Spa Drain Line Airlocked

xford66

Member
Dec 17, 2019
9
Georgetown, TX
Hello,
Having an issue with Spa Return line, seems to be blocked.
I just drained about 80% of pool and 100% of spa, also used shop vac to clean out dirt build up under spa drain cover. After refilling pool and spa, then running pump for a while in pool mode (pulling water from pool drain and skimmers) everything looked to be working perfect, but when when I switched to Spa mode ( pulling water from spa drain) the pump basket went dry. I stopped the pump, removed cover and basket and no water is coming out like it usually does, note my pool/spa is about 8 feet higher than the pump due to elevation changes across property which causes water to pour out anytime pump cover is removed.
I filled pump/basket with water, reinstalled cover, started pump and same issue, goes dry.
Pretty sure I have air locked the return line from the spa, wanted to check if any tricks to fix this.
Thanks!
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,713
SW Indiana
I think you are using the wrong term. A return line takes water to the pool or spa from the pump. A drain or skimmer line allows water to flow from the pool or spa to the pump. Air won’t stop the flow. With an 8 ft elevation difference, you likely have a check valve before the pump. Good place to look for blockage.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
16,912
Bedford, TX
66,

I have never heard of an air lock on an in ground spa... :scratch:

My first thought is that one of your valve actuators is bad, but I can't make that work in my head...

When you switch between the pool mode and spa mode, do both of your automated Intake and Return valves move 180 degrees??

Post a couple of pics of your equipment pad so that we can see all of the valves.

Thanks,

Jim R.
 

xford66

Member
Dec 17, 2019
9
Georgetown, TX
Yes, doesn't change it, (I'm sure you know this) but that is on the pool side to choose main drain or skimmers, seeing normal water flow/pressure from pool in all 3 positions of the manual 3 way valve.
Only seeing issue when the electric valve actuator rotates 180 to pull water from spa, no 3 way valve on this side.


Yes prior to draining, pulled water from spa fine, no problems.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Duh. :hammer: Pay attention Pat. Since you see the actuator moving 180 degrees, we would assume everything is moving inside okay (for now). Have you tried pushing water backwards from the pump to the spa to see if water flows out okay? You'd have to switch to spa mode first of course. Since you mentioned dirt and such earlier, I wonder if there's partial blockage since this only just started happening. A garden hose inserted into the inlet side of the pump. Wrap a rag around it if you need to. @Jimrahbe, any other thoughts?
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
16,912
Bedford, TX
66,

When the system is working in the pool mode and you switch to the spa mode, does the pump immediately run out of water or does it take a while??

In my mind, I can't think of how the valves being out of position would cause the problem.. If the intake valve was stuck in the pool mode, when you switched to the spa mode water would still come in from the pool side???

If this were my pool, I would put a little water in the spa and then remove the Intake actuator, and then the Intake valve itself.. Since the spa is elevated, in theory, water should flow into the spa drain and pour out of the Intake valve.. If it does not, then the line has to be blocked.

Are your underground pipes solid or flexible? I have heard of flex pipe collapsing...

Thanks,

Jim R.
 

xford66

Member
Dec 17, 2019
9
Georgetown, TX
Yes, pump immediately runs out of water when switch to spa mode.

Valves don't look to be an issue to me either, water flow is normal when in pool mode but no water in spa mode, so really leaning toward some type of blockage in spa drain line.

Not sure on pipes, have not seen any flexible pipes and haven't seen underground pipes to know.

Thanks for the help everyone! thought this might be a common issue seen after draining pools/spas and wanted to see if pros had any tricks.

I'll recheck a few things like the spa drain, may run the hose down to see if any obvious blockages.
 
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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
16,003
Northern NJ
Yes, spa is full.
Yes, spills over like normal (in pool mode) due to valve on return line has about 25% going to spa.
note my pool/spa is about 8 feet higher than the pump due to elevation changes across property which causes water to pour out anytime pump cover is removed.
Then the return line has water flowing to the spa. The spa suction line should have water in it and should naturally flow down to the pump due to the spa being higher then the pump.

Everything points to you having a broken check valve in the spa suction line that is frozen shut. Or something fell into your spa suction line while it was empty and blocked it.

I can't see the details of your spa suction line to the pump in enough detail to see if there is a check valve there.