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

[KingKuya]

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 watts. To make sure the load is correct I've measured the amps with the exact same results.

My electrician came already to check all wirings, tightened screws and checked the capacitor. No issues found.

The pump strainer was cleaned today as well as a deep cleaning of the filter to make sure the pump is not doing extra work due to a dirty filter.

Pool Size / Plumbing: 34 cubic meter / 9000 Gallon Pool. Pipe distances are short, pump and water surface are almost level but slightly lower... so gravity can prime the pump.

 

[ajw22]

Motor data plate says max amps 4.4 @ 230V. Volts x amps = watts - 4.4 x 230 = 1012 watts.

The pump is inefficient spinning 3450 RPM for 1/2 HP of water flow.

 

[JamesW]

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.

Assuming a power draw of 980 watts at 230 volts, the amps will be about 4.3 amps.

The motor shows that the maximum amperage at 230 volts should be 4.4 amps.

Anything over 4.4 amps is too much.

Is the motor getting really hot?

What is the voltage measured at the terminals while the pump is on?

Check the power factor if you know how to do that.

Check the capacitance of the capacitor.

If the capacitance is off, the power factor gets worse and the measured amp draw gets higher.

Maybe the shaft is binding.

Spin the shaft from the back while the pump is off to see how easily it turns.


S

 

[KingKuya]

"The typical power draw is about 1,000 watts per SFHP."
Interesting, the first time I hear this. So we're not too far off.

"Is the motor getting really hot?"
We are definetly over the 4.4 max amp, but high temps on the pump were not an issue yet. Its warm, but comfortable enough to hold the hand against the pump casing.

"What is the voltage measured at the terminals while the pump is on?"
Yes, I have a little voltage meter installed that updates every few ms. Initially the voltage drops below 230V during startup but recovers and ranges after from 228V and 236V.

Check the power factor if you know how to do that.

Not sure how yet.

Check the capacitance of the capacitor.

Electrician is coming tomorrow, he will check for sure.

Spin the shaft from the back while the pump is off to see how easily it turns.

No problems, easy to move.

 

[KingKuya]

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

 

[JamesW]

 

[generessler]

Power factor is a good call. 83% would do it. That's a little low for a home, but far from impossible.