No change in pump pressure after cleaning Hayward cartridge filters

[pwa2003]

First time cleaning our Hayward cartridge filters today. Pool is basically a new build (we only used it for 2 days last Fall before having it closed for the winter, and it has only been opened about 6 weeks thus far this season).

I've been keeping my eye on the filter pressure gauge. I assume the service that opened the pool set the green & red arrows properly (green at 9 and red at 19). As the black indicator got to about 17-18 PSI at 100% pump speed (3450 rpm), I figured it was time to clean. I know 6 weeks seems like a really short period for needing cleaning, but our yard has been torn up with lots of open trenches (ugh, the dust & dirt!), there are lots of trees in neighbors' yards, and we have lots of small bugs, grass clippings and some crazy winds from time to time. The cartridges were indeed filthy. I know they'll never be like brand new again, but I'm confident I did a thorough cleaning.

I was expecting to see a drop in the pressure after reinstalling everything. Weirdly -- to me at least -- the pressure is exactly where it was before cleaning. What do y'all make of this?

BTW, I only put the pump to 100% to check the pressure. The only other time it's at 100% is when it's in Spa Mode and we're heating/using the spa.

 

[1poolman1]

Never assume that a pool service knows about, or even looks at, the adjustable green and red arrows, most don't.
Large capacity filters, like yours, along with a VSP, don't always act like we would expect. Even if the pressure gets a little high at the end off a filter cycle it may be less the next time the filter starts. Low-speed water doesn't pack the dirt into the cartridge like high-speed and when the system shuts off it can fall to the bottom of the tank.
Now that you have cleaned the cartridges, place the green arrow on the starting pressure with the pump at a high speed (full if you like). Now you have a starting point for your system. Just keep track of it from there. Periodically, run the pump at whatever speed you chose to see what, if any pressure rise has occurred and clean when needed

 

[pwa2003]

Thank you!