Pump won't prime.

[Sandybits]

Hi all,
I had a call from a past customer who couldn't get his pump to prime. I installed a new pump about 2 months ago and after that he said he would take over the servicing. Pump is about 2.5 feet above water level

When I attended I:
Checked all valves open and sand filter on filter,
Removed vac plate from skimmer and checked weir door,
Checked pump lid and liubed oring,
Filled up pump with water, and restarted system but pump still didn't prime. Tried on recirculate without success.

Noticed water surged in pump after priming and restarting system then settled down below the inlet. Small bubbles appeared in bottom of basket. Also noticed air bubbles coming out of suction line whilst priming pump.

So I:
Used a drain genie (not sure what you guys call them but it goes on a garden hose and blows up like a balloon to clear drain blocks). This got blown out of the suction line on the pump side every time I used it. I also tried it from the skimmer side but was hard to ascertain if the water was making it to the pump. However the pump didn't overflow.

I concluded from air bubbles coming out of suction line while priming plus hose getting blown out that there was a blockage in the suction line.

I told this to the customer and his reply was that it was working perfectly before he opened pump lid to clean basket.

So now I'm doubting myself.

There is also 3 90s right before pump inlet that may be causing a problem. Skimmer basket is weighed down with rocks but has the basket with the hole which could at worst still allow leaves past. We had a very windy night about 3 days before the call.

I also thought that customer may have left the filter on backwash then opened the pump lid letting all the water to drain out of the filter. That added with being nearly 3 feet above water level and a 1.25hp pump and 3 90s before the pump may have added to the woes.

Any ideas appreciated.

 

[cfherrman]

Might be a good one for a air fitting in the pump basket drain, filter on closed, to try to blow out the suction line with a air compressor.

 

[PoolNewb2020]

One thing I know about customers, from automotive experience, is that a very small percentage will admit their fault. In majority of cases stuff always works perfectly before they touched it. So don't doubt yourself and diagnose the problem based on your experience, not what the customer says.

 

[Sandybits]

I caught up with the customer (who is the subject of this thread) and he said a leak detector came out and, by pressure testing the suction side plumbing, found an air leak in a loose non-return valve that was buried at the front of the pump inlet.

The problem was solved but left a question: How did this non return valve become loose?

Anyway thought I'd add the follow up for posterity.

 

[duraleigh]

Not sure what a non-return valve is and I am not sure what you mean by buried. You had a valve buried underground? Surely that is not what you mean.