Cold Weather Pump Problems

​The change of seasons has brought shorter days and cooler nights. The cool weather can make small pool problems more apparent. Now is the time to deal with these issues before they become a major repair expense.

Symptoms:
The pressure indicated by the filter gauge is low. The flow of water returning to the pool is reduced and the pump is making a sound somewhat like a broken washing machine or a car wash. All of the baskets are empty.
​

Cause:
Air leak on the suction side of the pump.
Air pulled into the pump causes it to lose prime, but only temporarily. This intermittent loss of prime is making the pump cavitate, creating the strange pump noise. Other symptoms can be:

• Air bubbles returning to the pool
• Excess air in the filter tank
• When the pump shuts off, water gushes from around the pump lid. A little is normal.

Troubleshooting:
Rather than going through a lengthy list of likely causes, let's zero in on the least expensive, most accessible part of the pump, the strainer cover (pump lid) O-ring.

The strainer cover o-ring makes the seal between the cover and the pump housing. Without it, the pump will never prime. A  flattened, stiff, or cracked o-ring will sometimes function 

normally.  The problem will pop-up when the pump is required to work a little harder, like:

• Attaching a manual vacuum to the suction
• Attaching an automatic cleaner
• Changing the position of the skimmer/vac port valve
• Setting the pool to spa mode

All of these actions can increase the total length of the pipe or hose the pump has to pull water through. The failed o-ring causes the vacuum forming in the pump housing to break and cause the symptoms described at the beginning. Coldwater increases the likelihood of failure. The o-ring can become hard and fail to compress evenly.

To prevent this problem from popping up at the most inconvenient time, inspect the o-ring every time you clean the pump basket.

• Are there cracks?
• Does it remain flat when removed from the cover?
• Does it appear to be dried out, leaving black smudges on your hands?

If the answer is yes to any of these questions, replace it.

Replacement
Pacific Pool Supply has the most common cover o-rings in stock. To help us identify the o-ring, bring in the pump lid (make sure

the pump will not come on while you are gone!) and/or a picture of the pump itself.
Next, clean the pump cover and sealing surface of the pump housing with warm soapy water. Apply a film of o-ring lubricant (non-petroleum) to the new o-ring, fill the pump housing with water, reassemble the pump and turn it on. ​Make sure the pump stays primed and the water flow is back to normal.