Hard Piping Make up water line to pressure side of filter system

[lovemyazpool]

There was another thread here the I read (from quite some time ago) about adding a makeup water line directly to the pool plumbing as opposed to using a hose. In my case, I have a hard line already plumbed from the house to the pool for filling, it was installed with the pool and there is a pressure vacuum breaker to prevent backflow from the pool to the city water supply the same as is required for our irrigation system.

The problem is that it is leaking and now is the time to make some changes as I am working on a Raspberry Pi/Arduino pool system of sorts which will include monitoring the pool level and adding water via a sprinkler valve when necessary.

In my case the easiest way would be to plumb the makeup line directly into the main return line of the pool. My question is would I need to install a backflow device on the filter side of my connection to prevent water that I am adding from pushing backwards into my filter system? My Pi will be monitoring my pump and will prevent the sprinkler valve from operating while the pump is in use, but when everything is off and I want to add water, I am worried (maybe without reason) that water from my makeup line (standard house pressure of about 65psi) will actually force water backwards through my system.

Any input would be greatly appreciated.

 

[pooldv]

It seems unlikely but possible. You could put a check valve behind it like this, Hayward PVC Check Valve 2 PSCV2S2DGR | Hayward PSCV2S2DGR

 

[gwegan]

This is one reason why PB don't do this. In theory there should not be a problem because the water will flow to the pool. However you may get reverse flow to the filter and you probably want a backflow preventor.

You should also check with your local building department. Some prohibit any connections to the pool plumbing from the water supply. Some require listed backflow devices ($200 at HD).

 

[lovemyazpool]

Thanks for the info. I will be using my sprinkler line to fill the pool and the sprinkler system is already up to code and uses a vacuum breaker per code to prevent reverse flow to the city water connection, so I am good there.

I was just concerned about connecting the makeup line to the return side and having water backflow into the filter system as I do not have any type of check valve in the system. It will be a pain to add one the way the system is setup, but if it is going to be a problem, then I will go ahead and add one!