pump not priming

[skygremlin]

I'm having some flow issues, just started last weekend.. Our robotic cleaner took a dump on me so I put in our old Hayward suction cleaner, but it never took off. That's when I noticed the flow was low and the pump never finish priming. So I'm thinking maybe something was in the cleaner I didn't see and is not blocking somewhere.

Regardless if I have either the ingress or egress valves (with respect to the pump) set to pool or spa the pump never finishes priming. If I move my spider valves to backwash it seems to run normal -> prime -> drop RPM to normal running. So I'm thinking I have something stuck between my pump and salt cell. I pulled everything off tonight that I could think of, but still no luck. I removed salt cell to look at it, pulled apart and cleaned the filter, removed the cover to the spider valve and everything looks fine there.

I see some places where it looks like I can unscrew to separate the pipes by the heater. But I don't a pipe wrench (yet) and I can't spin it by hand. I tried putting in a hydro flush in tonight. but doesn't seem to have enough water coming out..

Below is how my equipment is set up.. This might be a standard, but I don't know

Normal Config -> Does not finish priming:
In from pool or spa Jandy valves -> to pump (VS Pentair whisper flow) -> filter (Hayward DE filter) -> to Hayward heater (Gas) -> Salt Cell -> to pool or spa Jandy valves

Finishes Priming and runs normal:
In from pool or spa Jandy valves -> in to pump (VS Pentair whisper flow) -> filter (Hayward DE filter) -> Backwash lines

I'm out of ideas to clear this out. I'm hoping there is something simple that I haven't thought yet. If not I might have to break down and call to have someone come in and blow out that section and fix this

thanx all

 

[Texas Splash]

I didn't see a reply yet. Are you still struggling with prime? Have you done anything else to this point? Normally with loss of prime, I might be inclined to focus on the suction side, but your pump seems to hold prime fine when in backwash mode. So that would push me more towards a flow restriction. You had some ideas, but have you taken the filter apart and inspected everything inside - especially the grids and manifold? Curious if there is a restriction in there as opposed to just after the filter.

In any case, stick close by, reply as much as needed to keep the thread visible, and others will chime-in to try and assist. Have a good evening.

 

[skygremlin]

Thanx had a guy over today and he did the exact same steps as I did, except he took apart a section of pipes between the heater and the salt cell.

Flow again: Ingress pool / spa jandy -> Pentair VS pump -> hayward DE Filter -> Hayward Heater -> Salt Cell -> Egress Pool / Spa Jandy.

Turns out there's a Check Valve (Like the one below, but painted all black) I had no idea what that was, but it looks like it's stuck / not opening all the way.. Is there a reason for the tube like looking check valve verses the ones you can replace with the plastic see thru tops? This is right after the Heater. Would hot water say for the hot tub require something more sturdy and that's why the tube looking one is there now?


There now that looks li
https://www.google.com/search?q=pool+check+valve&tbm=isch&tbs=rimg:CXuFQQgFourmIjiEHoPSq8YRcj4_13JIbwz1bKhZXRclLAxmZZfVq6yMjfUHb7vRtMCganAlhzG7f84RGpCXHVAXR9SoSCYQeg9KrxhFyEcV7wX7sSr55KhIJPj_1ckhvDPVsRAPZNSR2gvd4qEgkqFldFyUsDGRG76G9HRL-woyoSCZll9WrrIyN9Efp-XLJGr91DKhIJQdvu9G0wKBoRl424G6n8ahoqEgmcCWHMbt_1zhBEs0pCMUXFjQioSCUakJcdUBdH1EauCmSgUisCn&tbo=u&sa=X&ved=2ahUKEwiQiLm-s5fZAhWCMGMKHd0cA74Q9C96BAgAEB4&biw=1426&bih=752&dpr=1#imgrc=VjBv3NaoztEglM:

 

[CJadamec]

That is just a cheap check valve. It was used because it's cheap and available at Home Depot or any place that sells PVC plumbing.

It is recommended to have a check valve after the heater and before the SWG to prevent any accidental backflow of high chlorine concentrations into the heater. Using a proper jandy style pool check valve would be you best option.

 

[Jimrahbe]

sky,

The check valve is required when you have a 3" tab feeder, because with the pump off, the acid from the tablets can back-feed into the heater and reduce the pH and damage the heater core..

It is not needed between the heater and a SWCG, because as soon as the pump is off there is no more chlorine and nothing in the SWCG generates the acid that is in the tabs...

It can't hurt to have a check valve with a SWCG, it is just not needed.. I would only install a Jandy style check valve.. the cheap ones are "Penny Wise and Pound Foolish"..

Thanks,

Jim R.