Filling loop or one way valve and gate valve

DublinDilbert · 26-07-2017 11:12PM #1

Hi all,

Is it ok to have a gate valve and a one way valve between the mains and a sealed heating system, with the gate valve closed (unless filling).

I know the theory behind a filling loop but I never see the loop physically disconnected in any system, so it's an isolation valve and a one way valve.

Thanks

jca · 26-07-2017 11:21PM

I wouldn't be a fan of gate valves tbh they never really shut completely. A lever type ball valve would be better. The last thing you need is heating water making its way into drinking water.

K.Flyer · 26-07-2017 11:48PM

Or.. you could just fit a filling loop and use it as it is meant to be used...

Better to have the filling loop, pressurise the system, disconnect and cap each end.

DublinDilbert · 27-07-2017 06:40AM

Thanks guys, it was an open system converted to a semi-sealed system, but as many do they kept the expansion tank in the attic.

I'll throw a filling loop on it, then there's no question of what it's for.

The expansion tank is sitting on 2 planks of wood above the main water tank with the over flow from one into the other like the one on here a few weeks back. Who does stuff like that

DGOBS · 27-07-2017 02:31PM

For main supply, single NRV would not be acceptable, minimum will need a double check valve (filling loops have double check valves built in), even at the has to be a temporary connection (hence the removable flexible hose and blanks that come with a filling loop)

This is prevent possible back flow into the mains system, which could contaminate the mains supply with bacteria and chemicals from your heating system, under water bylaws the gate valve and NRV would not be acceptable and you would be liable for any contamination you caused.

Filling loop or one way valve and gate valve

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