Vaillant NTC sensor with non Unistor cylinder

[dbell1968]

We're currently spec'ing a system for a large Victorian terrace refurb. Is it possible to use the VR10 NTC sensor Vaillant supply with the VR65 to bring ebus control to DHW with any unvented cylinder?

The Vaillant manual suggests only the Unistors are compatible but the price of these is a bit off putting. If we were to remove the cylinder stat from e.g. a Megaflo then could the NTC safely be installed in the pocket?

If so then are there any other issues to be aware of?

 

[Stingray13]

my tuppance worth.

No its not with all unvented equipment should be installed entirly to manufacturers specifications if they say it can't then guess what the answer is.

 

[simond]

You could use an ebus NTC with any unvented cylinder that uses a dry pocket and has room in it.

In order to conform with G3 you will need to keep the 2 port valve that came with your chosen cylinder and wire it in so that it springs shut with the original mechanical overheat and manual stats from the unvented cylinder.

Set the temperature on the manual stat very high and then you will be under the control of the Vaillant system.

I don't think your reasons for using a Megaflo are valid; uniSTORs are usually cheaper so why not use the proper one? I wouldn't bother with a Megaflo at all, they are overpriced and by no means well made.

 

[dbell1968]

OK thanks, looks like the Unistor is the one to go for then.

Interestingly, the VR65 manual states that only 1 of the NTC sensor or the mechanical stat. can be wired in at any one time, so not sure how it would've coped with the suggestion of keeping the mechanical stat as the overheat protection?