Expansion vessel query.

2pints

Moved into the current house about 6 months back and have been using the cupboard where the hot water tank is to dry the small luandry items like socks, today I noticed for the 1st time  a sticker on the grey EV had  "Non Potable" on it, now whilst i'm not a plumber or heating engineer i've had experience with these EV before (not fitting or anything but seen it being recharged) in my previous house. It's been a while but i'm sure that he said the red one is for heating/hotwater and the other one should white or blue and is potable which is drinking water.

The question is, does drinking water come via a "potable" EV and and will it make any difference if it is the wrong type of EV.

Thanks

Bendy_House

No idea.

But if you post a photo of this EV and what it's connected to, good chance we can tell you if it's on the 'system' or the 'DHW'. I'd suggest, tho', that neither of these would be considered 'potable', the former far less so than the latter.

I doubt you'd keel over from ingesting a slug of DHW during a shower, but it probably ain't a good idea in any case, so having a N-P EV on this is no biggie.

Hudsonbutler

No red one in my heating system, both are white 

bris

It just means not for drinking water, Its used for the heating system. It will not in anyway be connected to the water mains

tacpot12

Non-potable (RED) EVs should not be used on drinking water, but drinking water may not even require a EV. White EVs are typically found when the domestic hot water (the hot water that comes out of your taps) is fed from an sealed hot water cylinder. Such systems allow hot water to flow from the taps at near mains pressure, although a pressure releif valves is usually used to ensure that the cold mains pressure in the house is dropped to a level that the hot water cylinder and (White) EV can withstand. 

You need to follow the line from the EV to see whether it is connected to the heating system, most likely, or to your domestic hot water sypply. If it is the latter, this is not correct, and should be changed for a potable (White) EV. I think the issue is to do with oxygen and corrosion. A heating system should have very little disolved oxygen in in, or corrosion is minimal (especailly with the inhibitors that  are added to the system). The potable water supply is turning over constantly as water is drawn from the taps, so it always has quite a lot of oxygen disolved in it. A non-potable (Red) EV isn't built to withstand the corrosion that this promotes, although it will do so for a few years.