Correct placement of Flexcon Flow-Thru FT-18 pressure tank help.

Describe Problem_
Mounted inside my 1750 Gallon Water Cistern is the Grundfos SQE pump and a small 4 gallon pressure tank (Flexcon FT18). I have been told by well & pump guy the pressure tank should not be mounted in the cistern and horizontal isn't good either. I would like to move it to a different location but can't find installation instructions on the web.

Currently the 4 gallon stainless steel pressure tank sites inside my main water cistern attached in a horizontal position about 4 feet directly above the SQE pump.

Have been told the purpose of this tank is to provide some (electrical term) capacitance for the pump as it turns on and off while providing water pressure to the house. Flush a toilet get a drink of water the pump would just click on then suddenly off and that i have been told is bad for the pump. So the purpose is to be a bit of a spring so the pump doesn't surge. (this is what I have been told its reason for existence. )

Question #1 Must this 4 gallon pressure tank be as close to the pump or can it be anyplace in my entire water system as long as no check valve is between the pump and the FT18?

My thinking is that if the tank was moved from inside the cistern and placed in the garage but on the same cold water line it would perform the same action. There are no check valves between the pump and my water heater in the garage. Just the house with all it's water pipes and sinks and toilets. However if placed in the garage then the pressure tank would be basically the last thing on the line before the water heater.


Question #2, If I cannot or should not mount it in the garage, (other end of the house) can I mount it about 15 or 20 feet from the pump and tank. I have a good clean location and it would work well. It would be the first thing on the line from the pump before the house. It would be moved from inside the water tank and be outside in the elements, but I would put a small housing over it to protect it.


Two pictures are attached since pictures were requested.
Image called FT-18-post.jpg is the image of how the tank is mounted now.

Image called FT-18-Place-POST.jpg is the distance from the tank to a window where I would place this thing if my Garage idea isn't good.

Any help would be great Don't hesitate to ask me computer questions.
Water pressure / tank
Flexcon Flow-Thru
Model FT18
Manufactur date shows 09.03
Installation date is May of 2007

Type of pump?
Submersible__YES______
Two wire (no control)__NO______
Three wire (control box)__YES____
Wire Size_____? 10 gauge____ Wire Length__? 10 feet______
Pump is inside water holding tank.

Size of Pump?
Motor Horsepower?_____? think 1/2 horse_____
Pump Model #__Grundfox SQE__
Date Pump Installed__2007___

Pumping from?
Cistern tank___YES____
Depth to water_4 feet___
Pump Setting__? ____
Pipe Size__1 and 1/4 __"
Drop Pipe Material
PVC_YES_______


Pressure Tank?
Bladder or diaphragm tank (one pipe to tank)___4 1/2 gallon bladder _______
Size or model of tank_Flexcon Flow-Thru FT-18 _
Air charge in top of tank, with pump off and water drained____40 +/- 5 pounds last time checked_PSI

Pressure Switch Setting?
On 30, off 50 __? Unsure______

Pump Control Method?
Cycle Stop Valve model #__? controler is CU 301 _______
Variable speed control #___?_______
Pump Start Relay (sprinkler timer, no tank)__?________
Manually turned on and off__NO Auto__________

Pump Protection
Cycle Sensor_________
Pumptec_____________
Low pressure cutoff switch (lever on side)__________
Other__Water level in tank switch _____

Filters or Softeners___Filter and softener___________
Before or after pressure tank_AFTER both pump and tank__
Type of filter____1 inch line into compressed carbon single block filter from Home Depot____
Bypass available__Not yet can be installed if recomended______

Water Used For?
House Use__Yes_____ Number of baths__3__ Number of People__2___
High Flow Showers__? no clue ___gpm?
Plus/Or
Irrigation with timers________NOPE
Irrigation with hoses________NOPE
Heat Pump_~NOT ~ _gpm?


Problems Experienced
No Water__Nope
Water only part time__Nope_
Water at all times but weak__Nope
Air in water___Nope
Pressure surging___Nope
Water Hammer (noise)___Nope
Too Much pressure___Nope

Pump makes clicking or buzzing sounds__Sounds normal______
Pressure gauge reading__Set to 80__psi

Do you have, and know how to use
an Ampmeter and Voltmeter___Yes, I also have the Grundfos R100 controller that will control the CU 301 pump control panel. Great at soldering copper pipe and electronics. SUX at PVC piping.

Those pumps can be installed in wells hundreds of feet deep, which makes them hundreds of feet from the tank. I think the important thing is to keep the pressure tank and pressure transducer together.

Forgive my stupidity. What is a transducer? you mean the pressure sensor that is about 12 inches from the tank.

Yes and the transducer “pressure sensor” needs to stay within 12” of the tank. The whole idea of the flow through tank is to keep the water in the tank from getting old, stale, and contaminated. That is because with those variable speed type controllers, there is no pressure bandwidth to allow the use of any water from the tank. The water that is in the tank stays in the tank forever. The water in the tank would get nasty, and the next time the power goes off, the tanks air charge would shove this nasty water into the house.

So the “flow through” nozzle at the entrance to the tank circulates water inside the tank as water flows past it in the mainline. This hopefully keeps the water in the tank from turning green. Since the tank cannot be used to store any water, the pump must come on every time you crack a faucet open, even for just a small glass of water.

This makes the main purpose of the pressure tank to cushion the “pressure sensor”. The pressure tank and “pressure sensor” need to stay close together so the pressure tank can cushion the sensor from the pulses in pressure that happen when the pump starts, stops, changes speed, or when you open or close a faucet.

It is good that you are moving the tank and “sensor” out of the cistern tank. Because the place where the sensor is attached, is the same place you will need to install a regular 40/60 pressure switch when the CU301 controller quits working. Yours has already lasted longer than normal, probably because you don’t have any outside watering, and the pump apparently doesn’t get a lot of use. The age of that CU301 controller means that it is probably about the fourth of about six versions produced. Which means it will revert to cycling the pump on and off like a regular pressure switch, and will do this about 500 times before it shuts down and alerts you that the CU301 and motor have lost communication. This is usually when I get a call and show people how to replace the CU301 and “sensor” with a regular pressure switch, and where to add a Cycle Stop Valve to produce the constant pressure and keep the pump from cycling. Sometimes they don’t start looking for an answer until they have replaced the CU301 three or four times, and are very angry by the time they call me.