Help needed to Identify part number for Sunvic three way val

[rieverjohn]

My daughters heating and hot water flow direction is controlled by what appears to be a Sunvic three way actuator marked <-DUOVAL-> on the cover. The nearest likeness I can find is marked <-DUOFLOW-> on the cover and the part number for this is SD2701.
Are the DUOVAL and DUOFLOW different and does anyone know the part number for the DUOVAL?
I believe these two actuators are spring return rather than MO MO.
On the system in question the DUOVAL connects to a J2802 relay junction box, it all appears to work but it is an unorthodox method of wiring according to Sunvic literature.

 

[kevplumb]

http://www.sunvic.co.uk/motorised_valves.htm

might help

 

[rieverjohn]

Thanks for your reply Kev, I have searched every reference I can find to Sunvic products without success, forums are my only hope.

 

[twgas]

I don't think there is a direct replacement for the old DUOVAL. It has to have the relay but none of the new ones, that I know of, use it. A rewire is the best option, I could be wrong, it has been known.

 

[rieverjohn]

Thanks Mick,
more to think about.
As I think I understand about the operation of the system, a signal to fire up the boiler and pump is fed to the boiler control board after the valve actuator has driven the valve to the correct position for the flow of hot water.
On my own system which has Honeywell valves this is usually a delay of a few seconds. But in my daughters system CH ON from the programmer pulls the relay on the relay control board and is also fed directly to the boiler control board through the RLY1 contacts and pin 5 of the relay board and starts up the boiler and pump immediately.
I assume this is not likely to cause problems but it makes it difficult to follow the logic of the relay board.

 

[twgas]

Does your daughter's system have a problem?
You ask if the way it's wired "will cause" probs, well, no it wont cause problems, but interfering with it might.

 

[rieverjohn]

Hello Mick,
daughter has complained that occasionally it doesn't fire up when it should. after a few weeks of complaints she decided it was usually on a Monday, the timing for Monday in the programmer was completely out, I set it up on Monday afternoon but she "thinks" it also happens at other times. I'm waiting for next Monday but trying to find out what parts are available if I need to look further. Can other actuators be fitted to the original valve body in place of the DUOVAL if that turns out to be a cause of any future problem.
I really don't want to change any plumbing.

 

[twgas]

There are other actuators that fit the body your D. has but as said they need a rewire - haven't seen a duoval for a good few years

 

[rieverjohn]

Thanks again Mick, one last question.
Which actuators could I use.

John