Need help with vacuum breaker issue

[rhedayi]

Recently I repalced my 8 year old whisperflow 2hp pump with a hayward Ecostar. I am having issues with a vacuum breaker that is preventing proper flow.

Here is the setup.

Pool with elevated spa that spills into pool, and the equipment is about 15 feet higher than the pool, about 8 feet higher than spa.


on the lines to the pump, there is a Jandy check valve, it is functional, I dont lose prime.

on the return line, there is a vacuum breaker like the one in this video
http://www.youtube.com/watch?v=JohILOpRv5U


In fact it looks identical to that solar application, we have no solar panels, but its the same valve


Issue is this.....when the pump primes, the pressure is high enough the vacuum breaker is closed. When pump RPMs drop this valve opens as the total pressure in the system is about 4

If I dont close this manually with duct tape etc, air gets in and the return line gets air and the flow is interrupted. I have to assume that the hydrostatic pressure in the return line after priming actually helps the pump with the pumping (much like a hose draining a fountain using gravity only). The air disrupts this and pump has issues. My only remedy is to crank the VSP to 27000 rpms which causes enough pressure to close the valve.


I have been told if I remove the valve, the column of water may cause issues with siphoning from a weak point in the return piping. So, what can I do? is there a valve that is normally closed and opens with a small amount of pressure drop as when the pump turns off ?

 

[jblizzle]

I have never heard of the use of such a vacuum breaker like that and can not think why you would need it. There is nothing to siphon because both ends of the plumbing end in the same pool of water. I would think it is not needed, but am curious if others with more experience have different thoughts.

 

[JasonLion]

It is not at all common to put a vacuum relief valve in that location. I would remove the valve and seal the hole.

While that statement "may cause issues with siphoning from a weak point in the return piping" is technically true, there shouldn't be any "weak points" in the return piping. The plumbing should be completely sealed and remain sealed at substantial pressure/suction levels without any problems.

 

[rhedayi]

Purpose of vacuum break switch in pool w/o solar setup

Topics merged. Please keep everything relating to one topic/question/project together in one place. JasonLion

I have posted several questions on VSP selection, speed setting, etc. This is something that I am having difficulty determining and my pool pro who installed the pump suggested I bypass it altogether. I need a 2nd opinion.


Pool is 15k gallons or so, located approx. 12 feet below the pool equipment level

Spa is locate about 5 feet lower than pump equipment.

Setup was a whisperflo 2hp pump for the main pump. Jandy valves to have water circulate spa or pool or in spill mode. The pool return has the vacuum breaker switch for which I cant exactly figure the exact purpose. It is located in the upper left side of the picture.

When I swapped the WF pump to a Hayward 3400vsp, I quickly noticed that at any speed less than say 2800, the system was getting lots of air through the valve and the pump was losing its efficiency in flow rate. I then installed / rigged a spring on the valve so it stays closed a bit better. Still we have air in the system when running pump at 2000rpms. I simply capped the hole where valve threads and we are ok. So what is the purpose of the valve in this setup and can I simply toss it ? Thanks

 

[JasonLion]

The answers you got last month still apply. I didn't see anything new other than a nice photo, so I'm not sure why you are asking again.

 

[rhedayi]

I had actually forgotten I asked the exact same thing before. I did not post pics of the actual valve but I actually rigged up a spring to the bottom of the thing to try to keep it closed at low pressure etc. Seems it want to open with the low flow conditions. The pump loses efficiency. as an aside I actually have almost zero flow when pump is slowed to 1500 rpms so it seems 2000 is a sweet spot here. Thanks again

 

[Isaac-1]

I suspect that if you were to simply unscrew the Vacuum breaker valve while the pump is running on low you will find there is actual vacuum at that position, in other words pressure is so low that gravity draining will suck air in and water will not come out the hole if you were to remove the vacuum breaker valve. Again I am like the others, and see NO NEED for it with your equipment setup, I would remove it and screw in a cheap PVC plug with some teflon tape or pipe dope on the threads.

 

[rhedayi]

I suspect that if you were to simply unscrew the Vacuum breaker valve while the pump is running on low you will find there is actual vacuum at that position, in other words pressure is so low that gravity draining will suck air in and water will not come out the hole if you were to remove the vacuum breaker valve. Again I am like the others, and see NO NEED for it with your equipment setup, I would remove it and screw in a cheap PVC plug with some teflon tape or pipe dope on the threads.

Isacc
thanks for the reply, and yes there is vacuum in the line, I removed the valve and it basically sucked in a bunch of air. Somewhere between 2200 and 2800 the pressure changes form a vacuum to spill out of the hole.

I will just place a plug and call it a day.