connecting to two unvented tanks

[Andy Saunders]

Hi, I have just had two unvented tanks fitted to replace a small unvented tank. two tanks were used due to restricted access space.

The plumbers recommended that one tank feed the ensuite and one the main bathroom which gets the main use and utilise one hot water kit to control both tanks. The installing electricians said this would not be possible and I would need an additional hot water kit which I duly purchased.

Each tank has its own two port control valve and the central heating has another.I guess that makes it S plan Plus.

Any ideas on the best way to connect to allow individual tank control from the evohome or will I be limited to using the evohome to control one tank only and use a separate tank stat and programmer for the other? I also have eight HR92 which are working ok with the new controller (ATC928)

Many thanks

Andy

[Richard]

Hi Andy,

1x evohome Controller can only have 1x evohome Hot Water Kit bound to it.

So yep either just control one of the cylinders (you could try one tank as a slave, but I cannot guarantee success here as they serve different areas so could be different temps) or get 2x evohome Controllers.

I hope that help.

Richard

[Andy Saunders]

Thanks

I will control one with the evohome and the other with a separate controller. Turns out the tanks were connected in series and feed all the house. This would work for us with independent control as we wouldn't always be trying to heat 300l of water. We all have a PV system that utilises the immersion heater so we can link that in to top things up. Honeywell suggested another evohome controller just for the hot water on the 2nd tank which seems a bit of an expensive way of doing things. Otherwise really happy with the way its controlling the CH.