Dropping Water Level with Spa Running

[glkd]

The spa is adjacent to the pool. The controls allow to run either the pool or the spa (single pump). When in the "pool" mode, there is water going over the spillway between the spa and the pump. Wehn everything is off, the spa eventually ends up with the same water level as the pool. Until recently, when the spa was running, there was a small amount of water going over the spillway. Now, not only is there no spillway flow, but the level in the spa drops about 4".

There is a bypass line between the pool discharge and the spa discharge as shown in the attached photo. There is a one way check valve and a ball valve in this line. The left side is the pool side and the check valve arrow points towards the right (spa) side. The ball valve has always been open. The check valve was replaced about 8 years ago but I can't recall the symptoms that caused it to be replaced.

The filter pressure gauge shows about 7 1/2 psi with the pool pump running. It rises to about 10 psi when the valves are switched to spa mode. I tried shutting the ball valve when the valves were in pool mode and the pressure rose to 10 psi. The volume of water going over the spillway then decreased to a very small amount but appeared to keep flowing. Closing the valve in the spa mode didn't appear to change anything.

I replaced the seals and o-rings in the two Ortega motorized valves about a year ago after I found that the valve on the suction side was leaking air around the shaft and causing bubbles in the pool discharges. The new o-rings fixed that problem.

As there are no holes in the 3 way valve rotors, I don't see how the spa was ever receiving "extra" water so that is had a slight spillover. I also don't understand the purpose of the bypass line, the check valve or the ball valve.

Perhaps someone can enlighten me as to how the system is supposed to work and why it would suddenly change.

 

[mfk0213]

Hi GLKD,

I've had that happen to me before. The way the spillway works, basically, you only suck from the pool side, and return all (or mostly) to the spa. If the valve selecting the pool vs spa drain is leaking or stuck, this can lower your spa slowly. Same for the valve that selects pool or spa return. I'd check out those two valves and/or the actuators first. See if you can disengage the automatic actuators and manually set the valves. A failing valve actuator motor might not have enough 'juice' to move the valve all the way to the right position. Even a small leak in either f these valves will pretty quickly drain the spa. Check valve might be there for an air blower. Not 100% sure what the bypass line is there for, might be to lower the spa pressure, or for some down the line equipment that needs to lower pressure (sometimes some salt water chlorinators have flow limits, etc.). Just for reference, are you turning off your pump before running the valves?

-Mo.

 

[glkd]

Hi Mo,

Thanks for the quick reply. Unless I'm confused (entirely possible), I don't see how the spa could heat the way you describe the flow. In the spa mode, only the water from the spa is circulated through the heater, which has a temperature setting for pool or spa. If all the water was drawn from the pool, heated and then returned to the spa, I believe you would have to bring the whole pool volume up to spa temperature. With the system working the way it is now, only the spa water is heated and the pool temperature stays the same (other than a tiny rise from the spa spill over.

There doesn't seem to be a problem with the valves operating while the pump is running. They rotate very slowly and therefore don't cause any rapid flow change. I did check to be sure that both valves were rotating fully.

Also, there is no auxiliary equipment in the pool/spa circuit. There is a fountain pump, but its' operation is completely separate from the pool.

 

[mfk0213]

Hi GLKD,

There are two modes for operation:
1) Normal, suck from the pool, return to the spa. You wouldn't turn on your heater here, unless you want to heat the pool and spa, as you pointed out.
2) Spa heating, suck from the spa, return to the spa through the heater.

If either the drain or return valve is leaking, you can cross-communicate the spa and pool drain or return, leading to the effects you are seeing. Additionally, you might check to see if there's any excess water around your equipment. Heaters often leak - I have to fix mine every year or two, but the amount of water is pretty evident.

A line diagram of your equipment, showing where the plumbing was coming and going, placement of the valves, etc, would be helpful to troubleshooting.View attachment Pool Diagram.pdf

I've attached a sample diagram for your reference. I used MS Visio, but you can use anything.

-Mo.

 

[imrodee]

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[mfk0213]

Did you get it figured out?