as a spring return yes

 

[gwinkless]

the diagram is the same as a spring return yes

Great! So, having cleared that up, can we now get to the original question?

Do we think the manual wheel should fully close the valve in both directions when everything's disconnected? Or should I just connect it up and see if it works?!

 

[mickyg]

just connect it up and see if it works, if the wiring diagram is correct it will work. Manual positions on valves usually and deliberately put the valve into mid-position.

 

[twgas]

I dont understand how you managed to get a 3 port MOMO valve, 1 poer is always open on a 3 port valve, so by design the motor-on-motor-off is wrong. If you can explain otherwise I'd be more than willing to listen/learn.

 

[gwinkless]

I dont understand how you managed to get a 3 port MOMO valve, 1 poer is always open on a 3 port valve, so by design the motor-on-motor-off is wrong. If you can explain otherwise I'd be more than willing to listen/learn.

"Off" is really incorrect terminology; what it actually means is that it uses the motor to move the valve between all three positions. I guess it's used because people understand the MOMO term for normal valves.

The FAQ here is likely to be better reading than I can produce and is probably less prone to errors of understanding

 

[gwinkless]

just connect it up and see if it works, if the wiring diagram is correct it will work. Manual positions on valves usually and deliberately put the valve into mid-position.

Mmm; maybe I'd misunderstood and the manual override is only meant to enable you to return the valve to open.

Like I said before, if it's broken I can always replace just the actuator unit.

Thanks all for your posts.

 

[gwinkless]

Like I said before, if it's broken I can always replace just the actuator unit.

FWIW, the new valve went in fine - wired colour-for-colour against what was there before (apart from no earth) - and appears to be working perfectly.

 

[D_Hailsham]

the wiring for a momo valve is NOT the same as for a spring return.

Oh Yes, it is! Read the Patent

These diagram show the electronics of the 2-port (Fig 4) and 3-port (Fig 5)

M1 and M2 are the motor terminals, wire colours are standard.

View media item 33504