Water pump surges?

[SilverGhost]

I have been looking around, doing a lot of reading. Great stuff on here, I now have a couple page list of stuff I want to do

The few times we have boon docked and used the electric water pump it has pulsed badly. The pump cycles on and off about as fast as turn signals on a car flash. Makes me wish I could adjust the pressure switch a little, but I believe ours is a simple, sealed unit.

Now which would you do? I have a couple ideas on making the system deliver a smoother water flow;

1) Install a different water pressure switch. Either adjustable or just higher pressure to limit the amount of pump cycling.

2) Install a pressure bladder similar to the tanks used on homes with wells. Small tank absorbs the pressure and helps keep a more consistent pressure.

3) Combination of both?

Jason

PS; would a pressure limit valve that dumps back to the tank be viable?

[Peter Steckhan]

Believe it or not, RV-specific accumulator tanks are available. They're smaller than what you would have for your house:

Water System Accessories - SHURflo

My pump with built in pressure switch pulses if I've got the faucet barely open, but it's smooth if the faucet is all the way open. I'm thinking of getting an accumulator tank so slower flows are smooth too.

[Terry G]

Jason, here are some possibilities:
1) My pump tends to cycle on and off like you describe if I open a faucet only a little bit but keeps running if I'm using more water. As far as I know, this is normal and not a problem.
2) The water pump can act strange if there's air in the lines. I've been able to fix this by opening all the faucets at the same time until water flows smoothly.
3) Could there be some sort of restriction in either the inflow or outflow of the pump?

Water pumps are fairly inexpensive but usually operate fine without the other gadgets you mention.

[Thomas G.]

Plus 1 on the accumulator tank. I made my own from 1 1/2" PVC pipe capped on the end and mounted vertically. Not as neat as a bladder type, but cheap.

[peterh]

Tom's solution is cheap and simple. The tricks to making it work that he didn't mention are:

* You need to have a capped vertical length of large-diameter (in Tom's case 1-1/2") PVC pipe with connected to a 1/2" "T" with transition connector-adapters. (Me? I'd use 6-10" of 2" diameter pipe.)
* The supply line needs to be horizontal.
* The air bubble at the top of your float will slowly get absorbed into your water supply over time. For this reason it's a good idea to occasionally -- like during your annual trailer clean-out -- completely drain your water supply system completely and air out. It can be handy to have a valve on the top of the float cap to make this easier to do.

[Ron in BC]

Plus 3 on having a tank

I've used home made ones with good success. The best one I made was from an old s/s fire extingisher, the kind that you invert to use. It was also mounted higher than the faucet. It, in effect, became a "day tank" and once pumped up would provide water without the annoying rapid cycling of the waterpump for a long time.

I've also used a small, non-bladder tank and they also work well enough for me. My criteria is that I'd like to be able to rinse my hands etc. without the pump cycling on and off. Some people don't seem to mind it but it drives me nuts

Ron

[Frederick L. Simson]

Originally Posted by Ron in BC

Plus 3 on having a tank

+4 for the accumulator tank.

My biggest problem now is seepage from the "City Water" connector when we boondock using the fresh tank and pump. When I hear the pump cycle, I go out and check; usually finding a puddle under the fitting. The cap on it has to be snug as the valve never seems to seat properly. I've changed this fitting once, maybe it's time to do it again.

[SilverGhost]

Sounds like surge tank, it is. I have seen the ones at Home Depot that are for "hammering" - my house has a small one above the water heater in the garage. It is a small blue tank, about the size of a gallon of milk, and works like the bigger tank for the well. They also have the smaller copper "anti-hammer" pipes.

Mine is worse. Even with both hot and cold open full the pump cycles. I think this is the one time Jim's motto of overbuilding everything may have not been the best idea. A smaller pump or a higher pressure switch would have made an improvement.

Thanks for the great replies, now I just need to get around to it.

Jason

[steve dunham]

Well pressure switches have two settings . Range and Differential .Range is the top end pressure where the pump turns on (40-50-60 Lbs and differential is the difference between cut in and cut out pressure I.E 40-20 , 50-30 , 60- 40(20 lbs differential) Differential and a pressure tank helps prevent short cycling of the pump and overheating of the pump motor. Since trailer systems usually have no system to store water under pressure the differential portion of the pressure switch is basically useless. Tom is correct you need some form of pressure tank or accumulator to help control your cycling at low flow.
The 2 '' pipe Peter described is still used in my area but with city water to control water hammer . A 2" x 6 ft.Pipe is placed at the waters entrance to the bldg

[Frederick L. Simson]

Originally Posted by Frederick L. Simson

+4 for the accumulator tank.

A picture of my pump and tank installation. shurflo-accumulator-tank

[SilverGhost]

Originally Posted by Frederick L. Simson

A picture of my pump and tank installation. shurflo-accumulator-tank

Nice setup! I'll see what the price of the Home Depot tank is and how hard it would be to plumb up then check on the Shur Flo setup. Jim assembles the new Eggs with syn-flex hose and fittings, so I have to find a source for those.

Jason

[Carol H]

Frederick when you figure out which City Water Connection is the best one that doesnt leak on and off please post!! I am on my third one .. all have been different brand/style and I still have from time to time a leak from the fitting that cant be stopped no matter what. I did find though that buying a new hose helped more than replacing the fitting the last time though. Not sure if the threads on the hose wear down over time or what.

[Lloyd (aka Santa) Coltman]

Have any of you looked this site RV Mods, RV Modifications, RV Upgrades, RV Tips, RV eBooks | ModMyRV.com ? There is a complete write-up (under plumbing) on how to home-build and plumb in an accumulator tank, and lots of other really interesting modifications. You'll see some my comments as Lloyd BC on that site.

[Lloyd (aka Santa) Coltman]

Originally Posted by Carol H

Frederick when you figure out which City Water Connection is the best one that doesnt leak on and off please post!! I am on my third one .. all have been different brand/style and I still have from time to time a leak from the fitting that cant be stopped no matter what. I did find though that buying a new hose helped more than replacing the fitting the last time though. Not sure if the threads on the hose wear down over time or what.

Are you saying the internal check valve on the city water connection is leaking back? I've had trailers that were 30+ years old, and not had that problem, although our niece has had it with their unit (only 7 years old). Are you using a strainer screen equipped hose washer (Camco #20183), similar to what's used on an automatic washer? The only reason I can think of, for the valve to leak, is foreign material getting lodged in the valve, from a supply hose or hose bib. Our current unit (2011 Sportsmen) came equipped with this type of washer from the Mfr., don't know about others. As a matter of fact, I use one as an input strainer, at the input end of my suction hose (a 5' washing machine supply hose) when drawing water from the river to refill our fresh water tank when 'Boondocking'. That way, I avoid problems with the valves on my transfer pump (a second-hand Flojet 'Quiet Quad' that gets used by three or four of us, from time to time).
If washing machine valves need the protection, why wouldn't your city water connection?
BTW, our water pressure regulator also came equipped with a screen/hose washer, and I wouldn't use any other type.