Water Pump - open ended hose

[PeteK-Hou]

I have a ShurFlo 4008 water pump. I'm trying to diagnose the 'pulsing' of the pump. I understand it may just be an adjustment of the pressure switch. It doesn't pulse if I open the kitchen Unfortunately, the 'business end'of the pump was mounted towards the outside wall, make the adjustment screw non accessible unless I remove the pump (at which time I might as well replace the pump with a better unit).

But, my real question is there are 2 lines into the pump, one from the fresh water tank (valve in open position) one that has the valve closed and is open ended, no fitting or anything. Is this for adding antifreeze to the system for winterizing?

[doxiemom11]

Ours pulses if we leave the lever outside set for city water use but use the pump instead. If you set the lever for tank use - no pulsing. Could this be your issue?

[DancinCampers]

The procedure I found online and use to set By-pass and pressure switch. It requires having a pressure guage attached. I have a splice in my outdoor shower hose with a garden hose shutoff valve attached, to wash coach/car, to which I attach pressure guage.

You need to bypass pressure switch, directly powering the motor. With motor running, shower faucet open but not shower head, adjust bypass to 65 lbs on guage. Open and close shower head to make sure 65 lbs is stable, if not adjust bypass. After 65 lbs is stable, remove power to motor and put pressure switch back in circuit. Now adjust pressure switch to desired cutoff pressure (55 lbs is factory setting).

[ctilsie242]

I would also recommend adding an accumulator tank. The Shurflo 21 ounce tank is big enough to make a difference and reduce the "burrup" noises.

In fact, I'd probably recommend one of these tanks as a standard practice right after the water pump. I also have been thinking of having one on the hot water line after the water heater as well.

[Old-Biscuit]

PeteK-Hou wrote:

Old-Biscuit wrote:
S
And that pump: Per Shurflo Installation Instructions !!!
*Pump may be mounted in any position.
*Mount pump for easy access for cleaning strainer, maintenance and service

Seems RV MFG doesn't bother to read those :S

I don't have easy access to either. I'm going to try using a mirror to see adjusting screw. Anyone know what size allen wrench is needed? It may save my wife from hearing more #$@#$%^@ then necessary...

Thanks for this info.

5/64" Allen

HERE is a 'on the fly' adjustment method for both switches VS trying to set using a pressure gauge

[wa8yxm]

ScottG wrote:
Ugh. twisted sense of humor.

I often use two examples of what's wrong with several industries

The story is when the Model A or T (forget which came second) was being designed they brought Henry Ford a design for a Carburetor that had 14 Screws holding it together. he looked at and said "TOO MANY SCREWS".

So back to the drawing board. 2nd try had just 4 screws, same response

FInal design had only one and Ford was pleased.

Long about 1970 both Ford and GM relacing a heater core (done this)

Official instructions say drain cooling system.. No but do clamp the hoses. Remove hoses from heater core tubes, Remove about a dozen screws, Lift the lid, Lift the pad, Lift the core..

Drop in a new core, replace the pad, lid screws pre-fill core with antifreeze and re-attach hoses Remove clamps done,. (run engine to bring up to temp to check for leaks)

Today:
Evacuate air conditioner system,
Disconnect lines at firewall and seal off
Drain cooling system (Clamp hoses) disconnect at fire wall
Dissassemble Passenger side dash (Remove steering column on Renult)
Slide AC Evaporator out on its rails and remove heater core.


Theory: They have a contest to see how hard they can make it to service.


Punch line from a song "The Designer" (At least I think that is the tile, The Engineer is the other guess)

"Success at last I've designed a part that can't even be cast".

[ScottG]

wa8yxm wrote:
The open ended hose is for winterizing... You turn the valve and it sucks yucky pink stuff out of the jug.. I used air myself, saves on the pink yuck.

The pulsating you cite is normal.. For example. If I open my kitchen faucet on HOT.. the pump can pump more than the faucet can pass as the pressure increases it shuts off and decreases turns back on... (MIXED hot and cold does not do this)

The solution is not an adjustment it's a new variable speed pump.. or at least I think it is.. this is aq pump that speeds up or slows down as needed. to supply just ENOUGH water. Or so the ad suggests.

Not having one I can not be sure .

The variable speed pumps were a dismal failure because they had so many controler issues.
The newer pumps, like the OP's, run at full speed and have a bypass system for whatever volume isn't being used. They work good but not as nice as the old variable speed pumps - when they worked.
In a rare instance of luck, I have about the only 5.7 Sensor variable speed pump that works flawlessly.

[PeteK-Hou]

wa8yxm wrote:
The open ended hose is for winterizing... .

Not much need for winterizing here in Houston, although the last few days might say otherwise.

[wa8yxm]

The open ended hose is for winterizing... You turn the valve and it sucks yucky pink stuff out of the jug.. I used air myself, saves on the pink yuck.

The pulsating you cite is normal.. For example. If I open my kitchen faucet on HOT.. the pump can pump more than the faucet can pass as the pressure increases it shuts off and decreases turns back on... (MIXED hot and cold does not do this)

The solution is not an adjustment it's a new variable speed pump.. or at least I think it is.. this is aq pump that speeds up or slows down as needed. to supply just ENOUGH water. Or so the ad suggests.

Not having one I can not be sure .

[PeteK-Hou]

Old-Biscuit wrote:
S
And that pump: Per Shurflo Installation Instructions !!!
*Pump may be mounted in any position.
*Mount pump for easy access for cleaning strainer, maintenance and service

Seems RV MFG doesn't bother to read those :S

I don't have easy access to either. I'm going to try using a mirror to see adjusting screw. Anyone know what size allen wrench is needed? It may save my wife from hearing more #$@#$%^@ then necessary...

Thanks for this info.

[mobeewan]

The pump like he has (Shurflo 4008) is supposed to be able to work without need of an accumulator.

[old_guy]

put in an accumulator tank

[Old-Biscuit]

Shurflo 4008 has TWO adjustment screws..

One (in picture) is for the start/stop pressure switch.....S/B set for 55#

Other one (also in picture...lower left corner) is for the Bypass control.....S/B set to be fully open at 62# (which would be a low flow situation) ----starts to open at 40#

Bypass opens during 'low flow' demands so pump runs continuously vs start/stop/start/stop

Bypass is spring loaded diaphragm.
Counterclockwise on adjustment screw---lowers pressure that bypass opens at

But if either switch is adjusted too much .....they can overlap and pump will NOT shut off
Remember..pressure switch stop pressure has to be LOWER then Bypass full open setting


And that pump: Per Shurflo Installation Instructions !!!
*Pump may be mounted in any position.
*Mount pump for easy access for cleaning strainer, maintenance and service

Seems RV MFG doesn't bother to read those :S

[ScottG]

Ugh.
Some of those assembly folks really have a twisted sense of humor.

[PeteK-Hou]

ScottG wrote:
Here's your pump (sorry, I swiped it while you were in the shower) :B
The allen screw I'm pointing at will adjust out the pulsing. Just give it a bit of turn in either direction and see what happens.
This pump works flawlessly!



Cheers,
Scott

Thanks..I wondered why the water pressure went down.. 🙂
The pump was installed with the end the has that set screw towards the outside wall. Without taking the pump out, I'd have one hell of a time feeling my way in to getting an allen wrench in there.

Thanks