|Posted by Steve Whited on May 03, 2004 at 10:04:38:|
|In response to Re: WELL TROL PRESSURE TANK|
HOW TO CHECK AND RE-PRESSURIZE YOUR WELL TROLL WATER TANK FOR DUMMIES
I wrote this for all of the people out there like me that have one of these systems and are having problems with their unit. I'm a professional nobody and a devote member of P.T.S.O. (Part Time Screw Offs). This is based on my experiences and what I have pieced together from this site and a few others. So here is the official release of liability: I am in no way responsible for your mistakes or your actions. The people who run this forum aren't responsible for your mistakes or your actions either. If you choose to blow yourself up, mangle appendages on your body (or other people), or have sex with the wrong person it's your own damn fault, so don't blame us for your stupidity. Nuff-said�
The best way to solve your problem(s) is to understand how the gismo works. We can't really compress water to pressurize it. We can compress air and use its energy to "push" water out of the pipe faster (kind'a like blowing through a straw that is half filled with water). Below is a diagram of my system. I live on top of a hill and need to bring my water pressure up to a usable pressure.
The "Water Source" is just that, the water source, and in my case it is from the county and has a base pressure of about 12 pounds at the top of the hill. I also have a "Cut off valve" to stop the flow of water from the county. This most likely would not be present in a well configuration. The "Check Valve" is a one-way valve that will allow the water to move in only one direction (that way water can't flow back to source after the pump cuts off). Mine, for all the world, looks like a fat short piece of pipe with an arrow embossed in the top of it. The "Pump" is electric and controlled by a spring loaded pressure switch. The "Pressure Switch" is a spring loaded switch that is triggered by water pressure. The "Gauge" shows the current water pressure in the system. The "Pressure Tank" is an upright metal tank with a rubber bladder (think of it as a heavy duty balloon) built inside the top half of the tank and a water pipe somewhere towards the bottom of the tank. My tank actually has a "T" at the bottom for the water pipe. There is an air valve stem at the top of the tank to fill the bladder with air, this will look very much like that of an air stem that you see on the tires of your car.
Under normal operation (with all of our faucets closed), the pump draws water from the source and pushes it into the tank compressing the air in the bladder (remember, we can't compress water). The pressure switch, at some pre-determined setting, reaches its cut-off pressure and tells the pump to stop. When we open our faucets, we allow the compressed air to "push" the water out of the faucet (because for some silly reason the laws of physics say that every thing will always try to reach an equilibrium). Before the bladder can get back to its equilibrium, the spring in our pressure switch will overcome its pressure setting and then "cut-in" the water pump to re-pressurize the tank and the cycle begins anew. It is the balance between the Pump, Pressure Switch, and air in the bladder (inside the tank) where in lies the magic (and problems) of our water system. We need a big enough pump capable of "pushing" enough water beyond our maximum required water pressure. We also need the pressure switch and the air in the bladder to be balanced with each other. We basically want the pressure switch set 2psi higher than what is in our air bladder, and we want the air bladder to be no lower than what we want for a minimum of water pressure. I have also read that going beyond 50psi in pressure for household systems can lead to trouble (Busted pipes behind your walls? - sounds messy).
So, with our new found knowledge, let us begin checking our systems. You will need some basic tools and some way of re-pressurizing the air bladder in the tank. I have an air compressor, but a good quality bicycle pump will do. You will also need an air pressure gauge. I needed a 5/16" nut driver to fool around with the pressure switch; your switch may vary so use what is necessary.
First we have to determine if the air bladder is still serviceable. This is pretty easy and what we need to do is let out all of the air in our tank. We want to see if the bladder is ruptured. If it is, then water will come out of the air stem. This is a BAD thing and you should replace the pressure tank. You can let out the air in several ways. TURN OFF THE WATER PUMP!! I have an air valve core removal tool. This is a small toy that fits down inside the air stem and allows you unscrew the air valve. You can get one of these from the automotive parts store (or you may be lucky and find one built into the cap of one of your tire's valve stem like me ;-) BE CAREFULL!!!! There is pressurized air in tank and you can loose the air valve if you unscrew it carelessly. Of course the other option is hold down the valve and let out the air. I left the county water still running so this also help push out all of the air. If you have a well you may have to turn the pump on for short periods to force all of the air out. The pump may cycle on-off rapidly because as it hits it max pressure. Don't leave it running like this for long periods of time. The key point here is to determine that the air bladder is still in one piece.
Now we need to re-fill the air pressure in the tank. At this stage we should have the pump off and all of the air squeezed out of the air bladder. If you removed the air valve core like I did, then re-install it now. OPEN SOME FAUCETS IN THE HOUSE. We want to measure the air pressure in the air bladder with no resistance from the water in the tank. As I mentioned above, we want two pounds less of pressure in the tank than we have the switch set at. So, if we want to have a minimum of 30psi of water pressure we would have 28psi in the tank and we would have the pressure switch set to turn back on at 30psi. Start adding air pressure back into the tank. As you do this, you will be pushing water back out of the tank (Had you not opened some faucets then you would get a false reading on the air pressure). You need to wait until the water stops flowing before measuring the air pressure in the tank.
Once the tank is re-pressurized, we can set the pressure switch. My pressure switch was mounted on the side of the water pump and had a plastic housing that could be removed to expose the mechanicals. The bottom of the switch has a diaphragm with a small feed line which leads back to the pump. Inside the switch is a rocker plate with electrical contacts on one side. There are springs on both sides of the rocker plate with one of the springs being adjustable for tension. Tension on the adjustable spring is trying to close the switch (making the pump turn on) while water pressure from the diaphragm (along with the other set of springs) is trying to open the switch. As the water pressure decreases, tension from the adjustable spring will overcome the tension from the diaphragm and close the switch. The point at which this occurs is known as the "Cut-in" pressure. The point at which the water pressure is great enough to open the switch is known as the "Cut-off" pressure. We want the "Cut-in" pressure to be 2psi greater than what is in the tank (Hmmmm, I think I said that already�). My switches "Cut-off" pressure was not adjustable; however, it moved in conjunction with the "Cut-in" setting and was always 20psi higher than the "Cut-in" setting.
BE EXTREMELY CAREFULL!!!! THERE WILL BE ELECTRICTY PRESENT ON THOSE EXPOSED CONTACTS!!! DO NOT TOUCH THEM - YOU WILL NOT LIKE IT!!! Especially if your pump is wired for 220 volts!!
Open some faucets in the house (They should be still open from the step above). I turned the nut a few turns on the adjustable spring and reduced the tension a little bit. I then turned on the pump. If the pump starts to cycle on/off rapidly then you will need to increase the tension on the spring until it stops doing this. Eventually the pump should settle down into its normal operation and run up to the cut-off pressure (and turn off) then steadily drop in pressure (because the faucets are open and water is running) and hit the cut-in pressure (and turn back on). I just watched the pressure gauge on the pump and kept tightening the nut on the spring until cut-in occurred at 30psi. It took several cycles for me to get it right, but patience will be rewarding. Once every thing was set, I put the cover back on the switch and turned the faucets off. I now have water pressure and the pump operates normally.
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