I have a 2 hp Sta-Rite Dura-Glas II pump (model P4RA6G-188L). I'd like to lower the output on the pump and am considering replacing the 2 hp motor with a 1 hp motor, the A.O. Smith USQ1102 for example. My thought is to replace the seal and o-rings but reuse the impeller. Are there potential problems with doing something like this, such as overloading the new motor?
Change pump motor from 2 hp to 1 hp - any problems?
- Thread starter Silverhawk
- Start date
Yes. You can not downsize the motor without also downsizing the impeller ... which may or may not also require additional hardware changes, like the diffuser in the pump
{You can oversize the motor for an impeller though without problem.}
{You can oversize the motor for an impeller though without problem.}
Looking at my owner's manual the 1.5 and 2 hp Dura-Glas II pumps both have the same impeller (#C105-238PDBA). Based on this I should be able to drop down to a 1.5 hp motor without any problems, correct?
- Jun 20, 2012
- 439
Silverhawk said:
I would be careful about this. As far as I know (and I may be wrong), they are not the same impellers. That said, you need to compare the service factors on the old motor, with the service factor on the proposed new motor.
In other words Service Factor (SF) x HP = real HP, so a 2HP motor with a SF of 1.1 = 2.2 HP. A 1.5 HP motor with a SF of 1.65 = 2.475 HP.
Why do you want to do this? If it's to reduce flow, you need to reduce the impeller size. If it's to reduce energy consumption, reducing the motor size will have virtually no impact, and may lead to excessive wear and tear on the motor.
You're probably better served by doing more research and going to a two speed pump motor with the proper impeller.
I just went back and reread what you're wanting to do. Changing the motor won't do what you want. The wet end (and plumbing) is the determining factor in how much a pump works. In order to lower the output (GPM) of the pump you'll have to change the impeller and possibly the diffuser. Even keeping the same motor and changing the wet end will accomplish what you're wanting to do.
If you keep the same impeller and went to a 1½ hp motor the current draw will be the same.
If you keep the same impeller and went to a 1½ hp motor the current draw will be the same.
- May 3, 2007
- 16,815
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
The reason they have the same impeller is because they actually use the same size (Label HP * Service Factor = total HP) motor. One is full rated and one is up rated.Silverhawk said:
If your goal is to reduce energy costs, what you really want to do is drop the impeller by one or more sizes. The motor does not need to be changed.