I have a Grundfos Submersible pump with a Pumptrol Square D pressure switch, my water pressure fluctuates why?
July 30th, 2009 | 
Author: The tank says 75 psi and is 120 gallons. The guage on the side of the tank was down to 9% which is the lowest I seen. I have bled the air out making the pump kick in raising the water pressure, but the next time I use water it drastically falls again. I was not given any owner’s manuals. There are air valves on the side of the tank and on the pipe leading into the tank from the well. Should they have caps over them? There seems to be too much water in my yard even with the recent rains from cold fronts.
it sounds to me that you do not have a pressure regulating valve after the pressure tank.
a pressure regulating valve keeps the pressure in the house a level 60 psi or higher if needed.
pressure in the tank from the pump should fluctuate from 65 to 110 psi. IE the pump kicks on at 65 psi and off at 110ish
that is if you have air in your pressure tank.
http://www.wattsdrainage.com/pro/_productsFull_tree.asp?catId=64&parCat=285&pid=776&ref=2
You should have something that looks like this.
Do not bleed the air out of the tank.
The air is what gives you continous pressure.
Water can not compress, it is the air that gets compressed inthe top of the tank and then pushes the water out. If you do not have air you are only getting pressure from the pump, and it is made to turn on for 2 min then off again.
i would pump the air in the tank with a hand pump when the pump is off and give it 10 pumps,
you do not want to burst the air blader that is inside.
web site http://www.amtrol.com/wellxtrol.htm says air pressure in the tank was preset at 30 psi. and that is with no pressure to the tank.
Yes the air valves should have caps on them
Posted in Submersible Water Pump
it sounds to me that you do not have a pressure regulating valve after the pressure tank.
a pressure regulating valve keeps the pressure in the house a level 60 psi or higher if needed.
pressure in the tank from the pump should fluctuate from 65 to 110 psi. IE the pump kicks on at 65 psi and off at 110ish
that is if you have air in your pressure tank.
http://www.amtrol.com/wellxtrol.htm says air pressure in the tank was preset at 30 psi. and that is with no pressure to the tank.
Yes the air valves should have caps on them
References :
just did this in 3 houses this year
sounds like you have one of the following – a tank without a separate air bladder, a leak on the air side of the tank, or if you say you are bleeding the air out of the valves, you are causing your own problem.
our horse barn has a similar problem, we have a tank without an air bladder inside of it and once a month i have to shut the pump off, drain the tank empty, then refill it. the air in the tank compresses and gives us the pressure at the faucets.
also the watrer in the tank can and does absorb air resulting in a loss of air volume in the tank and an increase in water which causes your pump to cycle on and off frequently ( which is very bad for a welll pump )
also your pressure switch should not be located below the water level of the tank, it should be on the top – they arent designed to respond to change in pressure from the water, only from the change in the air at the top of the tank.
you may need to change the tank, or the pressure switch might be defunct – either way it’s a job for someone who does this work for a living
References :
source??? practical experience and my best friends a plumber
Not trying to sound mean but do not mess with stuff you do not know how to fix. Your going to have to call a pump installer to come out and drain your pressure tank, recharge your pressure tank, adjust the switch, ect…. water systems are a little finiky.the pressure in the should never be above 70 psi or below 40 psi. nominal pressure is 60 psi. you get the most gallons plus best pressure. any more than that you lose gallons more pressure less than 60 you increase gallons but lose pressure.
References :
4th generation well driller and pump installer