scratchinging my head over domestic water pump issue

[Amberjack]

Three years ago I upgraded Amberjack's salon. It was a wonderful improvement and for those contemplating that step I recommend it as a solid return on both financial and emotional investment.

While the salon was opened up I decided to proactively replace the Par Jabsco domestic water pump which was running fine but was 12 years old. We finished the project in early summer and took off on a four week trip into Canada. On the way home the new pump failed and I replaced it with the original pump which I had kept on board as a spare. After wrangling with the retailer and being told the carpenter would have to return the pump (he couldn't find his receipt) I took the hit and just bought another pump and installed it that fall. Next year on vacation this pump failed. Back in went the trusty original pump and now armed with a receipt I went to work on the pump retailer and then the manufacturer. The manufacturer's technical support person was a nice enough guy and helpful but after he put me through his paces he finally threw up his hands and sent me a replacement n/c. He assured me this pump had been tested at the shop before shipping.

This third new pump followed the same pattern: they run well at first, nice and crisp sounding. Then they start to labor a bit over maybe two or three weeks of use, then they start popping the breaker or if I keep resetting the breaker blow the fuse.

I can't figure this out and its driving me nuts. Now I have three almost new pumps sitting on my work bench and the (now) 15 year old same model pump happily ticking away on the boat.

I've confirmed free water flow to the pump intake, replaced the breaker and upsized the fuse from 7.5 amps to 10 amps (spec is an 8 amp fuse for a 6 amp motor). When I put a meter on the last pump as it was failing it quickly jumped to 10.5, 11, 12 amps. When I ran the pump on a hose direct from a bucket of water to confirm it wasn't a water restriction issue it started to jump violently as it approached pressure, then blew the circuit. This bucking likely happened with the other pumps but wasn't noticeable because those pump mounts were fastened down and the pump under the settee. I'm pretty sure it is wired in correctly and the factory tech says that reversing the wires wouldn't cause this issue anyway.

It almost feels as though the pump motors are defective and wearing out quickly, but three of them? Same for the pressure switch, three in a row can't be defective.

I'd really like to put the trusty old pump out to pasture and use one of these almost brand new pumps. Maybe I'm too close to this issue and can't see something obvious. Any ideas?

Two of the three new, failed pumps


Pump motor specs


One of the new pumps down in the "hole"

[Yannis]

Doug,

I change two pumps average each and every year if that comforts you.

Most of the times it is the switch that fails, the one that is on the pump. Apparently ALL those cheap switches are 220 volt and are asked to do a 12 volt job, whatever that means.
I purchase those little flimsy switches by the bucket and save money on the whole pump.
I never saw any pump like yours, these seem like NASA rovers to me.
I also use 11-12 liter/4 gallon pumps.
Mine are getting wet, or humid, so they are short circuited mostly.
I can explain all this by my living aboard and giving them heavy use (dishes, showers, rinse, cook etc).
Mega inconvenience, I agree, especially when you are covered in shampoo...

[Bruce]

Doug,
my biggest issue back in the day were pressure switches failing and the pump pumping till the pressure got so much the motor would lock up but power was still being sent to motor and it would damage comutator and brushes.

I gave up on the newer pressure switches and either replaced the pump with a shurflow, or installed a better pressure switch on the pump outlet.

Those older par pumps used to run forever. Starting in the 90's they started having issues.

[Rawleigh]

Could you just use a conventional 110v well pump pressure switch in the 12 volt system instead? It may be a little bulky, but it ought to hold up OK.

[Carl]

They do not last like they used to...

Debris, algae or... when that switch goes and they continue to pump to higher pressure, they die quickly.

I have 2 systems with those pumps. One in my shop to cool the TIG welding torch. I used to get several years from a pump then that dwindled to months. I found a little algea in the recirculating tank was a huge cause, so installed an inline filter.
Much better...but the pressure switch hanging up was my next problem. When it failed the motor pumped like hell. I added a bypass so the motor can run constant and never build high pressure. With the filter and bypass, I get a good 3-4 years from a pump. But at times I run it for 8-hour days, weeks on end...so not so bad. I keep a spare on hand.

In the boat, I had a similar issue related to the pressure switch hanging up leading to overloading the pump causing it to die an early death. Instead of a bypass, I tried installing an accumulator tank in line with my dads' recommendation. Of course, my pump will most likely die today because of what I am about to say...since installing that tank 7-8 years ago the pump and switch have worked without issue. FYI- my tank is no larger than a softball.

[Amberjack]

Thanks everyone, you're pretty much confirming what I had been thinking which is a pressure switch problem. I hadn't realized the pressure switch issue was burning out the motor although that tracks with what I was hearing. The motor sound changed over a few weeks from fresh and crisp to labored. At least now I won't waste time and money replacing the pressure switch on a pump with a burned out motor. I'll cross my fingers the old pump continues to tick along and will use the newer ones as a source of spare valves and bladders.

It is amazing they continue to sell defective pumps at $450 retail. This has been going on for a few years and they certainly know the pumps fail within weeks.

Carl, I do have a pressure tank on the system, the small ShurFlo tank which sounds like what you have. It makes a big difference and cuts the pump cycling maybe in half. Tricky figuring out what level to pressurize it to. I think 20 psi which is the kick on pressure for the pump. I'm going to look at that some more. There had been a little light sediment build up in the tank, maybe algae, but not enough to affect the pump. Now every spring I open the access port and pump it empty with a small transfer pump, rinse it out and its good for the summer.