What to do About a Surging Hot Tub Pump


Surging is a hydraulic phenomenon in which pressure difference develops rapidly within a plumbing system following a sudden change in fluid flow rate.

For instance, the rapid closure of a water valve will cause an instant rise in pressure beyond the valve due to compression. On the other hand, a negative pressure develops just downstream of the valve. This results in temporary separation of the water column preceded by a backward flow towards the valve which is dependent on the pressure gradient.

Besides valve closure, improper filling technique, and sudden pump starts or stops are the other causes of pressure surges in a fluid system. Power failure is the most common facilitator of surging as it leads to sudden stoppage of pumps. Significant pump surging can lead to equipment or pipeline damage if the system is not protected or controlled.

While some effects of surging such as loose pipe joints may be regarded as minor, the cumulative impact may be disastrous with risks of system contamination both from the ground and backflows.

How Can You Fix A Surging Pump?

For a hot tub, surging may be caused by clogged filters or pumps and low water levels. To fix a spa surge, first, you need to check out for any debris in the filters that may be causing the blockage. Thoroughly clean the filters before restarting the pump.

If filter cleaning does not work, check the spa water level and act accordingly. Low water level permits air entry into the system through the jets causing surges. However, if both the filters and water quantity are okay, then the issue could be within the pump. You need to contact a technician to fix the issue. Noteworthy, old pumps may require replacement.

What Is The Difference Between Air Lock And Surging?

Air lock occurs when air enters the pipeline system from either a cylinder vent, a tank (if the fluid level goes too low), or during heating of the liquid. The air then accumulates at high points and consequently restricts fluid flow within the pipework. Unless greater pressure can be generated to push out the bubbles, the airlock will require manual elimination.

On the other hand, surging results from a sudden stoppage of fluid flow in high-pressure systems. It leads to a temporary fluid column cut-off or cavitation within the pipework which is followed by reverse fluid flow whose intensity depends on the pressure gradient. Causes of surging include closure or opening of fast-acting taps, spring-valve closure, and rapid start or stoppage of pumps.

The effects of surging can be more severe compared to air locking as it can break pipes and damage pumps.

How Do You Remove Hot Tub Air Lock?

After the routine quarterly cleaning and refilling of your spa, you turn on the jets ready to soak but nothing comes out. You check the pump and yes, the motor is running. There is only one possibility- the hot tub is air locked! But this is not a major tub issue so you don’t need to call an expert.

Removing the hot tub air lock is a simple task that takes only a few minutes despite the method you use. However, you need to switch off the heater before you begin to prevent overheating. Notably, some modern spas come with a bleeder valve that facilitates faster and easier elimination of the airlock.

Burping is the first method you can use to drive out air from the system. It involves opening the jets entirely then turning them on and off at intervals of about 10 seconds until air bubbles out of the jet. If bubbles do not come out after 3 cycles, try the second method which involves removing air from the pump using channel lock pliers.

Editorial Staff

I'm Adnan Sabanovic, the guy behind Hot Tubs Report. I've had a chance to enjoy hot tubs last few years and have really become interested in owning one of them. Nearly every weekend you'll find me spending time with my family or playing sports. If I am not doing that then I'm here writing about tubs on Hot Tubs Report. This blog is a research for my first hot tub which I decided to document and share publically so others can benefit from it as well.

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