Water pump cycles on and off?

We just got back from a week plus and our pump did the same thing- at very low flow rates (barely turned faucet on), and it ran continuously when open further.

When trying to conserve battery and reduce all sound, constantly on and off does not meet our goal. Great flow, though.

We'll be adding an accumulator and replacing some hard lines with flexible and insulating some vibration points.

In our experience, an accumulator is good for a few flushes as well when the pump is off. Imagine coming back from being out all day and having the pump off while you're gone, and sneaking into the bathroom and either having to go switch on the water to flush, or if just washing hands, walking through camper with soapy hands, LOL.

Well worth it, IMHO ;)

doxiemom11 wrote:
While you were working on the pump, did you have your water set up to use from the city water connection. If so, did you remember to change it back for tank and pump use? Our pump does that if we have not changed our handle back to what we are using.

Our trailer doesn't have this feature. I'm going to try the adjustment settings when I'm back home and have my Allen wrenches.

While you were working on the pump, did you have your water set up to use from the city water connection. If so, did you remember to change it back for tank and pump use? Our pump does that if we have not changed our handle back to what we are using.

acritzer wrote:

georgelesley wrote:

Old-Biscuit wrote:
Your Shurflo 4008 has TWO adjustments. \\\

One is for pressure switch....
One is for Bypass control

Bypass allows water to return suction side during low water demands

IF you do not adjust CORRECTLY then pressure adjustment and Bypass adjustment can overlap and cause pump to NOT shut down.


HERE is an off-the-cuff adjustment method

Ours did the same thing until this adjustment was done now runs smoothly w/o cycling.

So did you do the entire "reset" adjustment listed in the link?

Yes. Might take a few tries to get it exactly right

New pump last year and it cycled too much also. We called Sureflo and they told us to turn the adjustment screw. Can't remember how many turns but it did fix the problem

georgelesley wrote:

Old-Biscuit wrote:
Your Shurflo 4008 has TWO adjustments. \\\

One is for pressure switch....
One is for Bypass control

Bypass allows water to return suction side during low water demands

IF you do not adjust CORRECTLY then pressure adjustment and Bypass adjustment can overlap and cause pump to NOT shut down.


HERE is an off-the-cuff adjustment method

Ours did the same thing until this adjustment was done now runs smoothly w/o cycling.

So did you do the entire "reset" adjustment listed in the link?

acritzer wrote:
People saying it's working correctly....I have read in the manual that cycling is bad and shortens the life of the pump?

That is ONLY if it is cycling continuously when it should NOT BE.

It MUST cycle on and off in order to work correctly.

Old-Biscuit wrote:
Your Shurflo 4008 has TWO adjustments. \\\

One is for pressure switch....
One is for Bypass control

Bypass allows water to return suction side during low water demands

IF you do not adjust CORRECTLY then pressure adjustment and Bypass adjustment can overlap and cause pump to NOT shut down.


HERE is an off-the-cuff adjustment method

Ours did the same thing until this adjustment was done now runs smoothly w/o cycling.

People saying it's working correctly....I have read in the manual that cycling is bad and shortens the life of the pump?

Your Shurflo 4008 has TWO adjustments. \\\

One is for pressure switch....
One is for Bypass control

Bypass allows water to return suction side during low water demands

IF you do not adjust CORRECTLY then pressure adjustment and Bypass adjustment can overlap and cause pump to NOT shut down.


HERE is an off-the-cuff adjustment method