brianander said:
I'm 200feet from the water meter on the street in a 3000sq/ft house, city water - pressure at all fixtures 64psi. When any fixture is used pressure drops to 40psi, then if second is used, falls to 21psi. Very little volume if more than one fixture is used at a time.
Could I use a boost pump to increase volume to keep up with demand? It's getting old turning off the clothes washer to take a shower or being restricted to just one shower operating at a time!!
Thanks for any help!
The line from street to house is too small.
Even with a booster pump, you will be limited to what the line can deliver at zero PSI at your house. It is unsafe to pull a vacuum in the line from the street because a leak could cause contaminated ground water to enter your system.
Therefore, you need a booster pump
and a storage tank.
Almost any small 1/2 HP shallow well jet pump will give you what you need to pump into a bladder tank. You could use a multistage centrifugal booster but that would produce more pressure than you need and costs more.
The size of the tank depends on how much water you want to use in a short time in excess of the capacity of the line from the street. A small tank will not work if your demand exceeds the capacity of the line. You need some storage to get over that demand hump.
You can't know the capacity of the line without some tests. I would skip the tests and use a large enough tank to be sure; probably an 80 gallon bladder tank unless you have a lot of demand over a long time such as multiple showers plus a washing machine.
You will need a relief valve on the tank setup for safety because the pump + city water pressure will exceed the safe pressure limit of the tank. You will also need a check valve on the suction side of the pump to prevent backflow at shutoff.
You can experiment with pressure settings. I would set the pressure switch at about 50 to 70 psi with precharge of 40 psi. The lower precharge will give you a little more capacity if you have more peak demand than the city line can't keep up with. The higher shutoff pressure will reduce the cycling on the pump.
The city pressure will keep filling the tank when the pump is off so you will be operating over a 50 to 64 psi range. The pump not run unless your demand exceeds the drawdown capacity of the tank between 64 and 50 PSI.
PS: Answers from Terry and Boots came while I was writing. If the bigger pipe is available, that is the best option. I was trying to answer the booster question.