# Another "solve this service call" from the world of Jlarson



## Bkessler (Feb 14, 2007)

Jlarson said:


> Ok lets see if we can't get some technical, educational, thought provoking posts going on, kinda like what was talked about here: http://www.electriciantalk.com/f2/remember-when-forum-about-electrical-19016/
> 
> 
> Awhile back I was called to t-shoot a irrigation pump that wasn't operating correctly. The pump pulled water from small water tank and pumped into a pressure tank then into the irrigation system feed lines out to each zone valve. The pump was a controlled by a pressure switch.
> ...


zone valve leaking?


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## Jlarson (Jun 28, 2009)

Nope, I had the irrigation guys check the zone valves and all was good there.


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## Bkessler (Feb 14, 2007)

pressure sensor in the pressurized tank was bad?


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## Bkessler (Feb 14, 2007)

something getting hot and then cooling down?


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## Jlarson (Jun 28, 2009)

Nope, I swapped switches with a new one of the truck and the problem still happened.

And all connections checked out.


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## Bkessler (Feb 14, 2007)

is it an electrical or mechanical problem, Ive seen broken impellers cause similar problems.


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## 480sparky (Sep 20, 2007)

I'm no help. It rains too much here for irrigation.:laughing:


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## Jlarson (Jun 28, 2009)

Bkessler said:


> is it an electrical or mechanical problem, Ive seen broken impellers cause similar problems.


Not an impeller. It is mechanical though.


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## Bkessler (Feb 14, 2007)

does this problem involve gravity?


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## Jlarson (Jun 28, 2009)

Bkessler said:


> does this problem involve gravity?


No, but gravity was present at the time :laughing:


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## 480sparky (Sep 20, 2007)

Vibration of some sort caused the float switch to jump up and down, causing the 'chattering'.


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## Bkessler (Feb 14, 2007)

Jlarson said:


> No, but gravity was present at the time :laughing:


is there an auxiliary contact involved? I need a hint.


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## Jlarson (Jun 28, 2009)

480sparky said:


> Vibration of some sort caused the float switch to jump up and down, causing the 'chattering'.


The tank level float switch circuit was separate from the pump controls. 



Bkessler said:


> is there an auxiliary contact involved? I need a hint.


No aux contact. Just a pressure switch pulling in a DP contactor to start and stop the pump.


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## Bkessler (Feb 14, 2007)

Jlarson said:


> The tank level float switch circuit was separate from the pump controls.
> 
> 
> 
> No aux contact. Just a pressure switch pulling in a DP contactor to start and stop the pump.


 I had a bad 3 pole contactor that as 480 accurately described chattered once. It was for rooftop unit in a science classroom. Replaced it and it worked fine.


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## Jlarson (Jun 28, 2009)

Contractor checked out fine.


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## macmikeman (Jan 23, 2007)

Was it a problem caused by somebody wired it with blue boxes?


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## macmikeman (Jan 23, 2007)

Ok serious, does the pressure tank have an internal bladder bag? More precisely an internal bladder bag with a pinhole in it?


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## Jlarson (Jun 28, 2009)

macmikeman said:


> Was it a problem caused by somebody wired it with blue boxes?


:laughing: No I don't think they had blue boxes in the 60's (ok maybe the install wasn't that old but the original EMT involved was connected with indent type fittings)


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## Jlarson (Jun 28, 2009)

macmikeman said:


> Ok serious, does the pressure tank have an internal bladder bag? More precisely an internal bladder bag with a pinhole in it?


No bladder in the p-tank at all, never was, not that type of tank.


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## frenchelectrican (Mar 15, 2007)

A pinhole leak on suction pipe which it can draw air in when the small tank is below the level of where the pinhole leak is.

Merci,
Marc


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## Jlarson (Jun 28, 2009)

No leak on the suction or the discharge side for that matter. I guess they made galvanized steel pipe better in the 'old days'.


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## kevmanTA (Jul 20, 2010)

Snake in the impeller!


The colder water has a higher density, causing the pressure switch to activate sooner.


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## Wirenuting (Sep 12, 2010)

You checked the lines, switch, tank, starter and motor. You say the empeller is ok and not worn down. Gravity was there at the time of your repair and there were no blue boxes. 
Makes me think something is floating in the pump housing or the check valve is not seating.


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## jwjrw (Jan 14, 2010)

Me thinks Jlarson is on site trying to t shoot this pump and is checking things as fast as we post them....:laughing::whistling2::lol::lol:


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## Wingnut (Jan 31, 2010)

back flow preventer bad


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## Wirenuting (Sep 12, 2010)

Wingnut said:


> back flow preventer bad


Don't think a backflow preventer as he's pulling from a tank so fresh water contamination shouldn't be an issue.


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## wayne g (Nov 28, 2010)

The pressure switch was satisfied, then pressure drop. This would go back & forth, I think because of the 2 tanks & setting of the pressue switch caused it to toggle back & forth.


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## BBQ (Nov 16, 2010)

jwjrw said:


> Me thinks Jlarson is on site trying to t shoot this pump and is checking things as fast as we post them....:laughing::whistling2::lol::lol:



You know it ............... freaking roofers doing electrical work. :laughing:


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## cobra50 (Aug 12, 2009)

Cogged filter on the feed side:thumbsup:


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## wdemos (Nov 27, 2008)

If the pump doesn’t have a net positive suction head it's probably a bad foot valve. Other wise check that the discharge check valve is holding.


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## millelec (Nov 20, 2010)

I'm thinking bad discharge check valve as well.


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## Jlarson (Jun 28, 2009)

The last two posts (discharge check valve) are getting warm but still not there yet.


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## Bkessler (Feb 14, 2007)

Jlarson said:


> The last two posts (discharge check valve) are getting warm but still not there yet.


A mechanical problem with the discharge check valve, was it installed backwards?

I hope I win something.


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## Thedroid (Dec 6, 2010)

What kind of pressure switch? I imagine it has a differential setting, and if so what are the settings? I've seen a similar problem when to large reciprocating compressors were ran in parallel. One would drop out and the pulse from the other comp would hammer the pressure switch causing the starter to cycle. Solved with a few snubbers.


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## Jlarson (Jun 28, 2009)

Bkessler said:


> A mechanical problem with the discharge check valve, was it installed backwards?
> 
> I hope I win something.


No the discharge check was going the right direction.



Thedroid said:


> What kind of pressure switch? I imagine it has a differential setting, and if so what are the settings? I've seen a similar problem when to large reciprocating compressors were ran in parallel. One would drop out and the pulse from the other comp would hammer the pressure switch causing the starter to cycle. Solved with a few snubbers.


A cheap SQD one with the plastic cover. But the one I swapped it with as a test was a nice Allen Bradley with dampening in it and the problem persisted it just slowed the cycling down a tiny bit.


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## Wirenuting (Sep 12, 2010)

Bad unloading valve.


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## Jlarson (Jun 28, 2009)

Wirenuting said:


> Bad unloading valve.


:no: 











.


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## BBQ (Nov 16, 2010)

Lack of 3M™ Scotchkote™?


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## Jlarson (Jun 28, 2009)

BBQ said:


> Lack of 3M™ Scotchkote™?


What, did we get sued for not using the trade marks? :laughing:


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## Bkessler (Feb 14, 2007)

The fetzer valve wasn't prepared with 3-1 oil or gauze,


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## Jlarson (Jun 28, 2009)

Bkessler said:


> The fetzer valve wasn't prepared with 3-1 oil or gauze,


Klein makes valves now? Do I have to smack it with a hammer to break it in :laughing:


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## Wirenuting (Sep 12, 2010)

Jlarson said:


> Klein makes valves now? Do I have to smack it with a hammer to break it in :laughing:


Ok your pushing this question for 12 hours now. 
Im sure you been up all night thinking of ways to keep us guessing. 
What was wrong???
I gotta know as my puppies wanna nap on the couch with me and I can't until you tell us.

And don't tell us it was solar powered on a cloudy day.


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## Frank Mc (Nov 7, 2010)

I was going to suggest the check valve on the suction line was leaking...but im guessing thats what you call a backflow preventor...??

Frank


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## Wirenuting (Sep 12, 2010)

Frank Mc said:


> I was going to suggest the check valve on the suction line was leaking...but im guessing thats what you call a backflow preventor...??
> 
> Frank


Up here in IL we call a backflow preventer a series of valves hooked to the fresh water line that feeds any equipment other then domestic water systems. 
We place check valves before and after pumps as needed. 
Our backflow preventers need to be certified yearly. 
Even landscape companies need to use them when they hook into fire hydrant's


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## 220/221 (Sep 25, 2007)

Hmmmmmm.....


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## Jlarson (Jun 28, 2009)

Frank Mc said:


> I was going to suggest the check valve on the suction line was leaking..


There we go :thumbsup: The pump really was reaching cut off (the gauge was just too jumpy to tell) and the discharge side check closed and the pressure dropped because of the stuck suction side check and the pump stated again stopped and started and so on and so on. 

The suction check was somewhere underground so I moved the pressure switch from the pump to the pressure tank upstream of the discharge check and all was well.


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## micromind (Aug 11, 2007)

Pressure tank waterlogged? 

If it doesn't have enough air in it, it'll hydraulic lock at some point. This will usually cause the pressure switch to chatter, then it'll eventually settle down. 

This will happen to a non-bladder tank if air isn't added once in a while, and it can happen to a bladder tank if the air has leaked out of the top.

Could also be guck in the line to the pressure switch, or even a leak there.

Rob

Nevermind, didn't see the last post.


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## micromind (Aug 11, 2007)

Jlarson said:


> There we go :thumbsup: The pump really was reaching cut off (the gauge was just too jumpy to tell) and the discharge side check closed and the pressure dropped because of the stuck suction side check and the pump stated again stopped and started and so on and so on.
> 
> The suction check was somewhere underground so I moved the pressure switch from the pump to the pressure tank upstream of the discharge check and all was well.


I don't think I've ever seen two check valves on a pump like this. I can't see the reason for it, but I can see plenty of problems because of it.

Usually, if the pump is flooded suction, there is only one check valve on the discharge side; if it is located above the water level, there's only one check valve on the discharge side; preferably below the water level.

Rob

P.S I wouldn't put the pressure switch on the pump if there was a pressure tank and no valve between the pump and tank. Always put pressure switches where there is minimum pulsations.


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## tommu56 (Nov 19, 2010)

Hey I'm new on here but lurking for a while.
It has to be it was wired in to a blue box:laughing:


tom


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## Jlarson (Jun 28, 2009)

micromind said:


> I don't think I've ever seen two check valves on a pump like this. I can't see the reason for it, but I can see plenty of problems because of it.
> 
> Usually, if the pump is flooded suction, there is only one check valve on the discharge side; if it is located above the water level, there's only one check valve on the discharge side; preferably below the water level.
> 
> ...


An EE did the plumbing DIY style, probably though the 2 checks was better .My repair is only temp anyway, we are putting in a bigger pump and new p-tank and controls.


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## wdemos (Nov 27, 2008)

Jlarson said:


> There we go :thumbsup: The pump really was reaching cut off (the gauge was just too jumpy to tell) and the discharge side check closed and the pressure dropped because of the stuck suction side check and the pump stated again stopped and started and so on and so on.
> 
> The suction check was somewhere underground so I moved the pressure switch from the pump to the pressure tank upstream of the discharge check and all was well.


When lifting water with a pump the suction line check valve is generally refered to as a foot valve.


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## Frank Mc (Nov 7, 2010)

wdemos said:


> When lifting water with a pump the suction line check valve is generally refered to as a foot valve.


Hi

I notice the irrigation people refer to it as a foot valve....in industrial afaik its been known as a check valve....

Frank


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## Jlarson (Jun 28, 2009)

Frank Mc said:


> I notice the irrigation people refer to it as a foot valve....in industrial afaik its been known as a check valve....


There is a difference. 

foot valve









check valve


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## Frank Mc (Nov 7, 2010)

Jlarson said:


> There is a difference.
> 
> foot valve
> 
> ...


Yes physically different but both perform the same function....

Thanks
Frank


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## Lsparky (Sep 28, 2010)

Foot Valve tells you where the valve is.....I have hooked up the controls for many of these type of pressure tanks...holding tanks and or deep well pumps most of the larger ones had both a tank and air compressor, pressure sw and liquid level sensors (all controls were on the tank) also had a air relief float valve. It worked perfect for years....just took a little more maintainace...always had the proper water / air balance. Just 2 cents from an old timer


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## miller_elex (Jan 25, 2008)

Is not the foot valve the check valve on the discharge of the submersible pump?

The funny thing about checks is, if one doesn't seat right, you can get some funky flow problems when pumps are in parallel. Some of those swing checks have a clean-out.

I don't do irrigation, but its a good idea to check strainers regularly. Everytime the plumber has been around, I'd find strainers with metal shavings and other junk inside.


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## Jlarson (Jun 28, 2009)

jwjrw said:


> Me thinks Jlarson is on site trying to t shoot this pump and is checking things as fast as we post them....


:laughing:

I'm not even sure I get cell service at that site. I should see next time I'm there.


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## 480sparky (Sep 20, 2007)

Jlarson said:


> :laughing:
> 
> I'm not even sure I get cell service at that site. I should see next time I'm there.



You mean you haven't fixed it yet? :001_huh::blink:


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## Jlarson (Jun 28, 2009)

480sparky said:


> You mean you haven't fixed it yet? :001_huh::blink:


I fixed it, they also had me look at and repair the 24Vac tank level controls while I was there, I replaced and re wired a 2" electric valve, rewired the control box, and pulled some new control conductors on top of re locating the pressure switch. It was a nice little extra. 

Now they want it all re done and larger pumps put in. :thumbup:


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## jwjrw (Jan 14, 2010)

Jlarson said:


> :laughing:
> 
> I'm not even sure I get cell service at that site. I should see next time I'm there.




That was one shot. 


You know we don't need an explanation for each pic.....some of us can see what you did early in your career and then later in your career.

That was two.


This is me taking up for you you hack.


Dude in AZ that is not a code violation.....that's called ROOFER STYLE! Most inspectors won't call you for it in a box here. At least a plastic one. We used to do it before smart boxes. I usually use old work clips on metal cut ins but think his install is actually a better install even if illegal in the nec.....but that does not count for squat it is JMO.


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