I replace my 1 1/2 hayward super pump with an the same only difference was the old pump was a 2" connection and the new one is 1 1/2" . I have a DE filter and heater all Hayward products. The old system ran about 13 lbs psi and the new started at 5 lbs psi. I also have to manually play around with the skimmers/main drain so that it would prime.  Once up and running I can open everything and all ok no air bubbles either. So after installation I backwashed added DE did my chemical balance whiich was ok except for CYA. Very low so I added 5 bls of cy. After 4 hrs psi is now 3. I have checked on suction side for leaks and ok. If I did have a leak on suction wouldn't it always produce air bubbles in basket?

Now for the heater. Pool is a 76 degrees. I set the temperature for 82 and heater would come on for maybe 3 minutes and shut off then 2 minutes later it would turn on. This keeps happening and pool is now 80. Wouldn't you think it would stay on continuously until temperature is reached? I thought mayb low flow but I get no lights except the green light when heat is on. No service light. Heater is a Hawward H350FD which is 2 years old. The only thing not replaced is the filter.