Solar panel vacuum breaker sucks air

aflink · Jul 22, 2012

My ten year old vacuum breaker was sucking air. I thought it was defective and replaced with a new one just to see the new vacuum breaker behaving the same way.

See this clip I took on the roof: http://www.youtube.com/watch?v=JohILOpRv5U

Any ideas why this is happening?

Thanks,

-ari

JohnT · Jul 22, 2012

What is your pressure, and how is flow from the returns?

aflink · Jul 23, 2012

The pressure at filter is 30psi. see this video for return flow: http://www.youtube.com/watch?v=o4mQQzijDSo

JohnT · Jul 23, 2012

Although it's not unheard of, 30 psi sounds awfully high. It seems like your pump isn't able to push enough water unto the panels to close the vacuum breaker. Have you always run at 30psi? Anything else changed?

mas985 · Jul 23, 2012

When is the last time you cleaned your filter? A dirty filter will have high PSI, high PSI loss, low return flow and low pressure at the VRV so it won't stay closed.

aflink · Jul 25, 2012

Just to see how low the pressure could go I ran the pump without the filter cartridge in & water directed to solar panels. The pressure without cartridge in was 20psi. No bubbles in the return.

Then I hosed down the cartridge and put it back in. Now the pressure is back to 30psi, weak flow and bubbles in the return flow.

The pool is 15k gallon in-ground gunnite. The filter is five months old Hayward C17502 Star-Clear with 175-Square-Foot Cartridge Filter http://www.amazon.com/gp/product/B00198AXSG

Something wrong with the filter?

mas985 · Jul 25, 2012

The filter could be calcified. Normally, a properly operating cartridge should not raise the PSI by very much. Try soaking the cartridge over night in TSP and then after that, rinse and then soak in an acid solution (20:1). See the following link for more details on cleaning a cartridge filter:

how-to-clean-a-cartridge-filter-t4465.html

aflink · Jul 25, 2012

Thanks a lot, Mark, I'll clean the filter as you recommended. I'll post the result once it's done.