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Discussion Starter · #1 ·
I make no claims at pump expertise. Any time a pump thread is started I STAY AWAY. But yesterday I moved a pump to higher ground for a customer. Electricity and all. Job of course came out beautiful but here is my question. These folks almost burned up their pump. The creek was lowered for wall rebuilding and I guess the water drained out and it lost its prime. They should have a thermal? (not sure of my terminology and too lazy to do a word search) cutoff to protect the pump. Here is my question. Can that be installed at the pump without running additional wiring? They have a pump start relay in the garage some distance away. How can I protect this pump?
 

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Pete, the pump start relay is just a relay that turns the power on and off. Somewhere, there should be a "pump start" that is protected. It could be an external capacitor with re-settable breaker, or it could be an internal with a reset button on the motor, or a fused link/breaker on a contactor, etc. Like everything else we seem to touch in this business, there are lots of variables and it is hard to "see" exactly what is going on without lots more information.
 

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Typically, on centrifugal pumps, run temperatures are not the cause of impeller bearing failure - loss of prime is. And depending upon the type of impeller casing (stainless steel verse ductile iron) and impeller casting, some pumps are actually rated to run "dry" for a few minutes without seizing the impeller bearing.
The main problem about thermal sensing switches here in Texas is the radiant heat an electric motor emits when operating. Add ambient heat to this and already these motors are approaching threshold levels that would ordinarily "trip" a thermal breaker.
About the only suggestion I have is to look for some type of discharge line flow rate meter that would interrupt the electrical circuit to the motor if the discharge rate didn't meet a pre-set value.
 

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Discussion Starter · #5 ·

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Discussion Starter · #6 ·
Typically, on centrifugal pumps, run temperatures are not the cause of impeller bearing failure - loss of prime is. And depending upon the type of impeller casing (stainless steel verse ductile iron) and impeller casting, some pumps are actually rated to run "dry" for a few minutes without seizing the impeller bearing.
The main problem about thermal sensing switches here in Texas is the radiant heat an electric motor emits when operating. Add ambient heat to this and already these motors are approaching threshold levels that would ordinarily "trip" a thermal breaker.
About the only suggestion I have is to look for some type of discharge line flow rate meter that would interrupt the electrical circuit to the motor if the discharge rate didn't meet a pre-set value.
Thanks guys. I'll contact my pump guy at Longhorn and get him on this. Will post his suggestions.
 

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About the only suggestion I have is to look for some type of discharge line flow rate meter that would interrupt the electrical circuit to the motor if the discharge rate didn't meet a pre-set value.
There is a flow-sensing relay out there, will have to think on it to come up with the name. Essentially you program a low and high flow rate, then the relay takes over and shuts pump off if either value is met.
 

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Do they own this creek or water source?

I use submersibles for most of my private water installs. Since they already have the relay, and the wiring it would be an easy install.

Around here a 1 hp 20 GPM submersible runs about $375.

I know this does not answer your question, but just some food for thought.
 

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Discussion Starter · #9 ·
Do they own this creek or water source?

I use submersibles for most of my private water installs. Since they already have the relay, and the wiring it would be an easy install.

Around here a 1 hp 20 GPM submersible runs about $375.

I know this does not answer your question, but just some food for thought.
I talked to them about that. The creek is only waist high and when it rains becomes a raging flood getting 10-12' high. We decided that it wasn't feasible and the neighbors aren't too keen on seeing electricity going into the creek. If it was a pond or lake would be a no-brainer.
 

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Discussion Starter · #11 ·
I use this product to operate a pump that pumps from a river.

http://www.shop.aquasolutionsplus.com/product.sc?categoryId=9&productId=16

This controller starts the pump based on flow and stops the pump when the flow stops, it includes a provision that stops the pump when it has lost suction. Let me know if you have questions as I have used one for at least five years.
Quick question before I head out for the day. That showed 1 and 1.25 sizes. I'm assuming it is inline. (Don't have time to read now but will read later) I'm dealing with a 2" mainline?
 

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Quick question before I head out for the day. That showed 1 and 1.25 sizes. I'm assuming it is inline. (Don't have time to read now but will read later) I'm dealing with a 2" mainline?
Size doesn't matter. I use a two inch line as well, the controller is in a 1 inch line with a 2 inch bypass and a valve, I close the two inch valve slightly to force flow throught the controller.
 

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Here is a solution that works much better than those Mass Control things. Mass Control works fairly well with low pressure booster pumps but, I have burned up a lot of submersibles with those. I no longer use them.

http://www.pumpsandtanks.com/Motors-Switches/overheat_protection.htm
Respectfully I disagree.

I have used a MasControl for five or six years now, I have no affiliation with them what so ever, I have just had really good luck with them and don't mind promoting I product that works very well for me. I understand that you may have had issues with deep well submersible pumps and MasControl, but I use mine with a multistage centrifugal pump on shore and it is great. I can see issues with a MasControl unit being used in a home environment when the water is being started hundreds of times daily, in my application the pump is started once and shut off once per day. I do believe if I remember right that the OP is asking about a centrifugal pump on shore not a deep well submersible so I guess that doesn't matter
 

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The Mass Control works OK as long as everything is perfect. The smallest leak in the system will cause the pump to cycle on and off every 8 seconds until the pump is toasted. If you don't plan for a leak and have some way to handle it, it is just a matter of time until you find out what I am talking about. Your systems have been in long enough that some leaks are going to develop, then everything will go south all at once.
 

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Discussion Starter · #17 ·
The Mass Control works OK as long as everything is perfect. The smallest leak in the system will cause the pump to cycle on and off every 8 seconds until the pump is toasted. If you don't plan for a leak and have some way to handle it, it is just a matter of time until you find out what I am talking about. Your systems have been in long enough that some leaks are going to develop, then everything will go south all at once.
The pump only kicks on when it has been activated by the timer. It has a pump start relay ( I believe that is what it is called) in the garage by the breaker box. So no power is at the pump until it has been activated by the controller. I'm guessing this eliminates the small leak concern which would be a problem with pressure activated pumps I'm guessing. My main concern is it running continuously when it has lost its prime and/or when a valve fails to open for some reason. I like the idea of it shutting down due to no flow rather than temperature. Any further info I should consider?
 
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