General plumbing questions.

Old 02-14-21, 01:51 PM
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General plumbing questions.

1) If I have two 1 1/2 PVC tubes coming together at a T joint, where one tube comes in at the 'side' and the other at the 'long' end - how do they know that I want them to form one flow continuing out the opposite 'long' end ? Especially if there is _any_ difference in pressure. What prevent potential 'backflow' ?

2) I'm working on our pool heater boxes. Today we have 3 rows of 6 boxes. We have a spa. If I drain the spa of all its water and send the water to the boxes to refill the spa it takes 2 hours. If I drain the spa and bypass the boxes the spa will refill in less than 30 minutes. My first test is to create 6 lines of 3 boxes. I am going to separate the current rows where box 3 and 4 connect, send the hot water out at box 3 and then start a new cold line into what is today box 4. So the (3) boxes at 3 and 6 will be returning hot water. Those two tubes will come together at a T joint.

3) Today all the (6) boxes in a row are connected with 1/2 copper and have male/female connections to join them (I am not the original plumber). Where boxes 3 and 4 meet I am going to remove the current copper and was thinking of using a 1/2 sharkbite connector and a 15" flexible hot water hose to feed into the 1 1/2 return PVC. Looking at Amazon - those sharkbite connectors are not that much more expensive than a simple 1/2 male copper fitting. Is that possible ? All I would need do is de-solder the existing copper

Any thoughts/advice appreciated.
Old 02-14-21, 06:49 PM
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I think we need some more information about what you are doing and trying to accomplish.

1) In most plumbing systems, a bit of a pressure differential doesn't matter. For things like fountains, where the pressure does need to be identical, usually a valve is installed on each line so any pressure differential can be adjusted for. Even a slightly longer pipe, or pipe with a few extra fittings can end up with a pressure differential.

I don't quite understand the heater box issue. I'd imagine the heathers intentionally slow down the water flow so the water actually heats. Thus, connecting the incoming water line so it bypasses the heaters makes sense. It will fill faster, but of course heat at the same speed. You may need to include a backflow valve though. You wouldn't want the spa water going back into your potable water supply.

Others with more spa experience I'm sure will be around.

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