Thursday, 1 Jun 2023
Is it a spa or a hot tub? Whatever you call it, ours has been getting worse over the years. It used to be switching the pool pump suction and return lines to the hot tub was all that was needed to get reasonably strong jets. Over time to get decent jet output I’d have to pump the water from the hot tub into the pool until the water level was below the jets. After waiting for all water to drain from the jets I could pump water from the pool back into the hot tub until it was full when I’d switch pump suction back to the hot tub. That was a minor pain, but it worked.
After getting the pool and hot tub re-plastered last year lowering the water level and re-filling wasn’t enough to get strong jets. The best guess is there is enough junk in the hot tub return lines to block the water/air flow. Today someone came out and removed the eyes to find the venturi tee nozzle – a plug with a 1/4” hole that threads into the venturi – has a larger hex diameter than expected.
Anyway, this is where things stand, today. Tomorrow the spa guy will be back to do more. I think he needed some tools he didn’t have with him.
Background
A few weeks ago (17 May) I took some video of what happens (or what doesn’t happen depending upon your point of view) when we try to use the hot tub.
A little bit of water and air from two of the five jets is all we get. When I lower the water level below the jets and then re-fill as described above things get a little better.
Almost looks good… except the flow is so week that sitting in front of a jet is enough to stop it from working. This is what we hope to fix.
Friday, 2 June 2023
The venturi tee nozzle screws into the venturi with is located about 12-15 inches in from the spa wall. They have a hex head so they can be easily installed-removed. Except… the very old units for my hot tub have a hex size that is nearly the diameter of the pipe between venturi and spa wall. Even a thin wall socket is too thick.
The repair guy got one nozzle out. I think he drove a large, long flat blade screwdriver into it to unscrew the nozzle. He’s going to order replacement nozzles. Current versions are smaller – and easier to install-remove yet will thread into the existing feed lines.
With that one nozzle removed I turned on the pump to fill the tub so I can put the cover over it for the weekend. There is plenty of pressure from the jet with the removed nozzle. It makes it quite obvious that the other nozzles are at least partially plugged.
Tuesday, 13 Jun 2023
The nozzles have been replaced. The old nozzles looked like they were made from 3/4” schedule 40 threaded pipe plugs with the holes drilled by hand. The holes were of different sizes and off center. The width across the flats of the plugs was about 1 3/16. The new plugs are smaller, roughly 1 1/8” across the flats. That extra space makes it much easier to access with a socket. A 29mm socket was used.
The hot tub was turned on after removing the old nozzled to clean out any junk that might have been blocking the water flow. The flow after installing the new nozzles is now pretty even. It used to be we had one strong stream and two that barely had any flow at all. That said, I wish the jets were stronger. I can boost the pump speed a couple of hundred RPM and will do that to see if it makes much of a difference.