Weird Water Flow to Spa

[Michael1]

I can't figure this out. I have a pool with an attached spa. The water coming over the spillway varies considerably day to day.

From the pump, water branches off to the pool and spa. The spa side has a check valve, so if you have the distribution valve set to spa, it won't backflush into the pool line. I

I thought the check valve might not be opening all the time. I took it apart, and it works perfectly.

If I turn the distribution valve to "spa only", and then turn the valve back to "pool and spa" the amount of water increases barely a trickle to a nice waterfall over the spillway. It will remain that way until the next day, even if I turn the pump off and then back on.

Part of the problem is, I don't understand what happens to the water after it leaves the distribution valve and goes to the spa. I have six jets around the spa. I don't feel any water coming out of those, but maybe there is, just not much.

In the middle of the six jets, is something that appears to be a "blowoff valve". That does have some water coming out of it, but it doesn't seem like enough to account for all the water coming over the spillway when it is flowing properly. Hard to tell.

Then there is a drain on the bottom, and another on the side of the spa.

If anyone can explain spa plumbing (when attached to pool system) to me, it would be greatly appreciated.

 

[gwegan]

We need to see a picture of your equipment pad and a picture of the spa please.

 

[Michael1]

We need to see a picture of your equipment pad and a picture of the spa please.

Gwegan, thanks for getting back to me. I am out in the field for the next few days, but should be able to post after that.

 

[Michael1]

I finally figured out the mystery problem of no water flow to the spa, and thought I would report back in the event it may help someone else.

It turned out that when the DE filter got dirty, and the pressure in the filter increased, the resulting pressure drop across the filter meant that the water pressure to the spa was too low to get the water flowing into it, and out the waterfall.

I discovered this by accident one day. I thought I would give the filter a full cleaning, and took the filter grids out. I hosed them down. I then replaced them, and added DE accurately using a scale, so it had the proper amount for my Pentair filter. After I did this, lo and behold, water began flowing out of the spa again.

Since that time, I have noticed that if I have a pressure rise of about 5 psi from a clean filter pressure, the spa flows no water. At a 3 psi rise, it is still flowing but you can see it is reduced slightly. At 4 psi, it is about half the normal amount.

Backflushing only seems to partially clean the filters for me, so as a normal routine now, when the pressure gets to 3-4 psi rise, I take the filter apart, and hose down the grids. It takes a little extra time, but it does get the filter pressure down more, so you have to clean the filter less often.

I hope this helps someone else here.

Michael