changed spring return valve for a momo valve

[DIYDarren]

Hi folks,

we have been having some trouble with our heating system for the last few months.Main things were the rads getting hot when we put on the HW. Thanks to google and the knowledge on here I diagnosed it to the old spring return ACL motorised valve. On checking both of the 2 port valves both had seized up solid I managed to free off one as it's like new for now however the I snapped the spindle of the CH valve. This was a 5 wire ACL spring return type.

I have now replaced it with a new (old) sunvic sm5201 4 wire MOMO type.The issues I am having with it are regarding the wiring. On looking at it and reading on the internet I beleive I will have to add another wire from the room stat as the old one returned under spring pressure and this one will need a feed to the other micro switch to close the valve so to speak.

We have a honeywell T40 room stat which is wired up as follows.

terminal 1 = Live
terminal 2 = Neutral
terminal 3 = Switched live to valve

How would I need to wire in the sunvic valve with regards to adding new wires etc.Should the T40 be earthed as currently it's not.. we had the house rewired a few years ago but on closer inspection the sparks chose not to rewire everything which included the room stat so it still has the old red/blk wiring.

I have checked the room stat and I get a +ve feed out of terminal 4 when the stat is closed /turned down.

Thanks for taking the time.Any help is greatly appreciated

Which wire off the sunvic fires the boiler? as it was the orange wire off my old ACL valve.

 

[matt1e]

I have checked the room stat and I get a +ve feed out of terminal 4 when the stat is closed /turned down.

terminal 4 connects the the valve white (white)
terminal 3 connects to the valve yellow (open)

Which wire off the sunvic fires the boiler? as it was the orange wire off my old ACL valve.

None of them i'm afraid it is the sm5203 that has that facility

Matt

 

[matt1e]

double post

 

[D_Hailsham]

You don't have to make any thermostat wiring changes. Just wire the momo valve exactly the same (orange to orange, etc) as the old valve.

The valve is opened by power from the thermostat onto the brown wire and closed by power from the grey wire. There is a relay inside the actuator to do the required switching.

 

[matt1e]

You don't have to make any thermostat wiring changes. Just wire the momo valve exactly the same (orange to orange, etc) as the old valve.


The valve is opened by power from the thermostat onto the brown wire and closed by power from the grey wire. There is a relay inside the actuator to do the required switching.

You are thinking of the newer sunvics

 

[DIYDarren]

terminal 4 connects the the valve white (white)
terminal 3 connects to the valve yellow (open)

I thought it was something along those lines after finding another switched feed off terminal 4 off the room stat . I thought this may be the feed that would power the other micro switch to to close the valve.

How would the boiler now get the signal to fire, as this was done through the switched live (orange) out of my old valve?

I dont have a relay in the actuator part, just the motor and 2 micro switches? The issue is, before I had 5 wires from my old spring return valve and one switched the boiler on, and now I only have 4 wires out of this momo valve

Matt what is the 5303 a room stat?



Thanks again

 

[matt1e]

Matt what is the 5303 a room stat?

no its the 5 wire version of the sm5201 (typo I meant 5203 and was too lazy to write sm i have corrected it)

the sunvic SM5203 has the extra orange wire

 

[D_Hailsham]

You are thinking of the newer sunvics

Didn't know there were older versions!

Incidentally, according to Sunvic's website the SM5201 is not momo!

Now I've found another page which says it is!!


No wonder most installers say that s*nv*c is cr*p!

 

[matt1e]

No wonder most installers say that s*nv*c is cr*p!

No argument here mate

 

[Dan Robinson]

Shlte valves, shlte website, phone line open VERY occasionally.

 

[D_Hailsham]

Wiring Diagram should help.

The SM5201 is not suitable!

 

[Boilerman2]

Do yourself a favour;
Start again BUT this time buy a Honeywell V4044C valve which is spring return, with auxilary switch (orange wire) type very reliable and will be easier to fit than what you are curently trying to do!!

 

[DIYDarren]

so this momo valve is only compatible with the TLX 2356 and 2910 room stats as on the diagram you posted? that doesn't make sense I thought you could have fitted it with most room stats.. Is there no other way around wiring this one in? or am I going to have to bite the bullet and swop it for another type that's suitable for my room stat and existing wiring?

 

[D_Hailsham]

so this momo valve is only compatible with the TLX 2356 and 2910 room stats as on the diagram you posted? that doesn't make sense I thought you could have fitted it with most room stats.

It's compatible with any stat which has a two-way switch; but that's not the problem. The valve does not contain any auxiliary switch to control the boiler; all you can do is open and close the valve.

Swap the valve for a Honeywell V4043 (The V4044 is a 3-port diverter valve).