CH vent pipe

Hello,

A couple of years ago I converted our gravity-fed HW into a fully pumped CH system.I put all the pumps and valves in the airing cupboard after a tee in the vent pipe, such that there is always a clear run from the boiler to the top of the header tank.

I have been "encouraged" by SWMBO to relocate the pump and valves into the kitchen, to free up room in the airing cupboard and to reduce whirring noises in the night. This leaves me with a dilemma over what to do with the vent pipe.

The pipes that go upstairs would be one pipe for CH and one for HW but both of these would be "behind" a motorised valve. Is the easiest thing to add a new pipe that runs direct from the boiler flow to the header tank? Because it is designed to carry boiling water in an emergency, does it have to be copper all the way?

I'm not sure whether I could use my existing pipe work but with a valve such that it would short-circuit the pump and motorised valves and allow water to flow in an emergency (the vent is tee-ed off the HW cylinder pipes). Is this allowed? I'm thinking that the rules probably say it must be a completely open pipe with no valves all the way to the top of the header tank, just in case the valve fails?

Thanks, Stephen.

Reply to
Stephen
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If it is just the noise of the pump that you want rid of, then bridge the existing pipework for the pump and site the pump somewhere else on the CH loop. As long as you don't compromise any zone valves, then your system should continue working without problems.

Reply to
BigWallop

As you suggest, you could just have a separate overflow, but that may need to be 22mm.

You can have the valves and pump in the return. In that case you could provide a separate 15mm direct from the header tank to the return on the boiler (avoiding any valves and pumps).

Reply to
Michael Chare

Thank you, an interesting idea; I had not thought of that. Is their any performance advantage/disadvantage to having the pump and valves on the return "pulling" rather than "pushing" the water around?

Thanks, Stephen.

Reply to
Stephen

"Stephen" wrote

Make sure you look very carefully at the relative positions of the pump, vent and water make up connections. Certainly the vent and water make up need to be close to avoid either pump over or suck down. These both lead to fresh air being introduced to the system and all the headaches associated. Google "pump over" on this group and you should find chapter and verse from one of its most prolific contributors (the late Andy Hall) who was certainly an authority in such matters.

The other issue that may not have occurred to SWMBO is that relocation of the pump will probably lead to a cooler airing cupboard. Our system was much like the one you are considering and the airing cupboard was useless for clothes drying! Having moved the pump and valves in there its a useful part of the laundry circuit now.

HTH

Phil

Reply to
TheScullster

I've not found any disadvantage! The water is still being pushed, just frim a different point..

Reply to
Michael Chare

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