Craigpump
In the Trades
The only time I've seen galvanized under PVC is if the pump continues to run dry and melt off the pipe.
About to drill well - Need Advice
- Thread starter Pettrix
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I don't mind it at all if the customer wants to spend the extra money. I was just saying their is nothing wrong with using galvanized fittings as we use them too.
Here is a 5hp Berkeley on galvy for you thirdgenpump, from the early 80's that finally got the wire but it also wasn't wrapped the way you want to be on saving your wire till pump gives out. This system is still using all the original galvanized fittings as well up top.
I saved the bottom picture for you craigpump, it's for your question on multiple check valves only having problems with bigger gpm pumps. These 3 check valves are from the early to mid 70's that have 2 3hp 25gpm pumps on them and they are still holding up to all the cycling from only 1 tank. The original 5hp 60gpm pump on the system before the 2nd well was drilled is still working somewhere else for them on it's original check valve down the well with only 1 tank too. All 3 of these systems are on PVC drop pipe with galvanized couplings and no torque bumpers. They are all lasting without a flow sleeve as well. They are in the upthrust condition and when one them fails finally, I will break it open to show how they have downthrust wear Not Upthrust Wear.
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I am leaning towards ALL Sch120 PVC drop pipe. Don't want to deal with galvanized pipe.
If the 5HP pump does a soft start/soft stop with a torque arrestor on the PVC pipe, that should soften the wear and torque on the PVC pipe, right?
Craigpump
In the Trades
You will need numerous torque arrestors to keep the pump stabilized and prevent the wire from getting chaffed on the borehole. If it were me I'd use flat double insulated pump cable, more money but worth it.
That depends. If the VFD has a pressure transducer the soft start works fairly well. But you can't do a real soft start with a submersible as it has to get to 50% speed in one second to prevent running the thrust bearing dry.
Now if the VFD has a switch instead of a transducer like the Franklin Subdrive, it is a soft start, but it can soft start 45 times a minutes as that switch makes and breaks over and over. All that torquing is what will wear on the drop wire.
Craigpump
In the Trades
....and 45 times a minute doesn't do the transducer diaphram any good at all.
Craigpump
In the Trades
Pump companies say lots of things....that little diaphram in the transducer is like the diaphram in a tank. Bend it enough times and it fails. Or gets shit in it and fails, if your lucky it doesn't over run the pressure relief valve and flood the basement.
All I know is that we replace a lot transducers a year
All I know is that we replace a lot transducers a year
How many cycles do you think that Subdrive75 that I posted did in 10yrs?
Haven't had any problems with mine and they are a switch craigpump.
https://franklinaid.com/2007/03/25/how-subdrive-and-monodrive-measure-water-pressure/
Haven't had any problems with mine and they are a switch craigpump.
https://franklinaid.com/2007/03/25/how-subdrive-and-monodrive-measure-water-pressure/
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“The SubDrive/MonoDrive pressure sensor works just like a standard water system pressure switch.”
Except;
“It opens and closes in response to small changes in water pressure. Remember, the switch has a resolution of less than ½ psi.”
Standard switches have a resolution of 20 PSI. Big difference!
“The switch is capable of millions of cycles.”
How many millions? 45 times a minute would be 23,652,000 per year. I don’t think they mean that many millions.
“Like many things, the simplest way to do something is often the best.”
I agree! But I can’t believe they said that! There is nothing simple about a VFD.
I thought you had a 25 gpm pump, cycling 300 times per day, using a 20 gallon/5 draw pressure tank, and has already lasted 20 years?
And yes they are a switch, not a transducer. But they have a diaphragm similar to a transducer and Franklin isn't very clear about this. Many times they call it a "sensor", which is why it is confusing.
Do the Goulds VFD systems use a similar setup like the Franklin?
I can't find where they said that. But if it is true then they are not testing in real world conditions, or longer than a couple of months.
No the Goulds uses a pressure transducer, which has a whole different set of problems. Those problems have been well known for years, which is why Franklin went with the switch instead, trying to solve some of the problems of transducers. From the frying pan into the fire!
Craigpump
In the Trades
I've got one customer who goes through at least one a year on her irrigation system. In fact, we have an extra one on the shelf next to her tank.
I'd like to take the POS VFD out and replace it with a dumb pump and CSV, but the wire is too small and they don't want to trench in another conduit and wire....
I'd like to take the POS VFD out and replace it with a dumb pump and CSV, but the wire is too small and they don't want to trench in another conduit and wire....
Low Voltage/Low Current – A conventional pressure switch operates at line voltage, generally either at 120V or 240V. The SubDrive/MonoDrive sensor operates at less than 5 volts and at a few milliamps (a milliamp is one-thousandth of an amp). This means that as it opens and closes, there isn’t enough voltage or current for “arcing or sparking” to occur. This, in turn, means there’s never any “pitting” or corroding of the contacts.
◾Sensitivity – A conventional pressure switch generally operates with a 20 psi swing. That is, 30 to 50 psi, 40 to 60 psi, etc. The sensor used in SubDrive / MonoDrive is much more sensitive and open and closes with pressure fluctuations of less than ½ psi.
◾Duty Cycle – The SubDrive/MonoDrive pressure sensor is designed for literally millions and millions of cycles. As a matter of fact, we’ve never been able to wear one out in our laboratory life cycle testing.
◾Proven Performance – The SubDrive/MonoDrive pressure sensor is not unique to Franklin Electric or even to water systems. This same type of sensor is used in a myriad of commercial, automotive, and industrial applications.
They are right in my books!
Then you need a new book!
call Franklin because I haven't had to change one yet and I would like hear what they got to say about your problem.
Craigpump
In the Trades
The rep doesn't want to know anything about it.
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