Water pump slows to a trickle

[SlowBro]

My water pump is pressurizing very slowly; Aside from the pump strainer, what else can I check?

I filled the fresh tank to do the bleach sterilization and draining it through the faucets took hours. (In fact, if the fresh gauge can be trusted, there is still some water in the tank.) If I have all of the faucets off and turn on the pump, I can hear it bring the system up to pressure, and that takes about 30 seconds. Then if I open a faucet I get a nice blast of water for about 10 seconds and then it slows to a trickle. The pump runs while putting out that trickle. It doesn't matter which faucet I use, bath sink or shower or kitchen, they all do the same.

The pump sounds fine; I don't have a lot of real RV experience so I'm mentally comparing it to my grandparent's Class C 25 years ago and it sounds fine. The mechanic, who seems to be trustworthy, briefly checked the pressure last week with a few gallons in the tank. I asked if he ran it long and he said no. He might not have had it on long enough to give it a good test.

I saw no valve handles underneath such as a city/fresh valve, nor is there any such reference in the manual.

Aside from the pump strainer, what else should I look at?

[SlowBro]

Put through a second tank of water and now it's running beautifully. Thanks all!

[SlowBro]

We usually don't winterize, although this year we had a few close calls. I don't think this rig has a valve for antifreeze. Didn't see anything in person or the manual. I think though there is lots of air, but not sure if that's because I am turning off the pump and leaving the faucets open? I plan to test GPM tomorrow.

[hawkeye-08]

Just had a similar problem when dewinterizing. I did not purge the outside shower because we are still getting temps in the mid 20s or lower at night some and I wanted to leave the antifreeze in the lines. My pump worked fine purging lines until I opened the line to the water heater. It took more time than expected, but then after the water heater was full, I could not get decent flow... I ended up purging the outside shower lines and once all the air was out, the system pressurized fine and has proper flow.

Do you have all the air purged from the system? Is your valve for putting in antifreeze completely switched over to the fresh water tank?

[schlep1967]

Question for you. When you winterize do you have a suction tube that you use to draw antifreeze straight out of the jug? If this is the case the valve you use to select where you draw fluid from may be in the wrong position allowing you to draw air in from one side and water from the tank. For some reason mine has a 3 position valve on it. One position draws from the tank, one draws from the suction tube, and the 3rd one draws from both. If in the 3rd position with all faucets closed it will eventually draw enough water to build pressure and shut off the pump. But once there is a demand for water the pump can not keep up due to the air being added to the equation.

[SlowBro]

Maybe I should try to fill a gallon jug from the faucet to know the GPM then compare that to the pump's rating?

[SlowBro]

The pump strainer was very clogged and now is clear. However, the flow is not what I would consider very strong. For example, water does flow from all of the holes in the shower head but without much pressure, it just sort of "falls" out of the head.

Dr Quick, yes both hot & cold, all faucets. How easy or difficult is it to take off the suction line?

[Dr_Quick]

To me it sounds like you have a flow restriction somewhere. Is it the same for both hot and cold water? If so probably something in the line between pump and where it 'T's off to line to hot water heater. Also possible problem with suction line from tank, some thing in line or either obstruction at exit from tank. You might be able to take suction line off tank and look into fitting. Also try a hose from a gallon jug of water to pump and see what happens, that will tell you if it is before or after pump.


RESPONSE to post below.
On my trailer it is just a "hose line" that goes between the pump and the water tank. It has screw type clamps on the line. As long as it is accessible it should not be to hard.

[Teacher_s_Pet]

Had a slow faucet at one of our rentals 8 or 9 years ago, very low flow at faucet then again at the shut off. Saw something white at shut off exit ....started pulling on it, almost 2.5 feet of Teflon tape in the water line. Only answer was recently we'd had a new well put in. Must have come from that, maybe a worker had dropped it down the casing.

[SlowBro]

I've heard of two S&B having major damage from ice maker supply. Nothing to sneeze at. I'd want braided steel lines if we ever install that.

No there are no leaks, just very slow flow. About to look at the strainer, then if I find nothing am taking it to a mechanic.

[Teacher_s_Pet]

30 seconds seems like a long time to pressurize the system. Does it stay pressurized or does the pump cycle intermittently? If the pump comes on say in 10 minutes look for a leak after the pump or check the fresh water fill for a faulty check valve. In over 37 years of Rving in 8 different Rvs we have had:

• A cracked pump strainer
• Cracked lines
• Fitting leaks
• Bad pump diaphragms
• A name brand faucet leaking from the brass body at line inlets (last year)
• Water pump leaking through the back of the pump motor (new coach, 2 months since delivery)
• Bad fill check valves (3 times)
• Bad water heater check valve (a first this winter)
• Bad water heater by-pass valve
• Bad water heater pressure relief valve (2 times)
• Leaking water heater tank
• Debris in faucet strainers
• Going way back, a bad air compressor head gasket on a pressurized system with a metal fresh water tank

Any can cause water problems at the faucet, just start at the fill and work toward each faucet or valve. I have heard of loosing water through the ice maker supply lines, still waiting for that one to happen.

[SlowBro]

Nice, thanks. I intend on looking in the morning.

[nvlaircrew]

Check the bowl the strainer sits in. I had a similar problem with mine. Couldn't get pressure with any sink valve open and took a long time charging to pressure. The bowl turned out to be cracked and it was sucking air into the lines instead of water from the tank. I took the strainer out a couple times thinking I had sediment clogging it up. I sometimes fill from a creek while dry camping for extended periods. Finally noticed the crack at the bottom of the bowl while wiping it out. Glued it back together with some JB Weld and not had another problem. Just got to remember to take the bowl off while winterizing. i figure the crack was from water freezing.