Help! Shurflo pump won't pump

[beardrum]

Hi,
Once again, I turn to this forum as a problem solving resource. My 2014 Scamp 16' with a forward bath has a Shurflo transfer pump to move shower and sink water to the back of the trailer where the grey water tank is mounted. (I'll hold my grumbles about that design for a later time.)
When the sink is full, or the shower is running, the user switches on the pump to move the waste water back. We're on the road, and have been using the pump normally until yesterday, when it suddenly stopped transferring water. It runs, so I cleaned the filter, and took the pump apart and cleaned it out, finding a possible stuck check valve, but on reassembly, it still doesn't transfer water. All connections seem tight, but putting fresh pipe thread tape on ALL the connections is my next shot.

Any other ideas? I'm a little surprised to have it fail so suddenly in the middle of a trip.

As always, thanks so much!

Chuck

[Raspy]

Sounds like a clog before the pump, or a stuck check valve, if there is one, after the pump.

With a water hose, try blowing out the line backward toward the shower/sink. Then try blowing out the line between the pump and the tank. You don't need special fitting for this, and it might spray some water around as you do it, but just hold the hose to the pipe and have someone turn the water on a for a few seconds. Tape up the connection or wrap it with a rag if needed. It won't take much pressure.

You already cleaned the filter and the pump, so those can't be the problem.

Is that a diaphragm, or centrifugal pump? If centrifugal, you can flush it out too, with your hose.

[floyd]

The filter protects the pump, but it also can act as a dam for hair and debris.
remove the line on the upstream side of screen filter and snake the line with a bent wire or reach in with a pair of needle nose pliers to clear the line.
There is no check valve.
Also...
The bathroom sink and the shower drain work better if only one is open at a time.
The typical Shurflo pump is a sort of wobble piston design which could jam if a solid object gets in.
You could test it by putting the inlet line into a gallon jug of water then switch it on.
While the line is off, drain a sink full of water and see if it runs out of the filter.

[beardrum]

Thank you for your responses.

I like the idea of testing the pump by sticking the inlet line into a bucket of water. I'm pretty sure it will show the pump has no suction. It's really weird, because it was working one minute and then not the next.

The lines are clear; I get a stream of water from the sink/shower lines right at the pump, downstream of the filter. I did have to clean a ton of crud out of the filter.

I think there is a bit of a check valve integral to the pump head. When I had the pump on the table, I pulled the head off and found that a little spring-loaded diaphragm was stuck. I freed that up by rinsing it in clean water. But on reassembly and re-installation, no joy. I'm also pretty sure the lines are all airtight now, I juried up some pipe dope on all the hose clamp fittings and tightened them up.

Zeroing in on a failed pump. I'll see if I can find some fittings to try to bucket of water test.

Thanks again.

Chuck

[redbarron55]

Check the pump by plumbing to a pail of water to see if it will pump.
One thing people often forget is a leak on the inlet side that lets air into the pump will also shut down the pumping as it would rather pump air than water.

[kdhanso]

Originally Posted by beardrum

Thank you for your responses.



I like the idea of testing the pump by sticking the inlet line into a bucket of water. I'm pretty sure it will show the pump has no suction. It's really weird, because it was working one minute and then not the next.



The lines are clear; I get a stream of water from the sink/shower lines right at the pump, downstream of the filter. I did have to clean a ton of crud out of the filter.



I think there is a bit of a check valve integral to the pump head. When I had the pump on the table, I pulled the head off and found that a little spring-loaded diaphragm was stuck. I freed that up by rinsing it in clean water. But on reassembly and re-installation, no joy. I'm also pretty sure the lines are all airtight now, I juried up some pipe dope on all the hose clamp fittings and tightened them up.



Zeroing in on a failed pump. I'll see if I can find some fittings to try to bucket of water test.



Thanks again.



Chuck

The thing I think you describe as a check valve is the sensor used to detect pressure when this pump is used for freshwater. It turns off when enough pressure is built up in the lines. However, it’s not really needed for the grey water. My pump developed some scale buildup around this switch and quit working leaving the switch in the off position. I cleaned out the scale and the pump started working again.