low pressure in second home
#1
07-03-13, 05:42 PM
low pressure in second home
We have a 3/4 hp pump for our well and the pressure tank is in our barn 150 ft from the house. The line from the pressure tank to the house is 3/4 poly, under our house it is 1 inch pvc. The trouble occurs because we are also feeding our daughters house from the same line. After our house we continue feeding another 150 ft to her home with a 1 inch poly and is probably reduced to 1/2 because it is a newer mfg home. She will loose pressure when we are using our water. I have a check valve as it leaves my home. so could I install a pressure tank under her home with a booster pump to bring pressure up to adequate?
#2
07-04-13, 04:47 AM
The best way to do this is to increase the size of your pressure tank capacity. Most houses have undersized tanks anyway and then to add another house without increasing the tank capacity makes the original problem worse. Note that I am using the word "capacity" here.
When you exhaust all the water in the tank, then the only pressure you get is from the pump and many pumps can't keep up with the demand while supplying the desired pressure, which is why we have pressure tanks to begin with.
There are two ways to increase pressure tank capacity:
1. Put in a larger tank. When you see a "100 gallon" tank, it doesn't hold 100 gallons of water. At 60PSI, it really holds about 40 gallons with the rest being air.
2. Manifolding another tank to the existing one. You can do this, and I have seen up to three tanks manifolded together. Note that there should be no check valves between them. They need to be exactly equal in pressure, but not size.
Putting a tank down-line will not work as well because the pressure coming to the second tank will not be steady and trying to put in a second pressure switch is playing a fools game -- you will never get that right.
So go to where the original tank is and figure out how to increase capacity. I hope your barn is big enough.
And I am not sure, but I don't think that check valve after your house is helping anything. It would "starve" the second house when you reduced the pressure in the first house. Both houses should be at the same pressure, just as it is at the tanks. It will never be exactly the same, but that's the goal. So if you set the pressure at the tank for 40/60, the second house may have something less.
Here is a size calculator:
Residential Water Tank Sizing Calculator | WELLMATE Composite Water Storage Tanks
Here is an installation manual:
http://wellmate.com/Files/KnowledgeB...all-manual.pdf
When you exhaust all the water in the tank, then the only pressure you get is from the pump and many pumps can't keep up with the demand while supplying the desired pressure, which is why we have pressure tanks to begin with.
There are two ways to increase pressure tank capacity:
1. Put in a larger tank. When you see a "100 gallon" tank, it doesn't hold 100 gallons of water. At 60PSI, it really holds about 40 gallons with the rest being air.
2. Manifolding another tank to the existing one. You can do this, and I have seen up to three tanks manifolded together. Note that there should be no check valves between them. They need to be exactly equal in pressure, but not size.
Putting a tank down-line will not work as well because the pressure coming to the second tank will not be steady and trying to put in a second pressure switch is playing a fools game -- you will never get that right.
So go to where the original tank is and figure out how to increase capacity. I hope your barn is big enough.
And I am not sure, but I don't think that check valve after your house is helping anything. It would "starve" the second house when you reduced the pressure in the first house. Both houses should be at the same pressure, just as it is at the tanks. It will never be exactly the same, but that's the goal. So if you set the pressure at the tank for 40/60, the second house may have something less.
Here is a size calculator:
Residential Water Tank Sizing Calculator | WELLMATE Composite Water Storage Tanks
Here is an installation manual:
http://wellmate.com/Files/KnowledgeB...all-manual.pdf
Last edited by Vey; 07-04-13 at 05:12 AM.
#3
07-04-13, 06:24 AM
Group Moderator
You did not say the gph and pressure capacity of your pump. Depending on it's specs it might not be enough. Increasing the pressure tank capacity can help reduce the frequency of when it's inadequate but will not stop it. If the pump can provide 5 gpm at 30 psi but when both houses are using water consume 7 gpm eventually and regularly empty the pressure tank, the pump will turn on but because demand is greater than it's capacity it will never "catch up" and will not be able to recharge the pressure tank until demand drops.
And, since you provided all your pipe diameters and lengths I think you are on the right track thinking that that is also contributing to the problem. Add in the resistance of each fitting along the way and it does add up to a significant amount.
A booster pump at the second house could be a solution though I don't know enough to say how it would work if it's inlet is restricted. With a booster pump you'd still have the same well pump providing water through a long piping run so the booster could be starved.
And, since you provided all your pipe diameters and lengths I think you are on the right track thinking that that is also contributing to the problem. Add in the resistance of each fitting along the way and it does add up to a significant amount.
A booster pump at the second house could be a solution though I don't know enough to say how it would work if it's inlet is restricted. With a booster pump you'd still have the same well pump providing water through a long piping run so the booster could be starved.
#4
07-04-13, 08:11 AM
Member
Unfortunately the other two have provided most or more info than I was going to post. One suggestion I would have (being a bit of a must know guy) is to add a pressure gauge at the inlet of both houses. You could add one on both sides of the tee as well, but it won't give you as accurate info.
With no water demands, you'll be able to see what your baseline pressure is at both points. 60PSI at your pressure tank will not mean 60PSI at each house. Pipe diameter will affect pressures (not so much volume unless major restrictions).
If you turn on a fauset at the first house, how much of a pressure drop do you see at the second?
In theory, both houses should see the same pressure at rest. In reality, it won't be the case.
Pressure gauges are pretty cheap (~$10CND plus ~$4 in fittings to attach). They make isolating issues a lot easier.
With no water demands, you'll be able to see what your baseline pressure is at both points. 60PSI at your pressure tank will not mean 60PSI at each house. Pipe diameter will affect pressures (not so much volume unless major restrictions).
If you turn on a fauset at the first house, how much of a pressure drop do you see at the second?
In theory, both houses should see the same pressure at rest. In reality, it won't be the case.
Pressure gauges are pretty cheap (~$10CND plus ~$4 in fittings to attach). They make isolating issues a lot easier.
#6
07-04-13, 10:15 AM
Member
What do you guys think about that check valve after the first house?
#7
07-04-13, 10:38 AM
Group Moderator
I would get rid of the check valve. I don't see what benefit it provides yet it is one more flow restriction.
I think the pressure gauges are a good idea to help diagnose and understand what's going on. With no water being used the pressure at both houses should equalize. But with water being drawn you'll be able to see how much the pressure is dropping. You can vary the usage volume and by location and will soon learn the limit of the system. I assume you'll find that one or two fixtures flowing in the first house are OK. Or, one fixture in the second house is OK but if you have high demand in both the pressures will suffer.
At the minimum you might simply be able to alter your usage patterns. The first house does laundry on Saturdays while the second does laundry on Sundays. First house runs the dishwasher in the morning while the send runs them at night...
I think the pressure gauges are a good idea to help diagnose and understand what's going on. With no water being used the pressure at both houses should equalize. But with water being drawn you'll be able to see how much the pressure is dropping. You can vary the usage volume and by location and will soon learn the limit of the system. I assume you'll find that one or two fixtures flowing in the first house are OK. Or, one fixture in the second house is OK but if you have high demand in both the pressures will suffer.
At the minimum you might simply be able to alter your usage patterns. The first house does laundry on Saturdays while the second does laundry on Sundays. First house runs the dishwasher in the morning while the send runs them at night...
