2 speed spa pump only runs on high

this is my first posting.

I've searched the website tried the various recommended solutions for similar problems but with no success, so I've decided to post with a little more information.

Background: The motor is about 12 years old, an EMG 90 2-4 motor. Low speed 1440 rpm and 0.45 Kw (runs the circulation system and heating flow system) and high speed 2830 rpm 2.36Kw.

It stopped working and when I took it out, the junction box on top was 'burned out' and the two capacitors (16uF and 35uF) were burned out and almost unrecognisable, likewise the relay.

I purchased a new junction box, relay and capacitors from a well known Hot tub spare parts company and installed them.

It worked fine (on my work bench) for 3 or 4 times turning on and off and running for about a minute each time (without the wet end attached) then stopped working. I noticed the new relay was burned out. On closer inspection I realised I had been sent a 24V not a 240V specified relay !! There was an error on the Spare parts company website which I have made them aware of. They sent me without charge a replacement 240V relay.

Now when I switch it on to the high speed, it works instantly without problem. But on the low speed, it hesitates and one might say "wobbles / oscillates" about 10 degrees between clockwise and anti clockwise then does eventually spin in the right direction. Naturally it hums till it starts turning.

Once I refit the Waterway wet end (with new bearing and impeller also installed), it simply doesn't have enough "grunt" to overcome the slightly increased load of the wet end. It will though spin and continue to spin if I give it a manual spin to 'start it off'. Once spinning, I cannot slow the motor by applying a little resistance. The torque seems good.

I have checked for any earth loop / leakage from the armature wiring to the case and there is none.

I've checked the two capacitors and they both read accurately 16.2uF and 34.9uF respectively

On reflection a few weeks before the 'total failure' the slow speed pump setting was erratic.

I have also had an electrician check the RCD and MCB supply for the tub (its on its own circuit) as I was worried as to why the circuit breakers hadn't cut in. He can not find any faults.

I cannot identify any brushes for the motor, I suspect it is a 'brushless' motor. All the motor hearings are silent and smooth - no 'grittiness' and without the wet end on run smoothly and the motor rotates freely if given a twist by hand.

My questions: Have I failed to check anything ? Is it likely to be some of the windings on the motor which have begun to fail and hence I need a new motor ?

I don't want to potentially waste more money replacing the capacitors again if they are unlikely to be faulty, but a new motor is expensive if I may have missed something.

You advice and suggestion would be greatly appreciated.

Thanks in advance for your help and patience, Graham

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Spa and Hot Tub Pumps. They provide the circulation for the spa filter and heater and give an extra boost when turning the spa jets on high. And when the spa pump ain't happy, ain't nobody happy - that's because without water flow, there is no filtration, no sanitation and no heating.

Spa pumps need to operate every day to maintain clean and hot spa water - so when your hot tub pump has problems, it's an emergency. If your spa cover is kept on, you may have 1 day before it cools off and perhaps only a few days before bacteria and pathogens begin to thrive.

Shock the spa with your favorite spa shock when the sanitizer level gets low. You can continue using a granular shock Leisure Time Spa 56, or a floating spa sanitizer dispenser with tablets for several weeks, but if you go without filtration longer than a few weeks, you should consider draining the spa after your pump troubles are fixed.

Some spas have two pumps, one is the circulation pump and the other is the jet pump. If you have two pumps, chances are it's one or the other - either your jets don't work, or the spa circulation isn't working. Spas and hot tubs with one pump usually have a 2-speed motor, operating on low speed most of the time, and on high speed when using the tub with the jets.

Spa Pump Trouble F.A.Q.

Here's a simple way to troubleshoot your spa or hot tub pump. Hot Tub Blogs should do this more often - These are our most Frequently Asked Questions about spa pump repair.

Q: My Spa Pump is Dead - No Noise, No Action!

A: When you hit the switch or button, and you don't hear your spa pump come on, there are a few things simple things you can try.

First, are other equipment items powered, are the indicator lights on? If not, the Circuit Breaker may be tripped. Second, the GFCI breaker may have tripped. Look for a red "TEST" button on an electrical outlet near your spa equipment. If the GFCI was tripped, but the spa still won't come on, check the system fuse in the spa pack panel. If you replace the fuse and it pops again, you have an short in the wiring equipment of your spa.

Third, check your time clock or remote spa controller, if you have one, to make sure it is not over riding the switch you are using. Fourth - is a faulty switch you are using to turn on the spa pump. Air switch buttons are often used on older spas, and you may have a problem with the switch or the hose. Modern
air switches are electronic, and you can test the power coming in and out of them to determine if the switch itself is faulty.

Q: My Spa Pump is Not Pumping!

A: If your spa pump is coming on, but not pumping any water here's some steps to troubleshoot.

First, have you just refilled your spa? If so, there is probably and air lock in the hot tub. In some spa systems, when you completely drain the spa, air gets trapped in the pipes and equipment. You need to bleed the air out and replace it with water before the pump can catch prime.

To bleed air our of your system, first look for a drain plug on the pump and filter. Place a small pan or cookie sheet underneath to catch any water. Slowly open the drain plugs until water begins to run out. If you don't have drain plugs, you can slowly loosen the union on the pump (but don't remove it, or the o-ring may pop out of place). Listen for escaping air, and then once the water begins to drip, you can tighten the union up again.

Second, if your tub is full, and still no water runs out, look for any closed valves before or after the pump. Third, is something blocking the lines? Look for something stuck in the skimmer or blocking the spa drain. Fourth, is the water level high enough? Low water will allow the skimmer to suck air, and cause the pump to lose prime. Fill spa to the middle of the skimmer opening.

Q: My Spa Pump Only Works on High Speed

A: First, rotate your timer clock and turn up thermostat to high to see if this resolves the problem.
Second, check the power at the low speed and high speed terminals, which should be either 110V or 220V, +/- 10%. Third, check the air switch button that you push to switch speeds. Check for voltage coming in an out of the switch, or for mechanical air switches, check that the device is not clogged with debris or insects, and that the air hose is in good shape and connected on both ends. Fourth, the mechanical switch in the back of the motor could be stuck in the high position, due to broken parts or insect infestation.

Q: My Spa Pump Only Works on Low Speed

A: When your 2-speed hot tub pump only works on low speed, and never kicks into high speed, there are four possible solutions to check.

First, if you are pushing an air switch button, check that the air hose is not crimped or disconnected. Newer, electronic air switches can be tested with a multi-meter, to see that power is passing through, on both sides of the switch. Second, If the pump was recently replaced or rewired, the wires could be reversed on the back of the motor.

Third, is the switch in the back of the motor, that changes to motor from low speed to high speed. With power off, manually operate the switch, looking for something loose, broken or misaligned. Insect or ant infestation could also prevent the switch from operating correctly. Fourth, is the contactor/relay that switches the pump speed. With power off, make sure that the connections are tight, and the terminals are not rusty or corroded.

Q: My Spa Pump is Humming, and Then the Breaker Trips

A: If your spa pump never actually turns on, it only makes a low noise, until the circuit breaker trips, check these things.

First, would be the capacitor on the motor. This cylindrical "battery" provides extra starting power, and these can go bad after many years. You can test the capacitor, or simply replace it with an identical size. Second, Check the shaft for rotation. If you have an open volute, where you can see the shaft, use straight pliers to manually turn the shaft, to rule out a locked up motor, or something stuck in the pump impeller. Third, Check that input voltage is correct, either 110V or 220V, +/- 10%. Fourth, it is possible that the breaker itself is in need of replacement.

Q: My Spa Pump is On, but Barely Pumping

A: First, check the spa filter, it may need cleaning. Second, look for any obstructions in the skimmer or over the drain cover. Third, something could be clogging up the pump impeller, especially if a spa cover is not used, and lots of small debris has entered the hot tub. Fourth, an air leak, before the pump can cause this issue. Check the union in front of the pump, and look for any water leaks when the pump shuts off.

Q: My Spa Pump is Making Loud Noises

A: There are a few types of funny noises that a hot tub pump can make - none of them good.

First, if the noise is a screeching, high pitched whine, the motor bearings could be failing. Bearings can be replaced, or if the motor is very old (more than 5 years old), you may consider replacing the hot tub motor. Second, if the noise is a low pitched, grumbling noise, the pump could be starved for water. Check that the valve in front of the pump are open, and that nothing is clogged in the suction lines including the spa filter. Third, a rattling noise could be vibration that can be solved with a rubber pad beneath the pump. If something is broken inside the motor, it doesn't take long (at 3400 rpm) for broken spa pump parts to be worn down to nothing. In this case, the noise would not last more than a few minutes.

Q: My Spa Pump is Leaking Water

A: First, and most probable, is that the shaft seal of the pump has failed. This is located behind the impeller, and would leak along the shaft, just behind the volute. Second, is the union on top of the pump. If water is dripping or spraying from where the union connects, the PVC threads may have shrunk (from running pump without water), or the threads may be loose and simply need to be tightened. Third, if either incoming or outgoing unions were loosened recently, the internal o-ring may have come out of place, and not be positioned properly. Fourth - is the o-ring that seals up the impeller housing, or volute. Dry-rotted, out of position, or possibly loose, along with loose screws around the face of the pump.

Happy Hot Tubbin’

Daniel Lara
Hot Tub Works

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