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Fettb

New Member

1

Wednesday, July 11th 2018, 10:38am

Weird pump issue

Hi Folks!
I had a strange issue with my irrigation system this morning that I thought I would share and hopefully get some feedback.
Here's the scoop.
First, I designed and installed this system 1 year ago and it has run flawlessly since that time.
My system draws from a lake via a 2" diameter 125' long line connected to a submerged well point which serves as my intake screen. The intake line has a pvc flapper check valve at the point end AND a brass check valve at the pump intake. It takes about 45 minutes to self prime this line each spring which is why I have the two check valves to make certain I always have water.
For the past few days I noticed low flow from my heads so last night I cleaned my point and ran the irrigation program to verify flow was fixed. Everything worked great.
Fast forward to this morning at 7am when I looked out the window and saw that the sprinklers were not running (the program starts at 5:30 am and runs for 3.5 hours). I checked the pump and it WAS running. I touched the pump with my hand and it the Gould 1.5 HP jet pump was hot enough to hurt! I killed power, check intake (good) and turned the hose on the pump to cool this thing down. Given that it has been 90 deg and no rain for weeks, I needed to get this thing running ASAP. I pulled the prime screw and used my hose to force lots of water in there and then put the screw back in. I then fired up the pump and my heads kicked on in 15 seconds.
I originally assumed that I had lost prime in my intake hose (or was sucking air), but when the heads kicked right on I KNOW that is not the case. I clearly had water in that line up to the check valve/pump. So why was my pump not pulling water? All I can figure is that the pump itself was dry and therefore not pulling, but where in the heck did the water in the pump go and how did it escape?
If I don't understand why or how this happened, I am doomed to repeat this failure and doomed to have a pump failure due to an "unexpected thermal event" . Any thoughts or ideas about this? I'll post an update tomorrow for the benefit of the forum with an update to see if it repeats the event.
Thanks in advance for your input!
Brian

Wet_Boots

Supreme Member

Posts: 5,288

Location: Metro NYC

2

Wednesday, July 11th 2018, 5:07pm

Suspect suction side issues. A Goulds jet pump should hold prime on the strength of it having the inner diaphragm. Consider swapping out the well point for something way bigger, like a VuFlow 4BSK60, and even then, you might want heat protection for the pump, in case of a repeat failure.

By the way, sometimes when a pump overheats, the suction connection might need to be redone, especially if it's PVC entering the pump.

Fettb

New Member

3

Saturday, July 14th 2018, 3:12pm

Update -fixed

I found the issue! I have a coupling at the waters edge so I can pull the intake in the fall. This coupling was sucking air! I ditched the coupling and put in a metal barbed connector. I then found a 2” rubber coupling that I installed over the whole joint. It’s airtight as can be now! I fired up the pump and it sucked out that 125’ line in less than 5 minutes and was pushing good water. Pressure is perfect and sprinkliers no longer spit air.

Life is good! Thanks for the feedback!!!

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