Potterton Performa 28i

[rymacg]

I have a Potterton Performa 28i boiler and there was water coming from the valve in the expansion tank so I assumed the tank was u/s, the manual says it is necessary to remove the boiler to fit a new one so I fitted an external expansion tank and all seems to be fine but my question is that I notice there are two pipe connections on the expansion tank so are there three separate compartments in this model and is fitting a standard ext tank ok? Any info would be welcome.

 

[hertsboilers]

Ok for an external vessel.

 

[dilalio]

But check that PRV and discharge is not full of crap.

 

[rymacg]

Ok thanks for the swift replies, I have replaced the PRV as there was a discharge but I just wondered if the exp tank had three separate compartments considering the Performa 28i is supposed to supply instant hot water to the DHW system.

 

[hertsboilers]

No the internal EV still has two sections, one is air and another is water

 

[dilalio]

Primary circuit for the CH and DHW is the same.

 

[gas112]

instant vessels are different they store a quantity of hot water for instant delivery hence the 2 connections

 

[rymacg]

Thanks gas112 but as dilalio says the CH and DHW primary circuits must mix in the exp vessel, is that correct?

 

[AGAS]

Thanks gas112 but as dilalio says the CH and DHW primary circuits must mix in the exp vessel, is that correct?

Where does he say that why would you mix ch water with dhw before you drink it

 

[rymacg]

l'm a little confused here, if therè are two water connections and one is CH and the other is DHW as the manual says, there must be three compartments in the exp vessel, I need a drink ha ha Merry Xmas.

 

[hertsboilers]

l'm a little confused here, if therè are two water connections and one is CH and the other is DHW as the manual says, there must be three compartments in the exp vessel, I need a drink ha ha Merry Xmas.

You are worrying too much. As I said at the beginning, an external expansion vessel is okay.

 

[rymacg]

Not worried so much as curious, CH working great no leaks and no loss of pressure, appreciate everybody's help.

 

[hertsboilers]

l'm a little confused here, if therè are two water connections and one is CH and the other is DHW as the manual says, there must be three compartments in the exp vessel, I need a drink ha ha Merry Xmas.

Yes, two connections to the expansion vessel, on Performa 24i and 28i, also Baxi Instant. One connection is flowing in, and another is flowing out.

 

[rymacg]

So the exp vessel in the 28i holds and heats water for DHW system, that being the case there is no exp tank for the CH.

 

[Phill Peck]

So the exp vessel in the 28i holds and heats water for DHW system, that being the case there is no exp tank for the CH.

The difference is that the water in the vessel is hot. When there’s a hot water demand the primary circuits is kept hot so there’s a lesser delay in hot water.
The water in the vessel is not the water that comes out of the taps.