a total newbie, can you have a mix of 2 port motorised valves? a MOMO on one and

bmitie · Nov 3, 2011

Just found this great site, saved me a fortune!! Plumber was called to check heating problem, rads getting warm when HW on!! His solution, replace the drayton valve and actuator, drain system etc. I was not convinced so did a bit of reading, got to part, check spring on drayton, did that and... spring had broken loose!! re did it with a small screw, result, rads don't heat up anymore when HW is called for. After all my reading I now know I have a SUNVIC momo 2 port valve on the DHW and the DRAYTON spring return on the CH. And the sunvic model I have has a chequered history, szm 1801. To me it never worked properly eg switch off valve and boiler when hot tank reached required temperature, it may have always been faulty.

However, I digress, is it ok to have two different type of valves on an s plan system? I am still learning and checking what happens when I do various switching.

BMITIE

grimysparks80 · Nov 3, 2011

Re: a total newbie, can you have a mix of 2 port motorised valves? a MOMO on one a

As long as its wired up correctly the make of the valves doesnt matter

bmitie · Nov 3, 2011

Re: a total newbie, can you have a mix of 2 port motorised valves? a MOMO on one a

thank you for quick reply. As a follow up when I try to switch HW on first thing each morning using a boost facility on the programmer and if I have the wall thermostat, which is wireless for the CH at off the water valve will not open unless I switch on wireless stat! This opens the hw valve and the ch one but I then switch off the wireless stat and water stays on!! I did read somewhere that this is a normal reaction with the MOMO ie if wireless is set to off but its doing my head in! I still have to prove all the wiring.

bmitie

grimysparks80 · Nov 5, 2011

Re: a total newbie, can you have a mix of 2 port motorised valves? a MOMO on one a

If its been wired correctly the two should be totally independant of each other. do you have a 2 channel programmer?

bmitie · Nov 5, 2011

Re: a total newbie, can you have a mix of 2 port motorised valves? a MOMO on one a

yes, i have a 2 channel programer, i tend to leave the CH turned on in the programmer and then use the wireless drayton stat to control heating. The wireless stat is programmable as well and I can move it round as required. For hot water I use the boost function on the wall programmer viz on for an hour. I have looked at an s plan wiring diagram and the way I read it both should be independently controllable. I have it working after a fashion, if I press boost on water in the morning and it does not switch on I just turn on wireless stat and away it goes. Then when wireless goes off water stays on for the hour. I am going to wait until next year to have a good look at the wiring and as I live in a bungalow, with HOT press in one location, programmer in another, wireless stat in another and the boiler located in a purpose built house outside I have loads of exercise. And I dont want to muck up and lose the heat. The people doing the install appeared to know what they were doing but I have always doubted the wiring aspect and the method used is a bit higgedly piggledly but when I got it working as described I gave up.

Thanks for help and I'll be back no doubt.

bmitie

Kev the gas · Nov 7, 2011

Re: a total newbie, can you have a mix of 2 port motorised valves? a MOMO on one a

You should not mix motor open motor closed zone valves with motor open spring return valves.

Strange things happen.