Cartridge filter pressure went up from 10 to 20

[LeeM2]

When I opened my pool and started the pump I realized (about 10-15min later) that I forgot to unplug returns. 2 out of 3 returns plugs were rubber (1 return and vac) and they just shot out. I've been running pool for a couple week now, don't see any issues other then - my pressure used to be 10 now 20 and I think the return jets used to be a bit stronger than they are today.

Cleaned cartridges again, replaced gauge. no changes.

What could be wrong?

Can 7yr old cartridges be the reason? Should I try to run it without cartridges to see if it goes back to 10?

Could something inside the heater get damaged by increased pressure?I don't use it to heat the water, but it's connected.

I believe this type of problem is the problem only on the return side and not the suction side. Correct?

Thanks

 

[JasonLion]

Something must be different. There are a number of possibilities. You might still have a winterizing plug somewhere that you haven't removed yet. You might have a valve closed that was open last year. There might be a blockage in the plumbing somewhere. The bypass valve in the heater might have jammed closed. Or the cartridges could have gotten clogged with debris that doesn't just spray off. Check at least the winterizing plugs and valves before looking into the cartridges. Then try an overnight soak for the cartridges, see this post for details.

 

[LeeM2]

all winterizing plugs are removed. All valves are open.
heater bypass valve - will need to look into it. Never used the heater, have no idea how it works. Will need to find a manual to see where this valve is located.
thanks for the link on cartridge cleaning.

I guess I could run system without cartridges to see if they are the bottleneck. Correct? If so, what pressure should I expect with all 4 cartridges removed?

Also - is it safe to run it at the way it is until September, or something else can get damaged?

Thanks again!

 

[JasonLion]

If the cartridges are the problem then running without cartridges should give you a pressure well below 10. I would guess around 6. If the cartridges are not the problem then the pressure will be well above 10 without the cartridges.

The whole system is less efficient at the higher pressure, so you will likely need to run the pump a little longer, but otherwise it is safe enough to carry on at 20 psi.