How to remove air bubble from water pump pressure switch?

[AcidWater]

Shallow well jet pump setup. I can pour water down that little 1/8" tube that comes off the top, but there is a bubble underneath the diaphragm.

All I can think of is to unhook the electric wires from the assembly so I can turn it upside down while filling it. Or do they have a hidden bleeder valve?

Also starting to get vibration noise when it runs, sometimes it goes away before the pump is finished running. So seems that something is worn & out of balance, sometimes finding the balance as it spins.

I'm sure it could be refurbished with a kit, but its not something I could do in an afternoon & of course I can't be without water. Taking it to a shop would take even longer... So can you buy a new pump & return the old pump for a "core" refund or do they just get junked? What if I have a plumber do the whole job?

 

[LLigetfa]

Why do you think an air bubble would be an issue? It can measure air pressure just the same as water pressure.

 

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[AcidWater]

Oh no, air is very compressible. And since the water has air entrained in it, eventually that bubble gets bigger & bigger, which means that the actual water pressure at shut-off becomes higher & higher.

My problem is mud clogging the entry to the nipple, at the top. And I had a very hard time replacing that 3/8 threaded fitting with the nipple, because its tapered. Slicing off the tubing so I could unscrew the nipple got the nipple scratched & it leaked. And finding the specified pressure rated tubing, impossible. The manufacturer can't give me the size spec for the nipple fitting !! Myer pump.

 

[LLigetfa]

Oh no, air is very compressible. And since the water has air entrained in it, eventually that bubble gets bigger & bigger, which means that the actual water pressure at shut-off becomes higher & higher.

You've got to be joking, right? You rewriting the laws of physics now?

What weighs more, a ton of lead or a ton of feathers?

 

[Reach4]

My problem is mud clogging the entry to the nipple, at the top.

If you get mud in the nipple, you probably got mud in the pressure switch. I would replace the pressure switch and pressure gauge. Either clean or replace the nipple and fittings that connect to the pressure gauge and pressure switch.

If you are talking about how to prime the pump, I cannot help with that.

 

[Cacher_Chick]

Years ago I was having a problem with debris in the pressure switch, so I mounted it on the top of a 3' long piece of 3/4" pipe coming off a tee on the vertical. This has worked flawlessly for over 10 years.

 

[AcidWater]

TMI melted down because they lost the bubble in the accumulator ( it "went solid"). Air is "mushy" and smooths out changes in pressure. Prevents water hammer. But with an OFF switch I want it to happen right away when that pressure occurs. As the bubble gets larger it gets worse.

No mud in the switch. It plugs the 3/8" area on top of the unit, prior to the nipple. So to unscrew it to clean it I have to cut the 1/8" hose -- it won't pull off the barbed nipple (without crushing the hose...).

 

[Valveman]

Sure water is compressible, but it doesn't expand and increase the pressure. The pump is the only thing that can increase the pressure. The only place you should have any air is in the "accumulator" or pressure tank. You still haven't described the real problem. What is it that "gets worse"?

 

[Reach4]

TMI melted down because they lost the bubble in the accumulator

TMI usually means too much information... but that is not the case here I think. https://www.acronymfinder.com/TMI.html

If your problem is as I think you think, the problem would be more a restriction before the bubble than the bubble itself. Mostly I don't picture what you have, which is fine. But if you wanted to communicate that, a photo is usually helpful.

 

[AcidWater]

What gets worse is the inaccuracy of the pressure cutoff, it rises. The pump creates pulses of pressure. Solid water transmits them, air muffles it so the switch does not sense enough TIME at the set pressure to trip.

On top of the pump is a square block with threaded holes. Output of the pump, plugged hole for a pressure gage, and the 1/8" hose to the pressure switch located lower down, on the side of the motor

 

[Reach4]

The best place for a pressure switch is very close to the pressure tank port. I understand that jet pumps often have a pressure switch mounted on them, but if the behavior is not good for you now, mounting at the pressure tank is best.

A "tank tee" is a manifold that connects a pressure tank with ports for a pressure switch, pressure gauge, and maybe more.

 

[LLigetfa]

Connecting a pressure switch directly to the pump is a bad idea. Manufacturers do it as a convenience feature, not because it is best practice.

The best place to connect a pressure switch is at the tank Tee. You don't want pulses affecting the switch. You want the true cutoff pressure to turn it off. There are cases where pulses need to be dampened with a special inline damper to mitigate issues.

I think you are barking up the wrong tree.

 

[Boycedrilling]

False cause and affect. A bit of air at the pressure switch diaphragm is NOT your problem.

 

[AcidWater]

Well if the major problem is the pump wearing out -- what about my question re cost of refurb vs new unit?

 

[Boycedrilling]

I don’t know of any place that does rebuilt exchanges on jet pumps. However I did set up an exchange program at an irrigation dealer I worked for 20 years ago. It was an exchange program for end gun booster pumps for center pivot irrigation systems. That way the customer was only down for a few hours instead of days. And they didn’t have to buy a new pump. We just unbolt their pump and bolt on the rebuilt unit. We would then rebuild their old one and have on the shelf for the next customer. But we had hundreds of identical pumps out there. We probably replaced at least one a week during the irrigation season.

If the pump is vibrating, it probably the motor bearing, however it might be something caught in the impeller that’s throwing it out of balance. Similar to a car tire that is out of balance.

I had a customer a couple of weeks ago that had their jet pump quit working. I had them take a photograph of the pump nameplate and motor nameplate in case I needed to order parts. I ended up just sending them to a rebuild shop that had everything in stock and rebuilt the pump while they waited.

I have also replaced impellers and seals onsite when I could order the parts ahead of time.

Costs? Don’t know, but I’m going to guess to replace the impeller and mechanical seal, replace the motor bearing is going to be at least half the cost of a small (under 1 1/2 hp) jet pump.