Priming
It's a common term used by pool professionals: "priming a pump." But what does that mean?
When a pump has prime it means that it it is completely full of water from the suction side of the plumbing, inside of the balut and housing, all the way to the return side of the plumbing with little or no air bubbles. Pool pumps are designed, of course, to move water very efficiently, but they are not very good at moving air. When air is present in the suction lines, it can actually STOP the pump from moving anything. Air is the enemy of pool pumps.
In this article we will show you the most common reasons for air to enter the system and what can be done to fix it. Just follow the steps to get your pumps primed and to have your pool circulating normally again.
Step 1 - Check the water level in the pool.
This seems obvious but it is often overlooked, a maintenance person may be so determined to find a problem in the pump room that they don't check the pool itself!
If the water level is below the skimmer openings, the pump is likely pulling air from the skimmer suction lines. And as mentioned before: air in a suction line = no prime.
Be sure that the water level of the pool is about at the middle of the skimmer openings and try to turn on the pump again. If there are no other existing air leaks you should see water fill up the pump and your flow rate should be normal. If not, move on to Step 2.
Step 2 - Check the trap baskets.
Cleaning the trap baskets ( skimmer baskets, pump baskets) should be part of the regular pool maintenance routine. If the trap baskets have not been emptied for a while, they could be completely full of debris, which can cut off the flow of water to the pump. Additionally, a skimmer basket that is full could create a "dam" of debris around the opening of the skimmer which can stop water from flowing into it and could allow air into the skimmer suction line.
Be sure that all skimmer baskets and pump baskets are emptied.
After emptying the pump basket, place it back into the pump and add water. With the pump lid off, turn the pump on and watch the water inside of the pump. If you do not see water drop immediately upon turning on the pump, there may be problems with the impeller and you can skip to Step 4.
Step 3 - Check SVRS system.
SVRS stands for Safety Vacuum Release System. In the general consensus, these systems are required for commercial pools.
SVRS systems are designed to detect a change in vacuum pressure from a swimmer blocking a suction line such as the main drain. When the SVRS detects this sudden change of vacuum pressure, it will send air into the suction line to disable the strong suction, or "pull," of the pump, essentially releasing any person or thing that has covered that suction line.
When these systems are tripped, they need to be manually reset. so that the pump can continue to pull water as it normally would.
Make sure your SVRS isn't tripped, the reset process depends on what type or model of SVRS is installed in your system. In most cases it is a simple button or a toggle type switch. Check the owner's manual for your type of SVRS.
Step 4 - Check the impeller.
The impeller inside of the pump works like a propeller to move the water through the pump housing. Sometimes, if the pump basket is damaged, debris can get caught in the blades of the impeller and cause a clog. Impellers can also be clogged by fibers that come off of non approved swimwear. This is why clothing such as jeans or cotton shirts are not allowed in commercial pools.
With the pump lid removed, empty any debris that may be in the basket and also remove any fibers that may be woven into basket itself. Place the basket back in the pump and fill the pump with water. With the pump lid off, turn on the pump. The water should immediately drop down upon turning on the pump. If not, the impeller may be clogged or damaged.
To check if the impeller is clogged, first make sure that the breaker for the pump is turned off, making sure the pump is not on a timer and there is no risk of the pump turning itself on. You can use a tool such as a screwdriver to reach into the hole at the bottom of the balut and feel the blades of the impeller. If the impeller is clear, you should only feel the plastic blades on the tip of the tool. If the impeller is clogged, you will likely feel the tool dig into soft debris. If you feel this, you can start digging this out with the tool. It may be a little tricky but little by little you can pull out most of the material that was causing the clog.
If you cannot remove all debris from the outside, using this method, it may be required to disassemble the pump down to the impeller to verify that there is no more fine debris (gravel, seeds) in the channels of the impeller.
Replace the basket and fill the balut of the pump with water again. Then turn on the pump and watch if the water drops. If the water drops immediately, the impeller is clear and functioning normally. If the water does not drop, even after cleaning it out, the impeller may be damaged or disconnected from the motor and may need to be replaced.
Step 5 - Check for air leaks on pipes/valves.
If none of the above steps fixed your prime issue, it's likely that air is getting into the suction lines via one of the glue joints or where the pipe threads into the pump balut, which is the most common area for air leaks.
Silicon can be applied directly on the glue joints while the pump is running, if there is a suction leak, the negative pressure from the pump will pull the silicon in and hold it in place, which will stop the air from entering. You can start with the pipe that threads into the pump balut and work your way down, applying silicon to each glue joint until you pinpoint the leak(s). If you see the pump suddenly start pulling water as it's supposed to, that means there was an air leak and you have just sealed it with silicon. Apply a liberal amount of silicon to that glue joint to ensure that it stays sealed.
If you have valves installed on your suction lines, it may be necessary to disassemble them and check the O-rings and any other seals. For Jandy valves, the most common air leak comes from the small O-rings on the stem of the valve handle. Any broken, cracking, or worn O-rings should be replaced. It may also be necessary to apply silicon or gasket lubricant to certain O-rings
If you have sealed each glue joint and the pump still does not pull prime, move on to the next step.
Step 6 - Check/Replace shaft seal.
Pump shaft seals are two pieces designed to rotate over one another while still providing an airtight/watertight seal. This is how you can have an impeller attached to the shaft of the motor and spin without water simply leaking out from the hole where the shaft enters the pump housing. Shaft seals can wear out over time and lose their integrity, causing water to leak and can make it very difficult for the pump to pull prime.
There are many different makes and models of pool pumps and each use a specific type of shaft seal. Be sure to get the shaft seal that was designed for the exact model pump installed in your pool system.
The pump will need to be dismantled by your pool professional. This is a good opportunity to check the condition of the impeller. An impeller with broken blades or with any major damage or wear will need to be replaced.
After the old shaft seal is removed and the new one is set in place, the pump can then be reassembled by your pool professional.
Once the pump is completely reassembled, add water to the pump balut and close the lid before turning the pump on. Pumps need to contain at least a small amount of water before they can pull prime.