header tank overflow pipe into cistern overflow?

[traineedrip]

replacing a cold water storage cistern and have found header tank o/f hangs above as an open pipe. should header over flow it would current freely pour into the cwsc, unless the lid was fitted then it would come through the ceiling!

Due to position its going to be tricky getting a new external route for the o/f so could i tap into the cwsc overflow? I cant see water contaminating as i can join the pipe below the cwsc, so it would be unlikely to back track.

So is this an absolute no no or ok but not ideal? Do the header and cwsc need their own independent overflows?

 

[Dannypipe]

I'll get my water regs book and take a look though I might get beaten to the punch!

Yup, as I summised. It's a no no. Section 5, R14.2 I won't bore you too much.

'Schedule 2 requires that any pipe carrying fluid that is not wholesome water must not be connected to a pipe carrying wholesome water unless a suitable backflow prevention devise is installed.'

Plus in section 16 - CW services - it states that each cistern should have its own warning pipes. So you wanna do it by the books, it's going to be harder. Isn't it always!!!

You could fit tundishes to create an air gap, but then there is more potential for disaster!

 

[traineedrip]

Thanks Danny. Always the way!

 

[easyt]

I'll get my water regs book and take a look though I might get beaten to the punch!

Yup, as I summised. It's a no no. Section 5, R14.2 I won't bore you too much.

'Schedule 2 requires that any pipe carrying fluid that is not wholesome water must not be connected to a pipe carrying wholesome water unless a suitable backflow prevention devise is installed.'

Plus in section 16 - CW services - it states that each cistern should have its own warning pipes. So you wanna do it by the books, it's going to be harder. Isn't it always!!!

You could fit tundishes to create an air gap, but then there is more potential for disaster!

I jnow it is different when it is for a customer. If it were in my home amd routing was a major problem then I would put a vertical tee in the overflow pipe at highest point by cistern and fit a 300mm length of verical 22mm pipe. Cap it and drill a series of small air admitance holes in the pipe near the cap. I would call this an effective anti-siphon device.