Floor returns - asking for advice

[hexabc]

My pool has 3 floor returns which I have kept closed since I bought the house 20 years ago. (And I suspect original owners did the same.) Each time I open the Jandy I am appalled by dirty water coming out of these returns and I quickly close it back. Should I bite the bullet, open the valve and let the water flow and clean the pipes? Or it’s OK to keep it always closed? I guess I’m a little afraid that a leak on those never used pipes might develop under pump pressure. Probably I’m a little paranoid...

Jerry

 

[kimkats]

If it ain't broken don't fix it..................is that how it goes? Sure seems good for this one. If you do want to "fix" it then I would push your FC up to SLAM level then open them up and get ready to do a SLAM to clear up what you added to the water.

 

[hexabc]

Here is a thing I don’t understand. When the Jandy is set to 100% sidewall (the normal position), the filter pressure is 10psi. I turned the valve into its middle position where 2 sidewall and 3 floor returns are open and the pressure on the filter dropped by 50%. When I set it to 100% floor, the pressure went to 80%. I understand the gauge measures pressure drop on the filter so it should be proportional to the flow rate.
Does it make any sense? Why the flow drops by 50% when the valve is in its middle position? I’m probably missing something here...

 

[kimkats]

Okay lets do the math:

-How many side returns do you have?
-How many floor returns?

I want to make sure that when you turned the valve to the floor returns water came out of all of them (nasty water but water).

 

[hexabc]

The pool has 2 side and 3 floor returns. After I turned the valve to the floor returns, I went into the pool and could feel some flow from the shallow return. I could see debris flowing from all of them for a couple of seconds. I kept the valve in 100% floor position for about 15 minutes. Couldn’t notice visually any effects of the flow from the deep end returns after debris were pushed out (I didn’t dive to detect the flow). Here is a picture of the pool. The most-left return is 8 feet deep.

 

[kimkats]

I am more concerned that it went UP when it was only the 3 floor returns. The going down makes sense since there is less restriction. Who knows how many elbows and such there are for each return so I don't think it would be proportional.

My thinking would be 3 should be lower pressure than just 2 and 5 lowest of all. BUT like I said above unless we know how they are all plumbed there is not telling what is what really.

Can you take the floor return covers off? I am wondering if you could pressure test each line to make sure there are not blockages.

Kim

 

[hexabc]

My understanding of what the filter pressure gauge actually measures was obviously wrong. It doesn’t measure the pressure drop on the filter but the inlet pressure (relative to atmospheric).

I think that explains what I observed:
1. side returns only open - 10 psi
2. Side and floor open - 5 psi
3. Floor only open - 8 psi

I’m rather positive there are no leaks in the floor return plumbing as I never noticed any abnormal water loss.

 

[hexabc]

My thinking would be 3 should be lower pressure than just 2 and 5 lowest of all. BUT like I said above unless we know how they are all plumbed there is not telling what is what really.
Kim

That plus the floor returns have covers which restrict the flow. The side returns do not have any fittings at the end (I should have requested eyeballs when the pool was resurfaced last year...)

 

[PoolguyinCT]

My understanding of what the filter pressure gauge actually measures was obviously wrong. It doesn’t measure the pressure drop on the filter but the inlet pressure (relative to atmospheric).

I think that explains what I observed:
1. side returns only open - 10 psi
2. Side and floor open - 5 psi
3. Floor only open - 8 psi

I’m rather positive there are no leaks in the floor return plumbing as I never noticed any abnormal water loss.

That’s sounds about right!