Pool Pump Questions

General Questions My pump motor hums but will not start. My pump doesn't run. Why does my pump cut off every 5-10 seconds? Can I run my pump without water? How many hours per day should my pump operate? Is there any need to protect my pump from rain and snow? There seems to be so many different pumps, what is the difference between Full Rated, Up rated and Max rated. I have also seen Standard efficiencey models and energy efficient. It all seems a bit confusing? What is the difference between a dual speed and a single speed pump? Click here for more information on Pool Pump Motors

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Q: My pump motor hums but will not start.
A: Turn off the power and check to see if the impeller is clogged with debris.

Q: My pump doesn't run.
A: Check the power, breakers, switches, etc. If you have a timer on the system, make sure it is working properly.

Q: Why does my pump cut off every 5-10 seconds?
A: Your motor is wired to the wrong voltage. Most inground pumps can be connected to either 115 or 230v. Shut off the pump at once and have your electrician check the problem and correct.

Q: Can I run my pump without water?
A: Most pool pumps should never be run without water in them. Doing so causes the pumps to overheat, potentially causing damage to the liquid end and burning out the seal.

Q: How many hours per day should my pump operate?
A: That all depends on factors such as the size of your pool, swimmer load, efficiency of your pump, the filter flow rate, etc. As a rule of thumb, however, a properly sized pool pump should probably run 8 to 10 hours a day in the summer, and 4 to 6 hours a day in the winter to provide adequate turnover.

Q: Is there any need to protect my pump from rain and snow?
A: If you experience a lot of heavy rain where you live, you may want to consider a motor cover. If you use a cover, make sure there is plenty of ventilation around the motor to prevent overheating. In the winter we suggest that you bring the pump inside or cover it to prevent snow or ice from getting on the motor windings.

Q: There seems to be so many different pumps, what is the difference between Full Rated, Up rated and Max rated. I have also seen Standard efficiency models and energy efficient. It all seems a bit confusing?
A:Here is a great article we found on the web which explains the difference between these models:

Up-Rated Versus Full-Rated Pumps and Motors
This is an area of confusion that can be fairly easily explained
What is the difference between up-rated or full-rated? Or is max-rated even better? By understanding a few key concepts, you can clearly understand the difference and make an intelligent choice when selecting the proper pump and/or motor for your pool.

The Motor Plate
The motor plate will have two very important pieces of information
Horsepower (HP) - the horsepower rating of the pump
Service Factor (SF) - a multiplier factor
The Calculation

There is one simple calculation which tells the whole story
Horsepower X Service Factor = Total Brake Horsepower
If you multiply the horsepower rating times the service factor, you find out the total brake horsepower.
The total brake horsepower of the pump is real power rating of that pump or motor.

How Pumps and Motors Get Uprated
The motor plate below lists the following ratings for this 3/4 HP Full-Rated Motor:
Horsepower - 0.75 Service Factor - 1.5
If we insert these factors into the equation, we end up with the following result
Horsepower X Service Factor = Total Brake Horsepower
0.75 (HP) X 1.5 (S.F) = 1.13

Now, suppose you really wanted to take this motor and call it a 1.0 HP motor instead.
You would just INCREASE the Horsepower Rating and DECREASE the Service Factor.
Horsepower X Service Factor = Total Brake Horsepower
1.0 (HP) 1.13 (S.F) = 1.13
VOILA . . . that 3/4 HP Full Rated Motor is now classified as a 1.0 HP Up-Rated Motor
EXACT SAME MOTOR . . . DIFFERENT HORSEPOWER RATING

Some Examples from Motor Labels
The following chart for square flange motors shows how the same motor can be given two different ratings. These motors come off the same assembly line. The only difference is the label that is glued on the motor at the factory.
Motor Horsepower Service Factor Total Brake Horsepower
3/4 HP Full-Rated .75 HP X 1.5 SF = 1.13
1.0 HP Up-Rated 1.0 HP X 1.13 SF = 1.13
These two motors are the exact same thing
1.0 HP Full-Rated 1.0 HP X 1.65 SF = 1.65
1.5 HP Up-Rated 1.5 HP X 1.1 SF = 1.65
These two motors are the exact same thing
1.5 HP Full Rated 1.5 HP X 1.5 SF = 2.25
2.0 HP Up Rated 2.0 HP X 1.13 SF = 2.25
These two motors are the exact same thing
2.0 HP Full Rated 2.0 HP X 1.3 SF = 2.6
2.5 HP Up-Rated 2.5 HP X 1.04 SF = 2.6
These two motors are the exact same thing

All the manufacturers pretty much do the same thing. The 3/4 HP full rated pump comes off of the exact same assembly line as the 1.0 HP up rated pump. All the parts are the same. The ONLY difference is the label.
THE BOTTOM LINE . . . the actual horsepower rating of a pump or motor does not really tell you much.
When it comes time to replace a motor . . . you MUST consider both the horsepower and service factor. This is the only way to insure that you are getting the motor that you need. Consider also the frame size and type of the motor as well. Don't forget to get a pump seal and appropriate gaskets as well.
When you are replacing pump parts such as an impeller or diffuser . . . make sure you match up the exact part number or you may end up with a mismatched impeller or diffuser.
When it comes time to replace your pump . . . look at the flow rating. Pay only mild interest to the HP rating.

Q: What is the difference between a dual speed and a single speed pump?
A:Single Speed vs. Two Speed Pumps

The benefits of a two speed pump have to be seen to be believed. Most pool guys will never even think to recommend this, but it just makes way too much sense to be ignored.
Think about it . . . the two-speed pump addresses the biggest concerns that pool owners have about their pumps, that being cost of operation and quietness of operation.

If you live in California, you may be eligible for a rebate directly from your power company for the purchase of a 2 speed pump (up to $600.00).

Cost of Operation

Energy efficiency is a big issue with consumers and with power companies these days, although many pool guys still don't think much about it.

Consider the following real-life comparison:

Pool #1 - The Traditional Approach Cost: $51.90 per month

This 25,000 gallon pool has a normal 1.5 HP pool pump. It runs 8 hours per day. It pumps about 80 gallons per minute, which means that it circulates 38,400 gallons each day. The pump draws 9.0 amps at 240 volts. At a cost of 10 cents per kilowatt hour, that translates to a cost of $1.73 per day or $51.90 per month to operate the pool.

Pool #2 - The 2 Speed Approach Cost: 19.50 per month

This 25,000 gallon pool has a two speed 1.5 HP pool pump. It runs 12 hours per day in low speed. In low speed it pumps about 40 gallons per minute which means that it circulates 28,800 gallons each day. (Remember that the pool only needs to turn the water over once each day). The pump draws 2.25 amps at 240 volts in low speed. At a cost of 10 cents per kilowatt hour, that translates to a cost of $0.65 per day or $19.50 per month to operate the pool.

The only time you really need to turn it to high speed is for backwashing or vacuuming, or if you need to increase the flow rate temporarily.

In this example you are moving less water, but the reality is that most pumps are oversized and as a result the pools are over-circulated. The 2 Speed pump provides just the circulation that your pool needs at a fraction of the cost.

Keeping the pool circulating a longer period of time each day has a couple of advantages:

The longer periods of circulation will help to reduce the occurrence of algae.

If you have a salt system, you can run the system many more hours per day and get increased chlorine production if needed.

Quietness of Operation
The 1.5 HP pump will typically make quite a bit of noise. This is partly the result of pump noise but more the result of water flowing through the pump and the piping.

The 1.5 HP Two Speed pump on low speed will make very little noise, just a low hum. This is because it is working under much less pressure and the turbulence in the piping is non-existent.

What about Total Dynamic Head?
If you look at the pump curves for two speed pumps, you will notice that when the two speed pump is on low speed, it operates at a very low level of Total Dynamic Head. How can it possibly run, if the pool has a TDH of 50 ft? The answer is that when you reduce the flow, you greatly reduce the friction loss. In other words, you cut the friction loss (as expressed in TDH) of a system by a factor of 4 when you cut the flow in half.

In this example, the pool system which runs at 50 ft of TDH, will now produce 12 ft of TDH. The flow at high speed is approximately 88 gallons per minute, while it is calculated at about 42 GPM in low speed.

WHAT ABOUT SOLAR SYSTEMS? When a pool has a solar system mounted on the roof, a two speed pump may not be the answer. This is because the rise to the roof creates 10 ft or more of static lift, and that number does not change when you put a pump in low speed and reduce the flow through the system. With a solar system, it is often better to use a smaller single speed pump, such as a 3/4 HP pump that will give you adequate lift at all times.

WIRING A 2 SPEED PUMP
One thing that scares people is hooking up a 2 speed pump. It is a little different from hooking up a regular pump. You have to have some way to change from high to low speed.

There are several possible ways to control a 2 speed pump

1. Toggle Switch - Some 2 speed pumps come with a toggle switch on the back of the motor. You will run the pump in low speed normally but manually switch it up to high speed for vacuuming, or backwashing or using the spa.

2. Air Switch - you can buy a two speed air switch to change from high to low speed. This allows you to run air tubing to wherever you want to locate the air button.

3. Two Speed Timer - there is an Intermatic timer (T106) that controls high/low speed. You would use a normal timer to control the on/off function and then use a two speed timer to control the high/low function.

4. Electronic Control - if you have a control system such as a Aqualink or Compool, you can wire up a two speed relay to control the high/low speed function of the pump

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