Pressure loss

Users who are viewing this thread

Shad

New Member
Messages
17
Reaction score
3
Points
3
Location
Texas
If I buy a 1hp jet pump to replace the city 1 hp pump what size pressure tank will I need. My 2 story house is 280‘ away on a 50’ hill. They supply line is 1”.
 

Valveman

Cary Austin
Staff member
Messages
13,578
Reaction score
1,032
Points
113
Location
Lubbock, Texas
Website
cyclestopvalves.com
The 50' elevation to the house means you need to add 20 PSI to the pump pressure. So, instead of 40/60 you need a 60/80 pressure switch. Even at that pressure you still only need a 10 gallon size pressure tank when using a CSV like with the PK1A kit. Without the CSV I would use an 86 gallon size pressure tank, which still won't do as good a job as the CSV and small tank.
 

Shad

New Member
Messages
17
Reaction score
3
Points
3
Location
Texas
Someone told me I will burn up my pump with a 1” supply line going 300’ and 50’ uphill. I should increase my supply line to 1-1/4” to 2’’. Is they any true to that? if so what size and would a 1 hp pump still work?
 

Reach4

Well-Known Member
Messages
36,600
Reaction score
3,892
Points
113
Location
IL
http://irrigation.wsu.edu/Content/Calculators/General/Pipeline-Pressure-Loss.php may help with your decision on pipe size. You pressure loss will be the sum of the 50 ft head (about 21 psi) + the dynamic pressure drop due to flow.

If the pressure switch and pressure tank, I would plug 20 gpm into the calculator. You will not have that much flow, but you want to not have a lot off pressure drop in the showers when somebody flushes a toilet or runs the washing machine.

If the pressure tank and pressure switch were up top, I would plug 10 gpm into the calculator.
 

Shad

New Member
Messages
17
Reaction score
3
Points
3
Location
Texas
The 50' elevation to the house means you need to add 20 PSI to the pump pressure. So, instead of 40/60 you need a 60/80 pressure switch. Even at that pressure you still only need a 10 gallon size pressure tank when using a CSV like with the PK1A kit. Without the CSV I would use an 86 gallon size pressure tank, which still won't do as good a job as the CSV and small tank.
Someone told me I will burn up my pump with a 1” supply line going 300’ and 50’ uphill. I should increase my supply line to 1-1/4” to 2’’. Is there any true to that? if so what size line and would a 1 hp pump still work?
 

Fitter30

Well-Known Member
Messages
3,131
Reaction score
506
Points
113
Location
Peace valley missouri
Have any idea what the difference in height is switch to house. 2.31 ' per lb of pressure. 150' rise add 65 lbs to your switch cut in and cut out. Want 40 - 60, 105 - 125. Going to need a different control.,
 

LLigetfa

DIYer, not in the trades
Messages
7,180
Reaction score
477
Points
83
Location
NW Ontario, Canada
Have any idea what the difference in height is switch to house. 2.31 ' per lb of pressure. 150' rise add 65 lbs to your switch cut in and cut out. Want 40 - 60, 105 - 125. Going to need a different control.,
OP said 300 foot run and 50 foot rise. With .43 PSI per foot, that would be a 21.5 PSI drop. That means you need a pump that can produce 21.5 more PSI than the desired PSI at the top of the hill, so if 80 PSI is desired, the pump would need to produce 101.5 PSI. I don't think you will find a jet pump that can do that.

Pressure drop over the 300 feet needs to be calculated based on pipe size and GPM. There are online calculators for that. If inline resistance drops the GPM, the inline resistance will drop since it increases with GPM so as long as the pressure switch cut-out is so high as to drop the GPM to less than 1, it should not dead-head.
 

Reach4

Well-Known Member
Messages
36,600
Reaction score
3,892
Points
113
Location
IL
I was thinking the jet pump was just adding pressure to what the city provides.
 

Reach4

Well-Known Member
Messages
36,600
Reaction score
3,892
Points
113
Location
IL
I was thinking maybe a multi-stage booster centrifugal pump rather than a jet pump. I have no experience with either.

 

Shad

New Member
Messages
17
Reaction score
3
Points
3
Location
Texas
ok Canceled the pump order, still getting the pk1a. Will see if I can get the city pressure tomorrow.
 

Valveman

Cary Austin
Staff member
Messages
13,578
Reaction score
1,032
Points
113
Location
Lubbock, Texas
Website
cyclestopvalves.com
Sorry for the delay. That J15S pump will work fine. Unlike many other jet pumps that one can build 83 PSI max. As long as the city pressure is at least 10 PSI that pump will work fine with a 60/80 switch and a CSV setting of 70 PSI. If you don't have at least 10 PSI coming from the city you will have different problems and will probably require a cistern storage tank.
 

Shad

New Member
Messages
17
Reaction score
3
Points
3
Location
Texas
Measures the pressure before the pump it is 29 psi. What are your recommendations for a pump. The one I have now measured 67psi at the house when it finally kicks on.
 

LLigetfa

DIYer, not in the trades
Messages
7,180
Reaction score
477
Points
83
Location
NW Ontario, Canada
I ordered a 1 1/2hp gourd j15s and a pk1a with a pressure switch 60/80.
That should produce a constant pressure of around 50 PSI, so less than what your current pump produces. Is it a multi-level home or a bungalow? At what elevation is the 67 PSI measured? Remember that you lose .43 PSI per foot of elevation and depending on the pipe diameter, you may also have friction loss.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks