I recently installed a new ShurFlo 4008 on my coach. It states that it has variable flow capabilities allowing its use without the accumulator tank so I installed it that way and threw away the 18 year old accumulator. The big problem is that it would cycle about every 20 minutes with everything shut off. I have thoroughly checked for water leaks and cannot find any so I'm presuming the back flow check valve is leaking. One reason I put the new pump in was that the old pump, a ShurFlo 2088 purchased in 2010, also cycled when there was no water being used. I presumed the same thing that the back flow check valve had a leak. I guess its possible that both pumps were faulty but I'm wondering if anyone out there has another idea. In my mind if there is a system leak causing the problem, there should be water leaking somewhere.
One additional thought, I really did not like the pulsing of the 4088 when using the kitchen counter top water filter or when the faucet was not turned on wide open. I have since put a new accumulator tank in. I like the functionality of the system with an accumulator much better. Oh, and I don't think the 4088 produces as much water pressure as did the 2088.
It sure sounds like a leak to me, but may be an internal leak like the water fill valve to fill the tank which would be hard to detect as it is just returning a small amount of water from the pump to the tank, just a guess
We installed a SureFlo SmartSensor 4.0 when we purchased the coach. Foretravel does not sell this unit, but had one shipped from the factory. No issues. We did this after we tried two other Sure Flow units that we were not satisfied with. FWIW
Extreme™ Series Smart Sensor™ - SHURflo (http://www.shurflo.com/rv-products/rv-pumps/extreme-series-water-pumps/extreme-series-smart-sensor/default.html)
I have been pleased with the performance of the Aquajet ES. I left the accumulator in the system and adjusted the pressure in the accumulator to be suitable for the Aquajet ES. I've been snugging a few fittings on the soft loops to stop some small leaks, but haven't had any leak down issues.
The Aquajet ES is a direct replacement for the OEM pump and required no wiring changes. The Aquajet RV is a bit stronger, but would have required larger gauge wiring.
Red Tractor's suggestion of a leak at the fill valve may be a good call. I just ran a little test by opening the manual fill valve under the bathroom sink. Opening the valve set up a loop that allows the pump to try to fill the fresh water tank with water from the fresh water tank. A small leak there would cause the symptoms you describe.
Boy am I glad we have this Forum. I never thought of a minor leak in the fill valve. I'm betting that is the problem otherwise I should see water somewhere. Thanks Red Tractor, a Kudo for you.
At least on ours, the fill valve is in the wet bay. You would definitely know if that were leaking.
I believe I have determined that the problem is the water fill valve. We have a hose reel and with the system pressurized there is a small amount of water that exits the hose. If I understand correctly, if the fill valve is shut off completely, there should be no back flow out of the hose.
Problem Solved. Thanks!!!
Not sure of the 93's, but if you have a check valve in the freshwater fill line (I'm pretty sure you should) and it's not sealing you should not have any backflow out the shore hose. The check valve should be between the connection to shore water and the fill valve.
That's how we discovered our check valve had failed - water exiting the shore hose when the water pump was on. And that was after we replaced the fill valve which was also leaking through and causing the pump to run for a few seconds without any water demand (your other symptom).
Worth checking into (no pun intended)
Michelle
Kent,
Running the pump without a tank sounds good. Are there still pulses when it comes on? How loud is it?
Our valve is under the bathroom sink and if cracked open a little, the pump will run.
Anyone think about a leaking valve pushing water back out the shore hose connection in the wet bay and then migrating into the space where the plywood, foam and rectangular tubing are located? A small amount but the constant moist condition might cause trouble. Ours had been leaking when we bought it.
Pierce
On our 1997, there is a 1/4 turn ball valve on the floor of a cabinet under the bathroom sink. The valve normally remains closed. When it is open, it allows water from the pressurized water system to flow into the fresh water storage tank. The water can leak through the valve and discharge water into the fresh water tank. You could loose pressure by returning fresh water to the fresh water storage tank. A leak through that valve should not cause water to exit through the fill connection.
You could also be loosing pressure through the check valve on the shore water inlet. A leak in that valve could cause water to exit through the shore hose. You could check for that possibility by attaching a short (washing machine) hose to the inlet, routing it to the ground, and checking for leakage while operating with "on board" water.
Michelle described the experiences of leaks at both places. Symptoms are similar.
If you will pay for our fuel, Marilyn and I could drive to your location and do a personal inspection. :P