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Discussion Starter · #1 ·
I have a 1.5 HP Hayward Super Pump for my inground swimming pool that is too hot to touch.

The pump is 5 yars old and seems to be running well. The pressure is good and the amperage readings are within specs, however the tempeature of the motor casing is 180 deg Farenheight. but the over temperature switch is not shutting down the pump.

Any ideas why this pump would be this hot?
 

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Idiot Emeritus
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In my experience, it's perfectly normal for a motor to operate too hot to touch.

Look at the nameplate, if it lists 'Insulation Class', it'll be one of the following;

A = 221º F
B = 266º F
F = 311º F
H = 356º F

This is the maximum allowable temperature for the windings, the frame will be cooler.

Does the motor have adequate air for cooling? Are the vents obstructed? Does it get fresh air for cooling?

If the air around it is 104º F or less, and the vents aren't obstructed, I wouldn't worry about it, especially if it's always been this hot.

Rob
 

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Blocked air vents, and/or direct sunlight on the motor can cause that kind of heating.
 

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Pool pumps normal feel hot to the touch.
Pool pumps only have to run 6-8 hours to turnover(filter) all the water in the pool. If you do not have a timer on it, it might worth doing.
 

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Discussion Starter · #5 ·
Blocked air vents, and/or direct sunlight on the motor can cause that kind of heating.
Thanks for the responses,


I took the pump apart again, checked the vent holes and confirmed that there is no blockage.

Ther pump has an insulation class of B, so I wonder if the temperature of the punmp is acceptable?

It isa still running at 180 deg F wilthout tripping out.

This the second Hayward Super Pump that this has happened to ( the last one kept tripping out on high temperature) and the third pump I have put on the pool in 9 year. The last one was replaced under warrantee.

I think I'll just let the pump fail if it is going to and replace it with another manufacturer's pump. Tht's too bad because I thought Hayward was a good brand.
 

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Check the voltage at the motor terminals while operating (with a clean filter, all valves open etc. - you want the minimum restriction to flow for this test). If the voltage is low, that could cause higher than normal operating temperatures. However, 180 degrees sounds acceptable. You can also reduce the load on the pump by partially closing valves on the discharge lines. This increases the pump pressure, but decreases the flow rate which (counter-intuitively) decreases the load on the motor.
 

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Discussion Starter · #7 ·
Check the voltage at the motor terminals while operating (with a clean filter, all valves open etc. - you want the minimum restriction to flow for this test). If the voltage is low, that could cause higher than normal operating temperatures. However, 180 degrees sounds acceptable. You can also reduce the load on the pump by partially closing valves on the discharge lines. This increases the pump pressure, but decreases the flow rate which (counter-intuitively) decreases the load on the motor.
The motor is drawing 8.5 Amps at 247VAC. I don't have any valves on my discharge lines.
 

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The motor is drawing 8.5 Amps at 247VAC. I don't have any valves on my discharge lines.
That voltage is fine, for sure. That current seems high. Unfortunately the manual for that pump doesn't specify operating current, only branch circuit breaker rating (15A). 8.5A at 247V is 2.1kva. Motors typically run about 1kva/hp, so your pump may be substantially overloaded. You could try installing a valve in the pump outlet line and closing it until the current drops to about 6A.
 

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Mpoulton: Please explain " You could try installing a valve in the pump outlet line and closing it until the current drops to about 6A."

Why would restricting the outflow of the pump reduce the current draw of the motor? It would seem to me that he may have an oversized pump for the inlet/outlet piping diameter or inadequate pump for the head pressure.
 

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If this is the original pump than it shouuld be the correct one. If not than maybe someone installed a larger motor to get more capacity.
That may sound good but it will not work since the pool piping is designed for a certain flow rate. The filter, piping and pump are all designed to get all the water filtered in a 6-8 hour span.
Most pool motors do feel hot to the touch.
 

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Discussion Starter · #11 ·
If this is the original pump than it shouuld be the correct one. If not than maybe someone installed a larger motor to get more capacity.
That may sound good but it will not work since the pool piping is designed for a certain flow rate. The filter, piping and pump are all designed to get all the water filtered in a 6-8 hour span.
Most pool motors do feel hot to the touch.

When I moved into the house 9 years ago the pump installed was a 2 HP. When it failed I was sold a 1 1/2 HP . My local pool store told me this would be sufficient. The first replacement pump started to trip out on overtemperature 2 1/2 years after it was installed.


This is a new pump supplied by Hayward under warrantee.
 

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Why would restricting the outflow of the pump reduce the current draw of the motor? It would seem to me that he may have an oversized pump for the inlet/outlet piping diameter or inadequate pump for the head pressure.
As I said, the power requirements of centrifugal pumps are a bit counterintuitive. They require the most power at zero head (maximum flow rate, lowest discharge pressure) and the least power at dead head (no flow, maximum pressure). This is because most of the "work" the pump does is accelerating the water, adding kinetic energy to it, rather than raising the pressure. This actually makes sense if you consider the mathematical relationships involved. Anyway, figure 5 on the following web page shows a pump curve for a centrifugal pump and the relationship between pressure, flow, and power required.

http://www.gouldspumps.com/cpf_0009.html

This only works for centrifugal pumps, not positive displacement pumps.

Bottom line: the discharge restrictor valve is a classic method of throttling a centrifugal pump to keep the motor ratings from being exceeded.
 
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Discussion Starter · #13 ·
My Chlorinater started leaking last year and I removed it. I wonder if this might have an inpact on the water flow since it has been in line since the pool was installed.

I'm going to put a restriction on the line and see what happens.
 

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pump doctor

please check
1-water flow is sufficient
2- prefilter is not cloged
3-bearings need to be replaced
4- cooling fan is performing a suction pressure:thumbsup:
please send mail for further info
 

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The reason the motor is hot is because the motor is built with rolled steel, not cast iron. Heat is dissipated through the rolled steel frame. Rolled steel motors are intended to run fairly hot. Cast iron has ribs running the length of the motor and dissipate the heat over a much larger surface area. That is why cast iron frames feel much cooler to the touch.
If the current is good and there is no overheating, you are fine and need to do nothing but enjoy the pool.
 
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