I have a 3-4 year old Raypak gas heater which just got a new heat exchanger (PH was out of wack and caused massive corrosion). My pool repair person also installed a bypass so I can avoid water circulation through the heater when not in use. The bypass pipe itself does not have a shut off valve; there are valves on the water-in and water-out pipes only. (He said it was not needed since water takes the path of least resistance and will automatically go up through the heater when the valves are open, instead of taking the horizontal bypass pipe). Well, now the heater keeps turning off and on repeatedly. I took out the pressure switch and inspected and cleaned it out. It looks brand new (and is newer than the heater itself anyway---that's another story). I cleaned the filter and all skimmer baskets. I have not checked the thermal regulator, but dont see a reason for it to be broken. I am wondering if the bypass pipe not being completely shut off is causing the water pressure to drop just enough to confuse the pressure switch. My pool guy says this should not cause a problem, but I want another opinion from all of you knowledgable folks!
Any ideas? It's beautiful outside and I would love to start enjoying my beautiful looking pool!