Hi, As a guest, I read a thread somewhere on this forum that discussed pumps. Mostly, they had problems with the pumps when the faucets were open. So, I just joined hoping someone can offer advice. My problem with the Shurflo model 4008-101-A65 is that it cycles on and off every 1-3 seconds when the faucets are closed. There are no leaks as we have used the RV for a month. All faucets are pressurized and work perfectly when in use. I just drained the tank and lines, cleaned the inline filter and refilled the tank. Same problem. The RV is almost 2 years old and we did not have this problem until we took it out of storage a month ago. Any ideas would be greatly appreciated.
Shurflo pump cycles on/off
- Thread starter kenpt
- Start date
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Clay L
Well-known member
I know of two things other than a leak somewhere that can cause that.
There is a check valve in the pump that might be faulty. They don't cost much.
Also if the outdoor shower faucets are left on with the head turned off the small dribble can cause it.
There is a check valve in the pump that might be faulty. They don't cost much.
Also if the outdoor shower faucets are left on with the head turned off the small dribble can cause it.
denmarc
Well-known member
A system leak would be sure to show up if the pump is cycling every 1-3 seconds. Assuming the system is also water tight as mentioned, seems to me the pump still wouldn't cycle even if the check valve internally leaks and pressure setting is met and maintained..
Sounds to me that the pressure switch on the pump is faulty.
Sounds to me that the pressure switch on the pump is faulty.
Another clue is that after I turn off the pump, wait a while and turn it back on, it re-pressurizes itself for a few seconds and then continues the on/off cycle. Hopefully, I can do the repair myself, what ever it is, and save bunches of money! I believe I read somewhere there are repair kits for these pumps that may include the items mentioned by Clay L and denmarc.
RedandSilver
Well-known member
- Joined
- Aug 25, 2016
- Posts
- 1,325
I don't know if this will help - but you might contact the company. Do you have a service manual?
http://shurflo.com/rv-products/rv-pumps/rv-fresh-water-pumps/revolution-4008-pumps
http://shurflo.com/rv-products/rv-pumps/rv-fresh-water-pumps/revolution-4008-pumps
denmarc
Well-known member
I gotta ask...
Are you absolutely sure there are no leaks of any kind in the water system? Maybe a low point drain, pressure relief valve on the water heater, some drain valve that was turned and maybe not seated tightly when taken out of storage?
No drips at all under the RV?
Are you absolutely sure there are no leaks of any kind in the water system? Maybe a low point drain, pressure relief valve on the water heater, some drain valve that was turned and maybe not seated tightly when taken out of storage?
No drips at all under the RV?
Great Horned Owl
Well-known member
These o\pumps use s diaphragm to pust the water. If the rubber diaphragm stiffens up, watet can leak around them, and back into the tank. The kits to replace the diaphragms oa other seals, are not very expensive, and are fairly easy to install.
Joel
Joel
No leaks. We had it on the road for a month, using toilet, shower, hot/cold water. A leak inside would have been seen. I can actually see most of the line except under the shower floor. But, a leak there would eventually show up on the cabin floor. Also, I've checked underneath and have not seen any water there. The toilet is a wet bathroom with a foot pedal for the toilet. No running water there. The hot water tanks has been checked and no water from that compartment.
When we got home a few days ago, I drained the unit. Today, I put enough water into the tank to cover the pump line outlet and turned on the pump. I ran shower and kitchen faucet and flushed toilet to clear out air. I had the hot water tank bypass on. The pump pressurized and stopped running. A few seconds later, it started to cycle off/on again.
I don't have much of a manual, just a couple pages on installation and trouble shooting. Not much help to locate internal parts. I have contacted Shurflo about this but, no response yet.
Mr. Owl, I also wonder if some water was left in the pump over winter, froze and did some damage to the check valve, pressure switch or diaphragm? You know, the pump is almost level with the bottom of the tank. Can water seep back into the tank with 30 gallons of water on top?
Ken
When we got home a few days ago, I drained the unit. Today, I put enough water into the tank to cover the pump line outlet and turned on the pump. I ran shower and kitchen faucet and flushed toilet to clear out air. I had the hot water tank bypass on. The pump pressurized and stopped running. A few seconds later, it started to cycle off/on again.
I don't have much of a manual, just a couple pages on installation and trouble shooting. Not much help to locate internal parts. I have contacted Shurflo about this but, no response yet.
Mr. Owl, I also wonder if some water was left in the pump over winter, froze and did some damage to the check valve, pressure switch or diaphragm? You know, the pump is almost level with the bottom of the tank. Can water seep back into the tank with 30 gallons of water on top?
Ken
denmarc
Well-known member
kenpt said:
YEP!
denmarc
Well-known member
Just in case you're not comfortable with rebuilding your water pump, new pumps are not that expensive. I know yours is only approx. 2 YOA, but it happens.
Depending on your "handyman" expertise and/or time constraints, a direct replacement of the pump is not out of the question. Your call.
Depending on your "handyman" expertise and/or time constraints, a direct replacement of the pump is not out of the question. Your call.
Rene T
Site Team
kenpt said:
Sure can. The pressure will be around 35 to 40 Psi and will go right back into the tank if the check valve.
Another thing that would cause your problem is do you have a valve in the system that fills the fresh water tank while hooked up to city water? If you do and that valve is partially open, water will go right into the tank slowly and the pump will cycle on then off.
Thanks Mark. Yeh, I can get a new one at PPL for $79. While I was away from the forum, I got my nerve up and started to disassemble the pump. I took off the end cap and more, and exposed the diaphragm section. I check for blockage and dryness. All seemed good but, I had noticed that when I was unscrewing, one the the screws was loose. Perhaps the problem, leaking of air. I put it all back together, with no parts left over; whoosh. Filled up the tank, etc. No change, still cycling. I let it do that for some minutes while I looked at it. I gave it my "stop that" stare. Then I remembered I read about a pressure switch adjustment screw on the thread from 2015 about the water pump cycling while water was running. Well, I got a small Allen wrench, placed it in the screw and turned it 45 degrees to the left. More time was evident between surges. So, I turned it another 45 degrees and guess what? So far, no surging. And, I was just about to order a new pump. Maybe I should as $79 is a good deal. I've left the pump on and well periodically check on it. But, right now I feel good.
I want to thank all the contributors on this thread. It's great when you can get good advice and thoughts on problems. Thanks.
Ken
I want to thank all the contributors on this thread. It's great when you can get good advice and thoughts on problems. Thanks.
Ken
Attachments
muskoka guy
Well-known member
That is exactly what will happen if your city water valve is in the wrong position. Look in your water bay and make sure your valves are confirgured correctly. I had this happen to me as well. The pump kept cycling and there wasnt very much water pressure.Rene T said:
grashley
Well-known member
There are TWO types of leaks - external leaks (system losing water) and internal leaks (system moving water from pressurized area back into holding tank). I strongly suspect an internal leak.
The pump builds pressure and goes off. Water leaks backwards through the pump to the tank, pressure drops, pump comes back on.
Possible causes are the back pressure valve or possibly the pump itself. They are famous for loose screws holding the block together. Outer O rings keep the water in the system, but pressure pushes water backwards.
Always try the free fix first!
The pump builds pressure and goes off. Water leaks backwards through the pump to the tank, pressure drops, pump comes back on.
Possible causes are the back pressure valve or possibly the pump itself. They are famous for loose screws holding the block together. Outer O rings keep the water in the system, but pressure pushes water backwards.
Always try the free fix first!
denmarc
Well-known member
Congrats, kenpt! Sounds like you're on to a good thing. Keep us informed.
And yes the free fix should always be tried first. But sometimes one may not have the time or expertise to deal with it.
And then sometimes one just doesn't feel like messing with it. You just want to get it done and over with.
I feel that way once in while.
And yes the free fix should always be tried first. But sometimes one may not have the time or expertise to deal with it.
And then sometimes one just doesn't feel like messing with it. You just want to get it done and over with.
I feel that way once in while.
Thanks Mark. There really isn't much to the water pump diaphragm part. I hesitated working on it until I got courage from all who posted here. One just needs to be sure everrything goes back where it belongs. We will be taking off for a few day trip soon and will see how it goes. Ken
