Why is my 0.5 HP Pool Pump putting 1000 Watts of Load on my Inverter?

Supervstech · May 23, 2022

Solana said:
I dont know about that, mate. The pump is designed for 90GPM and with our head we reach 78GPM so the whole water gets turned over in less than 2 hours. If anything that pump is oversized?

The motor nameplate for 230V states 4.4A rating.
If your motor is on 230V, and drawing 5+ amps, it is overloaded, or has a fault.

Hedges · May 23, 2022

wattmatters said:
I'm betting 115 V and 5.1 A = 587 W = 0.79 hp = PF of ~ 0.63

Solana said:
We are running the pump on 230V.

Have you confirmed the voltage with DMM?
Wattmatters has a point about what matters.
The pump says preconfigured for 230V, but it could have been changed when installed.

Hedges · May 23, 2022

Supervstech said:
WTF kind of wiring is that? It looks like you have black, white and green connected in he wirenut. I assumed 115V from that, but you are measuring 5 A… so, what voltage are you dealing with?

Second look, that is just two black wires spliced with tape.
The "wire nut" is actually convolex tubing used as conduit through concrete.

Splice on the left appears to be white and green.
If the circuit provided L1, L2, ground, I guess you could use ground as return to get 115V. Or I should say he (his installer) could, but I wouldn't.

sunshine · May 23, 2022

Solana said:
Deep cleaning done today, exact same wattage.

Can you take out the media and measure under free flow?
Maybe a change to filter size or media used.

Solana · May 23, 2022

Started a discussion in a pool forum as well with some interesting take aways already:

Pentair WhisperFlo 0.5HP (373w) is draining 1200w of power

Pool Pump: 0.5HP Pentair WhisperFlo 90GPM Pool Filter: Pentair EC90, 90GPM 0.5 HP = 372.85 Watts Measured amps: 5 Voltage: 230V When I turn on the pump I see a load increase on my solar inverter by approx 1200 Watts and i am confused by that since the pump should be running closer to 400...

www.troublefreepool.com

"The SFHP is the real HP, which is 0.98.
The 1/2 hp is meaningless.
The HP rating is not the power used but the power delivered to the water.
The typical power draw is about 1,000 watts per SFHP."

Hedges said:
Have you confirmed the voltage with DMM?

Yes, but it's not a stable voltage. Ranging from 228 to 236V.

Supervstech said:
If your motor is on 230V, and drawing 5+ amps, it is overloaded, or has a fault.

A pump expert is coming over tomorrow, i think we're gonna do some dry runs to see the draw etc.

Hedges · May 23, 2022

HP 1/2
SF 1.95
SFHP 0.95

I think you're correct.
But it ought to operate lower than the SFHP most of the time. Maybe as low as HP?
Could be it isn't suitably sized for the backpressure.

Solana · May 23, 2022

Hedges said:
The pump says preconfigured for 230V, but it could have been changed when installed.

Will have that checked tomorrow, thx.

Hedges · May 23, 2022

Your DMM reading confirmed that's not the case. But "unstable" isn't normal. It might change with load or PV backfeed, but most of the time should be stable.
I think SFHP you pointed out is the explanation of apparently excessive power draw.
The one thing you don't know is actual PF; you entered SF in the calculator for power. A meter that actually reads watts would give the correct answer.
I don't have one of those, but I do have a digital scope which can let me calculate watts and power factor less conveniently. What the scope is useful for is to understand waveform; it is interesting my loads aren't just a phase-shifted sine wave.

Solana · May 23, 2022

Hedges said:
Your DMM reading confirmed that's not the case. But "unstable" isn't normal. It might change with load or PV backfeed, but most of the time should be stable.

Oh its unstable because our electricity grid sucks, we don't have any influence of that. Power is generated on the whole island by emergency diesel generators.

Something for our reference I've just found:

ENERGY STAR® Program Requirements - Product Specification for Pool Pumps

Line 38 or Page 2: https://www.energystar.gov/sites/default/files/specs/ENERGY_STAR_Pool_Pump_Spec_V1_Draft1.pdf

Hedges · May 23, 2022

That doesn't entirely agree with the link I found, which said to avoid running at Service Factor load continuously.
Well, maybe doesn't disagree, but what you found said continuous operation at that load won't exceed insulation temperature rating. Different from saying it is advisable, would provide long life.