Which non-return valves do I need to prevent my pool from loosing its prime?

[lockmc]

Hi guys!
This post is kind of a continuation from Clearing a blockage in the skimmer line

Basically, I blocked my pool because I didn't use a skimmer basket (new to this whole thing!).
I've pulled the concrete up and removed the blockage - there were some spring loaded non-return valves such as these (Holman 20mm In-Line Check Valve) that were blocked.

A pool guy told me to just remove them as they are not necessary and probably shouldn't have been under the concrete in the first place- so we did.
As you can see in the photo in the yellow box, we have just replaced it with straight pipe.

In the red box, you will see also a manual valve. That originally used to be a check-valve (one with the flap) but my pool guy replaced it with the handle driven one (can't remember why- i think it was meant to be temporary).

So, changes from original setup now are that we don't have the spring loaded in line non-return valve and the check-valve that goes into the filter pump is now a manual one.

The issue I have now is that both pumps don't stay primed.
So, obviously these parts are needed.

Does anyone know, if I was to just put a check valve in above the concrete (where it was originally), will that be enough to keep it primed, or do I actually need the spring loaded inline valves in the ground?

All of this is above water level.

I'm also curious why the solar pump never had a check valve on it

 

[ajw22]

In the US we use a flaper style Jandy check valve - https://www.jandy.com/en/products/valves/check They have an inspection window and can be opened up for repair.

See the installation instructions for the recommended positioning.

 

[Texas Splash]

Does anyone know, if I was to just put a check valve in above the concrete (where it was originally), will that be enough to keep it primed, or do I actually need the spring loaded inline valves in the ground?

Unless you have some other problem (i.e. suction side leak somewhere), the check valve should help. As I noted in post #47 of your original therad, it's all designed to hold water in that suction line and prevent it from emptying when the system is off. I suspect (hope) that's your only problem now, and that the lack or delay of prime is simply an excessivly long time the pump needs to pull water along the entire length of the suction line. The closer you place it to the pump the more suction line that will retain its water. Not an exact science perhaps, but they are generally not too far from the pump. Mine (My Pool link below) is about 18" away from te pump I suppose. Based on your photo, it may be a tight fit on that verticle riser pipe. If it doesn't fit, you may consider expanding what you have the work with above the conrete just to be sure and possbly include a union on each end for replacement later.

 

[duraleigh]

Your system is not airtight. You have leak(s) somewhere in your system or you would not lose prime. Sometimes, the easiest fix is to put in a check valve but it is a band-aid and not necessarily a complete cure.

I would suggest trying to find your leak first and, if that fails, then install a simple check valve on the suction side of your system.