shurflo 9300 submerible - low flow

gpigeon

I have had one of these 9300 series pumps operating for several years without a problem. However the flow rate has recently (maybe over a period of time) dropped to 2.1L/min @ 0 psi and 1.4L/min @ 30 psi.

I dismantled the pump and there was no obvious problem with the components, nevertheless I installed a new valve kit and lower housing kit. Plus cleaned the graphite dust out of the motor & checked the brushes.
The pump output is now 6.8L/min @ 30 psi which is good. So I fixed the problem but I'm not sure what the problem was.

Does anyone know if the wear on the valve components is obvious to the naked eye?
Do the rubber bits lose their elasticity over time and cause the problem?
Is 3 years about the life expectancy for the valve components?

Any info, experience with these pumps would be appreciated.
Thanks.
Bill W.

Blackcherry04

Re: shurflo 9300 submerible - low flow

My experience with a diaphragm pump it's usually the lower housing that wears and the diaphragm's do not get the lift they once had. It's a wobble plate or cam that lifts each diaphragm on rotation and creates suction . Each one has a little different scheme, but the principal is the same. The valves also serve as their own check valve's, so yeah they could wear and not seal and leak back, then the water just runs around in a circle with no volume. You did the right thing, replace both and enjoy.

gpigeon

Re: shurflo 9300 submerible - low flow

Blackcherry04.....thanks for the reply. I think you are right about the little pads behind the diaphragm wearing and thus there is less lift each time the swash plate rotates. I suppose these little pumps do a marvellous job considering that they run for 8-10 hrs per day for 2 or 3 years. Unfortunately shipping cost from the US is a real killer, but that is coming right again now with our Aussie$ back up to around 95c. Thank you Mr. Benanke!!!!!!
Rgds.
Bill.