Originally Posted By: kbliss This post was automatically imported from our archived forum.
I am looking to buy a home in the N. Georgia mountains and I ran across something I am not use to. The home is new, and has public utilities. It is about 10miles out of town and has a shallow well pump in the basement with a little pressure tank on it. Is the pump there because the home is up in a small mountain and it needs a little more pressure because of the elevation?
Originally Posted By: Guest This post was automatically imported from our archived forum.
Kurt,
It may be a shallow well pump, but typically one would use a pressure booster pump. Most of the pressure booster pumps will give 50- 60psi and most shallow well pumps have a hard time with 50psi.
I'd check to see is it's in series with the municipal water supply. If it is then it's probably there to boost pressure.
It may be a remnant from pre-public water.
Chad
Originally Posted By: kbliss This post was automatically imported from our archived forum.
chad,
It is on public water supply, and I figured it was a booster. The pump says that it is a shallow well pump. The home is in the mountains so I figured it was a booster.
Originally Posted By: Guest This post was automatically imported from our archived forum.
Kurt,
The shallow well pump will boost pressure to the system, just not as well as a pump designed for that purpose. Typically, shallow well pumps come with a 20-40 psi switch...on at 20psi off at 40 psi. If they don't have to actually lift the water from the well a 30-50 psi switch could be used. The small pressure tank should be upgraded to a minimum of a 50 gallon rated tank. The bladder should be pressurized to a pound or two below the pressure switch cut in point. The upgrade in tank size will significantly reduce the on-off cycling of the pump which dramatically increases pump life. Chad
Originally Posted By: tgardner This post was automatically imported from our archived forum.
If you can supply a mfr, model, and S/N, I can get a performance curve e-mailed to you.
You should also be aware that you need a pressure guage on the suction side of your booster system to determine the Net Positive Suction Head available to your pump. You should probably not want to boost the pressure in your system above 60 PSIG as you may overpressure other parts and systems.
As for the size of the tank, it should be sized to allow the motor to run a minimum of one minute to dissipate the heat generated by the starting current.
To figure that out, you really need to know the pump capacity - hencethe perf. curve.
Originally Posted By: rhinck This post was automatically imported from our archived forum.
Be careful if this is a booster pump on a public water system. If the waterline would begin to leak you could contaminate your interior piping system. Just a thought
Originally Posted By: tgardner This post was automatically imported from our archived forum.
Good point - A low pressure cutoff of a minimum of 10psig should be used to prevent a lift situation where groundwater could be drawn in through a leak in the water main. Thats why one needs to know the NPSH available to the booster/shallow water pump. ( by the way, ALL centrifugal pumps can lift water some fraction of 33ft. Some as much as 25’; but most booster pumps, low flow - high head types can only lift 5-10’)
Originally Posted By: lschmid This post was automatically imported from our archived forum.
Kurt, We have a lot of those here in the upstate of SC. They are used mostly to boost the pressure to a house in the mountains on a public system. Probably will be fine, but if you find the pump short cycling, not running for at least a minute, you can add a cycle stop valve, about $75.00 to lengthen the run time and save on power. Easy for a do it yourselfer to install.
Originally Posted By: kbliss This post was automatically imported from our archived forum.
Larry
Thanks for the reply, that is certainly what the scenario is. I talked to the builder and he said the same thing you said as to the reason the pump was added.
Originally Posted By: lschmid This post was automatically imported from our archived forum.
Kurt, did he indicate if the pressure tank was waterlogged? Is the existing tank an older galvanized air injection tank or a newer air bladder type. If it is the first, you might be able to drain it, re-charge the air, check for leaks and proper valve operation, and still use it. If the latter, you will have to replace it. If the tank is ok, then a cycle stop valve would work well in this situation. Let me know if I can help. Most good places that sell pumps to well drillers can get these. Let me know if you need any help.
Originally Posted By: kbliss This post was automatically imported from our archived forum.
Larry
The house is a new construction on a well that provides water to the “subdivision” and our house is elevated. The tank on the shallow well pump is a small tank. Now I am going by memeory back in Nov. when I saw it. I would say the tank is about the size of a freon tank used to charge a/c units or the size of a tank used under a sink for a reverse ismosis system.
Why couldnt a bladder tank be used in this application. I really dont want to have to put one in, just wondering is all.
Originally Posted By: Greg Owens This post was automatically imported from our archived forum.
if it is new construction that tank should be under some type of warranty. make your builder repair or replace it because it should not be short cycling no matter what the situation is.
Originally Posted By: lschmid This post was automatically imported from our archived forum.
Kurt, if it is that new, probably is a an air bladder. If so, it should come with a 5 year manufactures warranty.
How often is the pump coming on and how long does it run?
It might be the builder put too small of a tank in for the pressure and flow of the pump.
I am the water systems operator for 6 such subdivisions here in upstate SC and several people have such a set up. Make sure the pump will produce the pressure you want in your house. I have mine set at 60 - 80 psi because I like a strong shower. All this needs to be taken into consideration when sizing the pump, tank, controls, etc.
If your builder needs any help, have him give me a call and I can help him over the phone.
Where about in the mountains is the home? There sure are some pretty spots on GA. We like to go over there sight-seeing.
Originally Posted By: kbliss This post was automatically imported from our archived forum.
Larry
The inspector said it cycled on and off when ever a faucet was opened or a toilet was flushed, sounds to me like it is not pressurized properly. Too much air? Like I said it is small not like a bladder tank I`ve ever seen.
The home is in Blairsville, Union county, do you know where that is?
Originally Posted By: lschmid This post was automatically imported from our archived forum.
Kurt, I think you need someone to look at it. If the tank is waterlogged, it could cycle with a cup of water. This short cycling will eventually harm your pump. Much cheaper to fix now than later.
Originally Posted By: tgardner This post was automatically imported from our archived forum.
Kurt,
Because your pump is a booster, you will need to reset the tank precharge pressure to match the system pressure in your house. Here is the procedure:
All water system tanks are precharged at the factory. All 8 and 11 inch diameter tanks are precharged at 18 psig. The 15
inch diameter tanks are precharged at 28 psig while the 22 and 26 inch diameter tanks are precharged to 38 psig. The
final precharge pressure should always be 2 to 3 psig below the cut-in (pump turns on) pressure of the pressure switch.
Release air or add air as required using the following procedure.
1. Determine the pump cut-in pressure setting. The pressure switch should have this information located on/in the
cover.
2. With no water in the tank, measure the precharge of the water system tank using an accurate pressure gauge at the
air valve (similar to an auto tire gauge).
3. Release air or add air to the tank to make the pressure in the tank 2 to 3 psig LESS than the pump cut-in pressure
setting.
If the system pressure is higher than the originalcut-in pressure of the pump pressure switch,(as may be the case at your house) the pump installer may have adjusted the switch without re-setting the precharge, which would cause short-cycling.
If the tank is a small 8" dia tank then the pump will start after about 1/2 gallon of water is released from the system. This would appear as short-cycling
If the tank is a small 11" dia tank then the pump will start after about 1&1/2 gallon of water is released from the system. This would be in about 30 seconds with a standard faucet at 3gpm.
Originally Posted By: kbliss This post was automatically imported from our archived forum.
Larry,
I have some more info on this subject. It is a Potable Water Expansion Tank. I was just up at the house so this is what I found. There is a shallow well pump with this water exspansion tank plumbed onto the well pump. By the way the water is city water and this is merely a “booster” because the water has to travel up the hill.
The tank is very small, the size of a volleyball. It is pressurized and it set for 50-30/ cut on cut off.
The pump cycles every 15 seconds when the water is flowing from a sink faucet. I have brought this to the builders attention. To me the tank is so small that it is worthless, why not just put a bladder tank in?
Originally Posted By: Guest This post was automatically imported from our archived forum.
The tank is too small. This is a case where big is always better.
An 80 gallon tank would completely eliminate the short cycle effect and water pressure would be more consistent. Pump life would be dramatically improved over the current set up. They’re not terribly expensive. At a wholesaler expect to pay in the 300 dollar range for a tank this size.
