Upgraded to 2-speed motor but not enough flow...

[zamazing]

I upgraded the single speed motor of my Hayward Tristar to a 2-speed motor but the new setup (in high speed) is not giving me the same amount of flow as the previous motor. This pump is for a waterfall feature and I'm not getting nearly the same flow rate.

Here are the details of what I changed:

- The wet end is the same and has not changed.
- The single speed was a Tristar Max-rate Pump with a 2.5 HP motor (SP3220Z1M) and 1.04 SF (2.6 Total HP).
- The new motor is a 2-speed full-rate 2HP (model SP3220Z2BE) with a SF of 1.35 (2.7 Total HP).
- I purchased an impeller (model SPX3220C) to go with the new motor. When I removed the existing impeller from the old motor, it was also an SPX3220C, the same exact impeller which I did not expect. According to the hayward manual (see link http://www.hayward-pool.com/pdf/manuals/TriStar.pdf), the impeller for the old motor should have been an SPX3220CM.​

Does anyone know what I may be missing?

 

[mas985]

SPX3220C is for the full rated 2 HP motor which would be the same as an max rated 2.5 HP motor (SPX3220CM). So I think that is ok for both motors.

But if you just changed the motor and not the impeller, then the flow rate should be exactly the same. If the seal was not put on correctly, it would slow down the motor but also the motor would overheat and shut off.

Is the filter pressure the same as before?

 

[zamazing]

Since I had purchased a new impeller, I went ahead and installed it on the new pump.

I measured about 18 PSI at the filter with the old pump, but well under 10 PSI with the new one. I think your suggestion that the seal may not have been put on correctly is on the right track. I do not see any water leaking from the wet end, but there is definitely a big air gap in the strainer when the pump is on, which looks a lot like a suction side air leak. Is that consistent with a bad seal?

 

[zamazing]

SOLVED!! Thanks Mark. I took apart the pump and put it back together carefully this time. It's working just like the single speed. Now, all I have to do is run an extra wire for the low speed portion of the motor and I should be all set.