Fluctuating Pressure - Suction Line Blockage? [VIDEO]

[bigdaddyyc]

First year owning a pool and have gone through the wringer getting this far. After fixing a seized motor, and using a drain king to ensure my pump primes, it worked and I could finally vacuum the pool. Then after a good day of cleaning and vacuuming, this happened on the following day:

Pool Issue - YouTube

As you can see from the video:

Filter Valve Setting: Waste
Pressure: Spikes between 0 to 15.

Filter Valve Setting: Filtration
Pressure: Somewhat consistent at 4-6 psi. Which is low. Should be 10-15 psi consistent.

There is always a small bubble of air in the pump when I turn it off. There seems to be air getting in either through a leak or perhaps an obstruction in the skimmer line from my vacuuming (maybe a rock?).

Pool's plumbing:
The main drain connects to the skimmer, which is a two-hole. The other hole goes directly to the pump's suction end. There are no lines as far as I know that connects the main drain directly to the pump.

The usual suspects have been checked:
-water level is good
-filter and pump gaskets have been checked and are doing fine.
-motor is running, no junk bogging down the impeller.

What I've done so far:
-Used a drain king to create pressure in the suction line and blow out whats there, didn't work. Tried at the pump and skimmer end.
-Used a shop vac to blow air through to try and clear it out.

Next up:
-reverse-plumbing the pump to push water through the suction lines.

Anyone know what the culript is? Perhaps you can save me some time re-plumbing my lines.

 

[zea3]

Exactly how high is the water level? What the video shows is what happens when the water level is too low. If you look in the skimmer and see a vortex of rapidly swirling water, almost the end phase of a toilet flush in appearance, the swirling water is sucking air into the plumbing system. The water level needs to be high enough that there is no vortex formed in the skimmer when the pump is on. The water should be 1/2 to 2/3 full in the skimmer opening.

 

[bigdaddyyc]

Exactly how high is the water level? What the video shows is what happens when the water level is too low. If you look in the skimmer and see a vortex of rapidly swirling water, almost the end phase of a toilet flush in appearance, the swirling water is sucking air into the plumbing system. The water level needs to be high enough that there is no vortex formed in the skimmer when the pump is on. The water should be 1/2 to 2/3 full in the skimmer opening.

The water level was good. I've now fixed the issue, for anyone looking for a fix with a similar issue, this is what I did:

- I cut out the suction line plumbing, as you can see form the video there are two 90 degree bends going into the suction line, which is not good. I found leaves when looking straight down the pipe, which were caught on a temperature sensor that goes into the pipe. I dislodged these leaves by going back and forth with a snake, and checking the blockage with a flashlight.
- I re-did the plumbing so that only two 45 degrees are used, and are farther back from the suction inlet to the pump. I used a union fitting to reconnect to the suction line, so that my pump can be easily removed in the future for maintenance/replacement without cutting out any plumbing. Union product for my pump: https://www.amazon.ca/Hayward-SP14953S-2-Inch-Socket-Female/dp/B0038ER6VG
- I used a hose to determine the location of any suction line air leaks. This video shows what I found to be the best method: Find an air leak in your swimming pool. - YouTube

 

[bigdaddyyc]

I think the issue was caused by a combination of a blockage and an air leak after the blockage in the suction line. The blocking material (leaves) are forced up to the sensor and created a blockage, spiking the pressure. Since the pump could not pull any water, it pulled a substantial amount of air in from a small leak up the suction line at a poly-pvc barbed adapter connection. The incoming air from the leak let the leaves settle a bit away from the sensor/blockage point, allowing the momentary passage of water, which again forces the leaves back up to the sensor to create the blockage again. The cycle repeats.