Caught a pressure gauge climbing slow, turned out to be a lazy check valve

Started by tampapoolguy · · 1 reply
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#1
Customer's filter pressure was creeping up about a pound a week, nothing dramatic, easy to write off as normal dirt loading. Cleaned the cartridge, back to clean baseline, week later it's climbing again same pace. Started looking upstream instead of at the filter itself and found the check valve on the return side barely cracking open, letting a little backflow sneak past when the pump kicked on. Wasn't the filter at all, just made it look like the filter was loading up fast. Swapped the valve, pressure's been flat for three weeks now. Small thing but it saved this guy from tearing into his cartridge every few days thinking he had a filtration problem. Worth checking valve function before you assume it's always the media, seen it a hundred times where the actual culprit is one cheap plastic part nobody thinks to look at.

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#2
Good catch, and that's exactly the kind of thing that gets blamed on the filter every time because a slow pressure creep just feels like dirt loading. Check valves with that spring loaded flapper are notorious for it, the spring weakens or grit gets under the seat and it never fully seats, so you get that little bit of backflow feeding pressure right back into the system. On my own pad I run without a check valve on the return side at all, just don't need one with how my plumbing's laid out, but on my booster line for the Polaris I've got one and I pull it apart and inspect it every spring before I open the pool, takes five minutes and saves you exactly this kind of head scratching later.