Why is FloJet slowing down?

[Rudy]

Per the advice of users on this forum, I replaced the ARO diaphragm pump with a FloJet for the presoak pump on my touchless automatic.

I've had great luck using the FloJet as a prosoak pump for my 3 bay self serve.

In the automatic, however, it slows down to about 1/2 spreed when we have ultra busy days. It reminds me of the ARO's icing up before I put water seperaters (centrifugal type) in the air line.

What causes the FloJet to work fine if there's a break between cars, but it slows when we are washing car's nonstop (duty cycle maybe 40 seconds on and 3 minutes off)?

Ideas? (BTW, it's mounted under my stainless supply tanks just off of the floor. Would a higher mounting location make a difference?)

 

[under pressure]

you must be having a low air pressure situation when things are really busy, get a larger air compressor.

 

[MEP001]

That would be my first guess too. Have you checked that the pressure isn't dropping?

 

[Earl Weiss]

Second guess is a restriction n the supply line. Any chance their has been a kink or buildup of Gunk?

 

[Rudy]

Thanks for the suggestions...

I don't think air is the problem. I've got Two compressors connected in series....and the second one never comes on. There's an 80 and 60 gallon tank of air.....which is overkill. Also, I'd likely see the issue on other pneumatic devices....which I don't.

I installed a new supply line as part of the troubleshooting. The output line was disconnected, blown out, .....check valves checked for debris......nada.

I'm down to the pump. Either I got two bad pumps or something weird (like internal icing) is going on.

What stumps me, is the fact that after a rest, it will work for a while......

Today is going to be a killer day. Can I plumb two G57's in parallel to get through today?

 

[PaulLovesJamie]

I also think its the air supply, but dont forget that volume & pressure work together, it could be either one.
Flojets are easy to swap out, for a busy day (like yesterday & today!) if I was having a problem with a flojet I'd just swap in a new one and do detective work monday when things are slower. That would also eliminate the pump itself as being the cause. (unless its undersized)

One other possibility would be back pressure, eg an obstruction or restriction on the downstream side.

 

[Rudy]

I've already swapped them out (Both were ordered at the same time...so makes me wonder???). The behavior is the same with either pump, so either they are both bad...or there's a common cause.

Thanks for the ideas. Keep them coming...

 

[dewey9876]

Look for moisture and or water in your air, Flow -jets don't handle it well.

 

[MEP001]

Yes, you can plumb Flo-Jets in parallel. I've seen as many as 16 in a single bank.

 

[Uncle Sam]

Rudy,

You have eliminated many questions by changing the parts of the system that you have already done. My idea is that the air is reasonably cold where you are located, so when high pressure air to drive the pumps expands (exhausts) from the pump it gets even colder and forms ice with any water vapor in the supply air. This would probably slow down the piston the runs the pump. In between cycles the ice will melt and the pump will go back to working normally. The faster the cycling is done, the less chance for the ice to melt.

On a cold day in our shop we get the same thing happening to our air operated brushers or cutters. The air motors get so cold we can hardly hold them; they do slow down too.

Uncle Sam

 

[Washmee]

You have the same problem as John Racine,http://forum.autocareforum.com/showthread.php?t=4715, too much moisture in the supply air. With drier air your problem will disappear.

 

[Rudy]

We are getting through the day. I salvaged a well over worn ARO diaphragm pump from the "just in case" junk pile, and so far it's keeping up.

I'd really, really like to know the WHY. The internal icing is still my best guess.......

 

[soapy]

Does your flojet have a muffler system on it? I have seen these plug up with ice when cold air is run through it. The small holes in the muffler will plug fast in cold weather. You can remove the muffler and the pump will be a bit louder but will work. It does sound like a air restriction problem.
Cheveron makes a product called Ban ICe that you can put in the air lines or compressor tanks to help dry out the air during cold weather situations.

 

[Rudy]

To get the air dry enough, will a coalescing filter do the job.....or is it necessary to get a unit with a heat exchanger that actually "dehumidifies" the air?

 

[Washmee]

To get the air dry enough, will a coalescing filter do the job.....or is it necessary to get a unit with a heat exchanger that actually "dehumidifies" the air?

The best ones are actually refrigeration units. Somrthing like this;



http://www.grainger.com/Grainger/items/3YA49?Pid=search

 

[Ric]

The best ones are actually refrigeration units. Somrthing like this;



http://www.grainger.com/Grainger/items/3YA49?Pid=search

That unit did the trick for me. After installing it in my tunnel I rarely had a flo jet failure and my air operated doors also quit freezing up. All other air operated cylinders and devices benefited also. It was worth the money.