One Way Flapper valve on pump outlet

[Costas > DownUnder]

MY VS pump that I use is supplied with a nylon flapper style one-way/check valve which is designed to fit directly into the outlet.

The valve itself is not water tight as it is made from nylon, therefore it does has not have true 100% water sealing capability.

Just curious as to why the pump is supplied with one? Instructions don't really say anything about it.

It reduces the outlet diameter a tad and it does add some restriction to flow due to the reduction in diameter of the outlet when fitted. I have removed it in my case and I can actually see/measure a slight increase in flow in my system - so it does impact performance.

Initially I thought it does the same job as a typical check valve which may be fitted on the outlet in some circumstances but not exactly sure?

Pump without valve - You can clearly see the difference in the outlet diameters....

 

[zea3]

I'm sure the pump designer thought including a little check valve would be a good added feature, and its not a bad idea if done properly, but probably not effective enough to prevent loss of prime if the water is siphoning out into the skimmer. It would be better to track down the cause of the siphoning on an individual basis than assume it is a common enough problem that every pump needs it to prevent loss of prime.

 

[Jimrahbe]

cdu,

I am pretty sure it is there because you live "down under" and it prevents all the water from just draining out of your pool...

I agree 100% with taking it out, as you really don't need a check valve there unless you have some other issues..

I have got to say that is one nice looking pump.

Thanks for posting,

Jim R.

 

[Sminor]

That is a sweet looking pump! You sure that wasn’t just a safety cover during shipping? Just to keep something from falling in...

 

[PoolGate]

+1 I am thinking that was supposed to be removed upon installation.

 

[sktn77a]

I am pretty sure it is there because you live "down under" and it prevents all the water from just draining out of your pool...

:lol:

 

[Costas > DownUnder]

cdu,

I am pretty sure it is there because you live "down under" and it prevents all the water from just draining out of your pool...

I also emailed the manufacturer and they replied as follows:


The check valve is included for use if required.

- Install isolation valves before the pump section and after equipment, if the pump is below the water level of the pool.

- For pump installations 500mm above water level, it generally requires a foot valve at the pool or check valve in the suction line. Suction lines must be installed below water level until just in front of pump location and vertical riser used to reach pump inlet. AstralPool pumps are rated to a maximum head of 25 meters however refer to your pumps data plate for actual achievable pressure.



So it it looks like it is just a cheap version of a check valve.

While cheap, it adds a reasonable amount of unwanted restriction thereby affecting flow and it does not seal as well as a true check valve does.

Probably OK with 40mm PVC but with 50mm I would not recommend using the included check valve.

Much better to use a decent separate check valve which usually offer way less restriction.

I have got to say that is one nice looking pump.

One of the larger/common brands used DownUnder.

It uses a DC motor driven by an electronic speed controller to become a VS pump.

Seems to work quite well and is fairly quiet and efficient.

 

[Costas > DownUnder]

A few pics of it disassembled into its major components....


Electronic control module sub assembly - This simply sits on top of the motor housing and is affixed by 3 hex bolts and a weather proof/sealed plug & socket arrangement is used to connect to the actual motor windings.

Motor housing with rear fan and front plate attached:

Volute, diffuser and basket:

Impeller: