Water pump fails to totally cut off on battery

Outsider · 09-11-2019, 08:18 PM

I posted this on the Tech - Plumbing section but did not get a single response. Any of you Boondockers heard of an issue like this?

Water pump fails to totally cut off on battery
2015 Coachman Clipper 16B.
When dry camping and on battery only, by the 2nd day the water pump begins to randomly not cut off fully. It appears to run until it reaches nearly full pressure, begins to slow down and then stalls in a high current draw position without cutting off. I have a plug-in digital voltage monitor plugged into the 12VDC adapter port and can watch the voltage go quickly down from 12.35 volts and hang at about 11.85 volts in a RED under-voltage condition. I turn the faucet OFF and then manually turn the wall mounted pump switch OFF and the voltage immediately jumps back up to 12.34 or so. The pump will then stay OFF until I run more water and the pressure drops and calls for more water pressure again.

Is this a common problem with the WFCO PD130-1240E pump (according to the mfg installed utilities list that is what I have)?

Is there a pressure adjustment or does a solenoid need a squirt of WD40? It works fine when we have AC hookups instead of battery only.

Thanks for your insight.

Scrapper · 09-11-2019, 09:30 PM

Never heard of a WFCO PD130-1240E water pump. Most rv water pumps are either Flojet or Shurflo.

Theo · 09-12-2019, 08:08 AM

This is the OP's water pump, I believe:

WFCO Water Pump

IIRC, there is an internal pressure sensor in the pump that stops it from running when the proper PSI exists. Perhaps the sensor has failed or was not "calibrated" correctly.

You may want to research whether the sensor is adjustable.

**Flybob** · 09-12-2019, 08:33 AM

Check your battery. It is possible the battery is starting to go bad ( 4+ yrs old if original) and that after running for a short time the battery voltage is too low for the pump to fully pressurize the system to trigger the cut-off. If you can, try it connected to shore power or a generator. it would be interesting to see if you still have this issue. As you can see from the attached chart, the running voltage you are seeing is pretty low.

Larry-NC · 09-12-2019, 01:11 PM

Quote:

Originally Posted by Flybob

Check your battery. It is possible the battery is starting to go bad ( 4+ yrs old if original) and that after running for a short time the battery voltage is too low for the pump to fully pressurize the system to trigger the cut-off. If you can, try it connected to shore power or a generator. it would be interesting to see if you still have this issue. As you can see from the attached chart, the running voltage you are seeing is pretty low.

Or you could simply run jumper cables from your car/truck battery to the trailer battery. If the problem persists, it is likely that the pump pressure switch is failing to cut the motor off. It looks like you could replace the switch by taking the black cover off the end of the pump.

Or as another means of diagnosis, you could take the end cover off and use your multimeter to see whether the switch ever opens. Set it on the 20v range and put the leads across the switch terminals. It will read 0v while closed (pumping) and 12v open (pump cut off).

MtBiker · 09-12-2019, 01:56 PM

Maybe check the filter to be sure it is clear. To me it sounds as if it is loading up, maybe having a hard time sucking water. A kink in a line or your system is building up vacuum.
Just my thoughts.

TheWolfPaq82 · 09-12-2019, 02:11 PM

Quote:

Originally Posted by Flybob

Check your battery. It is possible the battery is starting to go bad ( 4+ yrs old if original) and that after running for a short time the battery voltage is too low for the pump to fully pressurize the system to trigger the cut-off. If you can, try it connected to shore power or a generator. it would be interesting to see if you still have this issue. As you can see from the attached chart, the running voltage you are seeing is pretty low.

Quote from OP. "Is there a pressure adjustment or does a solenoid need a squirt of WD40? It works fine when we have AC hookups instead of battery only."

D W · 09-12-2019, 03:28 PM

Quote:

Originally Posted by TheWolfPaq82

Quote from OP.It works fine when we have AC hookups instead of battery only."

↑ THIS ↑ If it runs fine under converter power there is nothing wrong with the pump. Start checking your battery (s), and connections.

Iwannacamp · 09-12-2019, 03:59 PM

I purchased an electronic battery tester on Amazon... kinda like the ones that used to cost a $1000. I think I paid about $30 for it. Seems to work fine. I know. I know. Any place will check your battery, but with 3 cars, 2 lawn mowers and an RV plus kids it will be handy+++ you can do it at home.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Outsider · 09-12-2019, 07:09 PM

Thanks for the input. Yes, it appears to be the internal pump pressure switch hanging in some way, battery, or the pump is just drawing more current than it should. As a reminder, it works good the 1st day of boondocking but then gradually gets worse over the next day or two. (I do not have solar nor a genny yet. Adding solar soon.)

Battery is only one year old but it is a simple marine deep-cycle (trolling motor type). The electrolyte in the cells looks consistent across all 6 cells at about 3.5 floating balls.

I'll do some more testing this weekend.

campers302 · 09-13-2019, 09:11 AM

Quote:

Originally Posted by Outsider

Thanks for the input. Yes, it appears to be the internal pump pressure switch hanging in some way, battery, or the pump is just drawing more current than it should. As a reminder, it works good the 1st day of boondocking but then gradually gets worse over the next day or two. (I do not have solar nor a genny yet. Adding solar soon.)

Battery is only one year old but it is a simple marine deep-cycle (trolling motor type). The electrolyte in the cells looks consistent across all 6 cells at about 3.5 floating balls.

I'll do some more testing this weekend.

So it is now September. What did you find? What was the result of your testing?

TheWolfPaq82 · 09-13-2019, 09:46 AM

Quote:

Originally Posted by campers302

So it is now September. What did you find? What was the result of your testing?

The OP posted two days ago that he'd be doing more testing this weekend. That was Sept 11th. ????

campers302 · 09-13-2019, 10:07 AM

Quote:

Originally Posted by TheWolfPaq82

The OP posted two days ago that he'd be doing more testing this weekend. That was Sept 11th. ????

I was looking to the left of the post and saw my join date and thought it was his post date.

Thanks

Outsider · 09-20-2019, 08:03 PM

There is no room around this water pump at all. Very cramped quarters. I had hoped to try adjusting the allen screw in the head of the pump but cannot get to it at all. Looks like I will have to completely remove the pump. (Not sure it is worth the time investment at this point.)

Anyone have an easy way to remove pressed on hose clamps on the hoses that get put on at the factory?

TitanMike · 09-21-2019, 11:08 AM

A lot of water pumps today are "bypass type". They have two adjustments, one that puts it in bypass mode and the other to totally shut down the pump at max pressure.

Before turning any screws make sure to get a copy of the pump manufacturer's instruction manual and follow the procedures for adjusting each.

FWIW, if a pump isn't receiving enough power (voltage drop in electrical supply) to reach shut off pressure it could operate just as you describe. The fact that it works fine when on shore power and converter is supplying power is to me a dead giveaway that the issue is power related, not pump adjustments.

Could be as simple as a loose connection along the line or a battery that is not providing sufficient voltage under load.

rockfordroo · 09-21-2019, 11:14 AM

Quote:

Originally Posted by TitanMike

A lot of water pumps today are "bypass type". They have two adjustments, one that puts it in bypass mode and the other to totally shut down the pump at max pressure.

Before turning any screws make sure to get a copy of the pump manufacturer's instruction manual and follow the procedures for adjusting each.

FWIW, if a pump isn't receiving enough power (voltage drop in electrical supply) to reach shut off pressure it could operate just as you describe. The fact that it works fine when on shore power and converter is supplying power is to me a dead giveaway that the issue is power related, not pump adjustments.

Could be as simple as a loose connection along the line or a battery that is not providing sufficient voltage under load.

X2

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