Can’t Pinpoint Motor Overheating Problem

[oakenshield]

I recently bought a house with an existing pool. I’m not a novice to pool maintenance. I knew going in the pool wasn’t the best taken care of.

The existing motor was running was hot. Very hot. Like can’t touch it for longer than a few seconds. The over temp protection would frequently trip. I let it be for a while knowing it would need to be replaced soon and assumed it was just an old motor. It looked very old.

The original was a Century USQ1152 paired with a PHPM1.0 Jandy Pump. Eventually it went out and I replaced it with the same motor. THP is 1.65. Replaced all the seals, hooked it up and the new motor was STILL drawing 11.5-12.5 amps. The rating for the motor is 8.6 amps and 9.6 max. Obviously the motor was very hot.

I took everything apart and found the part number on the impeller (A0580904) was for a 2 THP motor. Quickly ordered the correct 1.5 THP impeller (R0807202) and also replaced the diffuser (R0445400) even tho it looked good. I verified the part number on the new impeller was correct (A0580903). I don’t know why Jandy uses different P/N in the manual and on the parts…

AND… motor is still overheating. Runs between 10.5-11.5 now. I have a lot of features. I can adjust valves and in the simplest setup (main drain and jets) the motor pulls 10.5. In complex setups it runs 11.5. I assume it has to do with back pressure.

I’ve verified wiring. 238vac before powering the pump and 232vac after power on. Motor is rated for 230vac. The flow is good, it’s actually very good. I don’t think there are blockages. I have a cartridge filter that was just cleaned.

I can’t think of any reason why the motor is still overheating. Should I downgrade to the 1HP impeller (R0807203)? I’ll take any suggestions at this point. Thanks in advance.

 

[ajw22]

Welcome to TFP.

Show us pictures of the motor data plate.

Were you the original buyer of the pump or did you inherit it with the house?

You say the original was a Century USQ1152 paired with a PHPM1.0 Jandy Pump and then say you found the part number on the impeller (A0580904) was for a 2 THP motor. How did that 2HP impeller sneak into a 1 HP pump?

 

[oakenshield]

I inherited the pump. The USQ1152 doesn’t come standard with the PHPM1.0. So at some point it was swapped/upgraded and the impeller must have been swapped/upgraded too. And whoever did the upgrade did not match the impeller properly.

 

[ajw22]

I think you need the 1HP impeller which likely was original in the PHPM1.0

@1poolman1 @JamesW ideas?

 

[1poolman1]

I think you need the 1HP impeller which likely was original in the PHPM1.0

@1poolman1 @JamesW ideas?

The Century USQ line was never the OEM motor on a pump from any manufacturer. That particular motor is an "uprated" 1.5hp motor. You can see from the label and then the rating plate that the motor in the picture is a 1.65THP motor.
The impeller referenced is for a 2hp "uprated," 1.5hp "full rated," 2.25THP motor. That .6THP difference is why that motor is overheating. Get the 1hp impeller if it can be found.

 

[oakenshield]

Thanks I found the 1HP impeller and just put it on order (R0807203)

 

[oakenshield]

I installed the 1HP uprated impeller (R0807203). The current is sitting between 8.8 and 9.4 amps depending on the valve configuration. The motors max current rating is 9.6 so it’s sitting within spec. I don’t expect it to overheat but I’ll be keeping an eye on it. Thanks for the help!