Pool pressure problems

[davep]

I have been struggling with my pool for weeks. My initial problem was that my heater would not turn on. The pilot lights stays lit but that's about it. I have replaced the pressure switch but have given up on it for the time being (I'm guessing I have a faulty gas valve).

My main concern has been the pressure. I have a hayward DE filter. My normal (good) pressure is around 10 - 15 lbs psi. It gives me plenty of suction and good flow from my returns. When the pressure would climb above 17, I would backwash. About 17 shuts off my heater (when it used to work). Over the past three to four weeks, my pressure would climb. If I turned on the filter in the evening, by morning it would be over 20 psi with very little flow or suction. I would backwash and add DE as needed to correct this. I would also take apart my filter to hose off the filter material as needed.

When turning on the filter a couple of weeks ago, my pressure went immediately to 22 - 25 psi. I backwashed but that didn't help. I took the filter apart, cleaned it and added fresh DE. I could not get the pump to prime. The pressure shot up over 20 and what DE I added entered my pool through the skimmer and main drain. I put it on recirculate thinking I could clear any obstructions or air blockage. It would not prime at all. I took everything apart again but could not see any problems. I blew out my lines, returns, etc. with a shop vac and put everything together but it still didn't work. I noticed that there didn't appear to be any water going into my chlorinator. I took the tablets out and the system worked perfectly. My pressure returned to 14 psi. I have had my pool for over 12 years and have never heard of chlorinators causing this type of problem. I verified it three times - tablets in and psi jumps over 20; tablets out and psi is below 15. I went to two pool stores and they never heard of it either. I am using the trichlor specified in the owner's manual for a Hayward Cl-200 chlorinator. This past Friday, my pressure problem returned. I replaced the chlorinator. The pressure remained over 20. I took the tablets out and the pressure stayed over 20. I noticed a cracked pipe that goes from my heater to the chlorinator. I replaced that but nothing. I went back to the pool store and was told that I needed to add DE. Since I have no suction, I mixed DE in a bucket, open the filter and added that way. Closed everything up, turned it on and watched the pressure climb over 20.

So far I have replaced the gasket on my Jandy multi-port valve, the gasket on the pump basket, the gasket on the chlorinator, the chlorinator itself, the pressure gauge, and a section of pipe.

Any suggestions? The impeller on the pump feels stiff but I can move it with a screwdriver so I'm thinking it isn't blocked.

[davep]

Just thought I'd update this in case someone else has a similar problem.

I had a pool service company come out yesterday. My problem was caused by a defective check valve between my heater and the chlorinator. This was the one section of pipe I had not replaced.