Shurflow Water Pump Issue

Hey guys - I've got a Shurflow 4008-101-A65 water pump that's only a couple months old and acting up. It pulses on/off for a split second every five seconds or so. I've ruled out a slow leak as it does this even while filling up the fresh water tank. Has any else experienced this issue or have any idea what might be causing it??

TIA

1704x4 said:

Hey guys - I've got a Shurflow 4008-101-A65 water pump that's only a couple months old and acting up. It pulses on/off for a split second every five seconds or so. I've ruled out a slow leak as it does this even while filling up the fresh water tank. Has any else experienced this issue or have any idea what might be causing it??

TIA

Click to expand...

You can get a pressure gizmo that 'normalizes' the pressure using a diaphragm. Might be worth adding one on?
Mine pulses every so often (not 5 minutes though) and reminds me to turn the power off when not using it.

1704x4 said:

Hey guys - I've got a Shurflow 4008-101-A65 water pump that's only a couple months old and acting up. It pulses on/off for a split second every five seconds or so. I've ruled out a slow leak as it does this even while filling up the fresh water tank. Has any else experienced this issue or have any idea what might be causing it??

TIA

Click to expand...

The slow leak that would or may make it pulse is not on the source side, but the supply side. Check your faucets for a slow pressure release.

OrioN said:

The slow leak that would or may make it pulse is not on the source side, but the supply side. Check your faucets for a slow pressure release.

Click to expand...

I have a Flo Jet pump that made a short pulse every few seconds. I thought it was a leak on the supply side, but it stopped when I cleaned the input strainer.

Don't know why that fixed it.

A sticky or bad check valve in the pump can cause it to leak water back to the supply side, and thus pulse every few seconds.

Do you have an intake strainer? Without one the pump can ingest debris which can cause the valve to hang up. There are videos on repairing the unit.

The 4008 also has a bypass valve to allow for smooth operation. If the bypass valve is sticking or not adjusted properly, you can get odd cycling. You can adjust this valve using a 5/64 allen wrench. Take note of any adjustment you make, as you may need to revert for proper operation. There are two adjustment screws on the pump head. The one near the wires is the cut-out pressure switch. The other is the bypass valve.

http://www.doityourselfrv.com/adjusting-pressure-switch-on-shurflo-water-pump/

You guys are awesome - thanks for all the help. Does anyone have any recommendations for a company/person that could help me out with this? We are driving east and will be in driving north to south (Maine, Boston, New York, etc).

Thanks again

1704x4 said:

You guys are awesome - thanks for all the help. Does anyone have any recommendations for a company/person that could help me out with this? We are driving east and will be in driving north to south (Maine, Boston, New York, etc).

Thanks again

Click to expand...

Oh Shoot! A conversion....

Well, if you know where the pump is, usually the strainer is a clear plastic bowl on the intake side of the pump. Clear plastic unscrews to clean the screen.

I think the pump is telling you that you (despite checking things) have a very small leak on the pressure side. Although, it is possible that with a low fresh water tank it could be gulping some air or even a suction leak on the intake side. I'd look at the O-rings on the threaded couplings and the filter cap for sure.

These pumps use several reed valves (like a heart valve) run on a wobble shaft. They have to close completely to develop pressure and avoid bleed back (regurgitation) and loss of pressure. That will also make the pump switch on and off as the pressure bleeds off.

I've had a pump get FODDED twice and stop pumping or have low pressure due to eeny-weenie bits of plastic from the water tank getting through the screen. They jam in valve seat and hold it open just enough to cause problems. You can if you are 'crafty' remove the pump head (3 screws) and carefully open it up. Take pictures!!! Once open you can see the diaphragm and the three reed valves and wipe them clean (carefully). You may have to take the pump out where you can see what you are doing.

Before doing that, I'd really take a close look at all the pipes and fittings on the pressure side to be absolutely sure you are not leaking.

Update: Using the tiny Allen screw on the cap where the 2 wires connect (cut-out pressure switch). I adjusted it counterclockwise until the pulsing on/off reduced down to every 5 minutes or so. Problem is that now the water flow is constricted....maybe a tiny pressure leak at the faucet?? Perhaps I should try adjusting the other Allen screw as well?

Thanks everyone for your help! - especially midwestdrifter for the youtube video.

Mike

You just adjusted the water pressure down, so obviously the flow will be reduced. I would adjust the pressure back to where it was. You can try increasing the bypass pressure, just make sure you don't get rapid cycling when the faucet is cracked open slightly.

as mentioned, you probably have a bad, check valve in the pump head, or some debris has gotten stuck in the valve.