Non-Mains Water, vented system question

[chris03]

Evening all. A little advice if you can help me.
We have a little cottage fed from a private water supply (well/spring). I use a lift pump to feed a coffin tank in the loft. The coffin tank then gravity feeds the hot and cold water system plus a central heating header tank in the usual way.

We are rebuilding after a fire and re-using / extending the old water system. My question relates to the hot water vent pipe from the tank which is at first floor.

The coffin tank contains our clean and treated water supply. I'm not sure about the hot water vent pipe being returned to the tank. Are there any other options? I don't want to return any overflow to the cold water supply. Could I put a new external vent/discharge pipe in instead? I'm assuming it is only there for failures/emergency and won't actually create a flow?

Many thanks
Chris

 

[Dan Robinson]

Millions of houses across the country don't have a problem with vent being over the cold water cistern.

 

[Terry lambert]

It would normal to have this over you cold tank.

You are correct in that it is a safety pipe and there would only be flow under fault conditions

What are your reasons for wanting to move it?

Because water finds it's own level the vent pipe would need to be higher than the cold tank

 

[chris03]

Thats very kind of you Dan, but there are also millions of houses who have drinking water supplies direct from the mains, hence why the vent pipe is not a problem in normal layouts.

I understood that our tanked drinking water supply should be kept separate.

 

[chris03]

Terry, I have no reference point from the old system as much was removed in the damage post fire.

Thinking about the quality of the cold water supply. It would not be a problem to run this to a high point on an external wall.

 

[Terry lambert]

The systems that are fed direct from the mains have a pressure releif pipe, and is a different type of system with different design features.

 

[Terry lambert]

Terry, I have no reference point from the old system as much was removed in the damage post fire.

Thinking about the quality of the cold water supply. It would not be a problem to run this to a high point on an external wall.

The vent pipe would be full of water upto the height of the cold water level and would be liable to freeze. I should think doing this may affect the hot water performance as well.

This isn't really an option

 

[chris03]

Sorry, I should rephrase that. I can run the vent pipe internally towards the tank in the normal fashion. Instead of swan necking into the tank I felt it logical to keep the vent and drinking supply separate, hence take this out externally.

Not to worry.

 

[Dan Robinson]

Chris, the water in that vent pipe comes from the same tank that you are worrying about...

It just happens to have sat in the hot water cylinder for a few hours.

Unless you have another cold water cistern supplying a different system, I fail to see what you are protecting?

 

[Terry lambert]

The chances of it venting would be rare and under fault conditions.

Is this tank supplying your drinking water as well?

 

[chris03]

Yes, drinking and hot water - only supply. I acknowledge your comment Dan regarding the source of the water and am grateful for confirmation that the vent flow would only be under fault conditions.

Guess that's me into the worlds smallest loft space again!