Arimitsu 520 bay pump seal kits only lasting 6 months before leaking

Hi everyone.

At our carwash site, we are using the Arimitsu 520 pumps on our bay stand for high pressure delivery. We are noticing we are only getting 6 months life out of our seal kits which are expensive and we don't know if its normal and if we are doing some different that is causing the premature failure.

We a delivering both unheated water and heated water. The maximum temperature the heated water could 85 degrees celcius (185 degrees farenheit). This is the reading on our hot water tank so inside pump it will be a unknown amount less but will sstill be high. Could this 185 degree liquid be a contributing factore to the seal life?

On the Armatsu 520 pump specifications it states that the max liquid temperature is 170 degrees farenheit and 85 degrees celcius, but this is clearly a mistake as 170 degrees farenheit is 76 degrees celcius. Do you think this incorrect specification is the cause of our equipment failure?



Any advice would be greatly appreciated.

Many thanks,

Alex

Yes, the hot water could be contributing to early failure. Are you sure you are running water that hot? That sounds crazy to me and I have never seen a wash running any where near that temp.

Not an Arimitsu pump guy but hot temps could contribute to premature seal failure. If you are in the self serve business the most common temps to run should be no more than about 120 degrees F. If you can’t turn down your thermostat you should probably install a blending valve to prevent water going to the pump from getting that hot.

Hi guys.

Im editing this reply as I have newfound information due to a miscommunication with my brother. He believe's the thermostat on the water heater is set between 60°c and 70°c (140°f - 158°f). (not 85°C which I originally thought) So we would expect the water temperature entering the Arimitsu would be less than 70°c (158°f). I'll try rig up a inline thermometer if I can find such device.

I also had that idea of using a tempering valve Greg. My brother said they originally had one of these to reduce the water temperature but it mixes directly with our mains supply and thus lowing the pressure of the rest of the site which in turn became a problem. We do not have a hydrovar with storage tank solution on our site.

In Australia I can confirm our heated water must be over 60°c by law. This is to prevent the growth of the Legionella bacteria.

In USA I understand your range is between 49c - 60c (120f -140f) so you are allowed to get away with 120f.

Interesting, during my research I found that temperatures above the 60°c limit may introduce a heat resistant Leginella growth. I do not see any regulations in place to restrict an upper limit to stored hot water, but interesting none the less.


Arimitsu 520 (typo is in the metric max liquid temp)


Cat 310s



So at this point the cause of the leaking seals after every 6 months is still to remain a mystery. And is costing us to small fortune to replace them. We will try to measure an exact temperature of the water before it enters the pump and investigate the best option to lower the temperature

Alex

Is there any way that you are starving your pumps of water? We were going through seal kits about the same amount for our first two years of operations and figured out that when the float valve to my IBA storage tank opened up it would drop our water pressure to our self serves and cause cavitation. We added a gate valve before our float valve to meter the water coming in to our storage tank so the rest of the system wouldn't have such a loss of pressure, and it fixed our issue.

8th Street Car Wash said:

Is there any way that you are starving your pumps of water? We were going through seal kits about the same amount for our first two years of operations and figured out that when the float valve to my IBA storage tank opened up it would drop our water pressure to our self serves and cause cavitation. We added a gate valve before our float valve to meter the water coming in to our storage tank so the rest of the system wouldn't have such a loss of pressure, and it fixed our issue.

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This would depend on how much of a pressure drop we could concider staving the pumps. We have a pressure regulator on each hot and cold serlf serve rail at regulates the inlet pressure for our pumps to 50PSI. According to my brother, this value can drop on very busy days and in particularly did so more if we are using our water softener to soften the water as it produces slightly less pressure than mains.

Reading up a little of cavitation, the vaporization of water inside the pump doesnt occur until 0.34PSI for 20°c (68f) and 3.4PSI for 70°c (158f).
But inside the actual pump it's hard to gauge what pressure the water will be in different parts. As the water velocity increase the pressure lessens.

Looks at Arimitsu specification, I have a feeling they have also messed up the inlet pressure lower limit specification.
-5PSI does not make sense as it would cause cavitation. I believe 0kgf is 0psi. So my question is what is a good minimum threshold for our inlet pressure to be that should not cause any pump damage?


By the way, I noticed you can buy these water pressure loggers. It doesn't seem like a good investment though for something I'll only use once

I don't have any experience with Arimitsu pumps, but I would notice cavitation between 10-20 psi if I recall correctly. I have CAT 5CP2150W pumps and the manual states "optimum pump performance is obtained with +20 PSI (1.4 BAR) inlet pressure..." and also "inlet supply should exceed the maximum flow being delivered by the pump" which should be obvious, but might be worth checking by pulling your supply and holding it into a bucket to make sure you are getting the allotted 4 gallons per minute or more.

I have Cat pumps for all my bays, but I do have Arimitsu on my tunnel prep gun unit, and I hate the Arimitsu. Much higher maintenance than the Cat pumps The Arimitsu needs seals about every two years, but most aggravating is that is I've had several of them explode and throw a valve directly through the pump body.

am86 said:

This would depend on how much of a pressure drop we could concider staving the pumps. We have a pressure regulator on each hot and cold serlf serve rail at regulates the inlet pressure for our pumps to 50PSI. According to my brother, this value can drop on very busy days and in particularly did so more if we are using our water softener to soften the water as it produces slightly less pressure than mains.

Reading up a little of cavitation, the vaporization of water inside the pump doesnt occur until 0.34PSI for 20°c (68f) and 3.4PSI for 70°c (158f).
But inside the actual pump it's hard to gauge what pressure the water will be in different parts. As the water velocity increase the pressure lessens.

Looks at Arimitsu specification, I have a feeling they have also messed up the inlet pressure lower limit specification.
-5PSI does not make sense as it would cause cavitation. I believe 0kgf is 0psi. So my question is what is a good minimum threshold for our inlet pressure to be that should not cause any pump damage?
View attachment 10999

By the way, I noticed you can buy these water pressure loggers. It doesn't seem like a good investment though for something I'll only use once
View attachment 11000

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I'm pretty sure that those temperature codes are for potable water. Many washes in the US use cold water for everything because the wash water is not classified as potable.

8th Street Car Wash said:

I don't have any experience with Arimitsu pumps, but I would notice cavitation between 10-20 psi if I recall correctly. I have CAT 5CP2150W pumps and the manual states "optimum pump performance is obtained with +20 PSI (1.4 BAR) inlet pressure..." and also "inlet supply should exceed the maximum flow being delivered by the pump" which should be obvious, but might be worth checking by pulling your supply and holding it into a bucket to make sure you are getting the allotted 4 gallons per minute or more.

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Thanks for this handy information. I would have to assume that the Arimitsu pumps would be a similar inlet pressure to the CAT pumps. When we get a chance we are going to measure the input water volume and output water volume for 1 minute to make sure inlet is feeding more than its outputting. Its a very good point

Axxlrod said:

I have Cat pumps for all my bays, but I do have Arimitsu on my tunnel prep gun unit, and I hate the Arimitsu. Much higher maintenance than the Cat pumps The Arimitsu needs seals about every two years, but most aggravating is that is I've had several of them explode and throw a valve directly through the pump body.

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We have the Arimitsu pumps in our bays so if we took into account how many hours the pump has been running it may well be simmilar to your tunnel prep pump. So maybe in the bays, Arimitsu only last 6 months. That is very trubbling that you've had sever of them explode! We are considering replacing all our Arimitsu pumps with Cat pumps due to the high maintenance costs

Dan kamsickas said:

I'm pretty sure that those temperature codes are for potable water. Many washes in the US use cold water for everything because the wash water is not classified as potable.

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Hi Dan. We currently are using mains water which is potable water here, if by potable you mean drinking water. But soon we will be reactivating our water softener so the bay pumps will be pumping softenened mains water. Im not sure however if softened water goes it our water heater to supply the hot water rail though but i think it most likely would for improved lathering and prevent calcification in equipment