Pump Unions, Impellers, Bearings & Seals

Pool Pump Unions

Pool pump unions or "couplings" allow you to easily detach and reconnect your pool pump to your pool's plumbing. 

To put it in a nutshell, whenever some sort of repair is required for your pool pump, unions will save you both time and money. The reason for this is that you (or your pool guy) won’t have to spend the extra time and materials to cut out the pipes and hard plumb your pipe back in after the repairs are done. 

Instead of spending hours sawing off pipes, measuring, cutting, and sealing in pipes, all you need to do is give the pool pump union a good twist and you’re good to go!

Pool pump unions are also great for checking and blowing out pipe clogs, especially if your pool pump inlet ports are too tight for you to use a bladder type attachment like the Drain King. 

Pool Pump Unions vs. Regular Plumbing Unions 

You can get regular plumbing unions at your local hardware or plumbing store at very cheap prices but those aren’t designed to withstand the heat generated by your pool pump, which in turn may cause leaks (when they melt) and more headaches in the long run. 

Pool Pump Unions are designed to withstand the heat and the constant vibrations caused by your pool pump. While there may be some pool guys that will argue that unions are only an additional point of failure, we like to counter that with a quality union from a reputable brand, paired with proper installation will prevent any issues from popping up. 

The only thing we can think of that will pose a problem with pool pump unions is the degradation of the union O-ring with the passage of time, but those are pretty cheap and can be easily replaced in under a minute. 

We also have a whole range of pool pump spare parts and accessories that you can browse for any fixes or upgrades which you can check out here.  

If you're planning an overhaul of your existing pool pump, also consider getting a new pump. Most of brands we carry on Mr Pool Man already have built-in pool pump unions from the manufacturer so you don't have to tinker too much with your existing pool pump. Browse our collection of pool pumps with built in unions here.

Pool Pump Impellers

Aside from the motor, the pool pump impeller is the only moving part of your pool pump, which makes it very susceptible to damage. The pool pump impeller spins at high speeds, creating the vacuum that provides the force needed to draw in the water from the pool and pushes it out through your pool filters.

Dangers of a clogged or damaged impeller

Low water pressure or decreased water flow will be the least of your problems if your impeller is clogged or damaged. The low water flow will prevent the pump from cooling down as it operates and there’s a large chance that your shaft seals will melt and fail causing what’s known in the pool biz as a “blown seal” which will lead to a leaky motor, and eventually a whole pump failure.

Symptoms of Impeller Clogging or Damage

Here are some signs you need to look out for when you suspect that your pool pump impeller is clogged or damaged.

• Pool pump surge or pulsing - A clogged or damaged impeller can cause inconsistent suction causing your pool pump to surge.
• Decreased water flow - This can be checked visually via your pool pump lid. Low water flow or if the basket doesn’t fill up with water then it’s very likely that there’s something wrong with your impeller.
• Low pressure - If your cartridge filter or sand filter pressure gauge reads very low pressure even after cleaning or backwashing then there is a possibility that the impeller is clogged or damaged. 
• Loud cavitation noises - If your pump is making noises that are low pitched and extra loud, like an animal growling then there’s a large possibility that your pool pump impeller needs to be looked at. 

Troubleshooting your pool pump impeller

Before buying a new impeller (they can be quite pricey) try and troubleshoot it first. Turn off your pump, clear your pump basket, and with a small wire or if your have slender fingers, try and dislodge any leaves or debris that may have been trapped in the impeller. 

If that doesn’t work, then you may have to open up your pool pump. Check out this helpful article on the parts of a pool pump to help guide you through the process. 

To make the process much easier, detach your pump (this is where pool pump unions shine!) from the pipes and move it so you’ll have a more comfortable position opening up your pump. Remove the volute by removing the seal plate bolts or the clamp band holding the housing in place. Pull back the motor (you may want to let the motor cool down for a few minutes) to expose the diffuser or impeller shroud. Remove the shroud and you should see the impeller exposed. Thoroughly clean the impeller with a wire and reassemble the pump and everything should be back to normal. 

Replacing your pool pump impeller

Follow the steps above to expose your impeller, remove it then slot in the new impeller and you should be good to go.

Important note: If you’re lucky and you caught the impeller damage early then that should be just that. When you encounter impeller damage, also check your mechanical seals, and your seal plate O-ring since these are usually damaged whenever the pool pump overheats due to a damaged impeller. 

If you find that your seals, bearings, and O-rings have been damaged by a pool impeller failure (there’s also a chance that your pump motor has degraded even though it’s not apparent) then it might be a good time to consider getting a new pool pump. The total costs for getting a new impeller and other spare parts can reach upwards of 50% a new pump! And if you add a new pump motor to the mix, well, let’s just say it’s cheaper to get a brand new pump than to spend all the time, money, and effort to fix

Pool Pump Bearings and Seals

Your pool pump bearings and seals (also known as mechanical seals) are the single most important safety feature of your pool pump. While your pump is designed to be exposed to water and the elements, the motor isn’t. The pump bearings and seals allow the motor to spin the impeller to create the required suction while preventing water from getting into the motor compartment and damaging it. 

How to tell if your pool pump bearings and seals have failed? 

A mechanical seal failure has a signature which can be a little bit hard to spot especially if there are other PVC pipe leaks around your pool pump area. The best way to check would be to get on your hands and knees and visually inspect the area under your pool pump where the motor and the seal plate are joined. If there’s staining and water leaking then that’s a sure sign that your seals have failed. 

What causes pool pump bearings and seals to fail? 

The most common cause for the bearings and seals to fail is normal usage. Remember, this part is exposed to heat, vibration and it holds a shaft that spins at speeds of excess than 3000 rpm, so wear and tear will always be a big problem. 

Another cause for bearings and seals to fail is a clogged and damaged pool pump impeller. The heat caused by low water flow can often cause the seals to melt and fail earlier than their rated service life. 

How to replace a pump bearing and seal?  

It’s a fairly detailed process and you can check out our maintenance blog section or our parts of a pool pump post to see exactly where the bearings are located so you will have something to guide you through the process. 

Tip: At the first sign of a failed seal or pool pump bearing, replace it immediately to prevent catastrophic damage to your pool pump. A pool pump bearing and seal kit is only a few dollars, but if it completely fails, you’ll need to buy a new pool pump. Don’t hesitate to reach out to us through the contact us link at the bottom of the page if you have any questions