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Hot water boiler
johnjohn89
Member Posts: 100
in Plumbing
Boiler experts Question please!
For two story house , boiler in the basement , 8’ for basement, 1st floor about 9’, baseboard radiation about 1’ total 18ft
1’ is for baseboard radiation length or tall? What about if u have multiple baseboard radiation on first floor. Do u need to add 1 ft for each baseboard radiation?
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Comments


Are you asking how much heat or radiators you need?0

@johnjohn89, you're a little incoherent here. Are you asking about boiler fill pressure in feet of head?0

Jamie Hall said:Say what? One foot of what added to what?0

ratio said:@johnjohn89, you're a little incoherent here. Are you asking about boiler fill pressure in feet of head?
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Intplm. said:Are you asking how much heat or radiators you need?
0 

It is based on the distance from the top of the boiler to the highest piping in the system. It is about 2.3 ft for every psi of pressure plus about 4 psi for things like the differential caused by the resistance in the piping and the flow produced by the ciruclator so the standard 12 psig charge and prv setting is good for the highest piping being about 18 ft above the boiler.0

Yes, you need to add the height of the radiator. You want to calculate the height of the highest place water will flow to, which is the top of your highest radiator. So that's the distance from your boiler in the basement to the basement ceiling (8 feet) plus the height of the first floor (9 feet), plus the height of the tallest radiator on the second floor. If you had cast iron radiators, they might be 3 feet tall. But you have baseboard radiators at 1 foot tall, so adding 1 foot height gives you 8+9+1=18 feet total.johnjohn89 said:Do I need add tall of radiator 1ft? If yes why , if no and why? Thanks
Then 18 feet x .43 psi per foot = 8 psi. Then you want to add 5 psi so that you maintain 5 psi at the highest point of the system, so 8 + 5 = 13 psi for your example. That's the minimum pressure you want to maintain.
(You said something about adding a 3 foot ceiling. I think you mean the two floor/ceiling thicknesses added 3 feet total to your height calculation. So if we add 3 feet for the floor/ceiling thicknesses, that's 21 feet, which gives you 14 psi minimum with the 5 psi margin.)
If your expansion tank is already set for 20 psi, you can run your system at 20 psi. You just don't want to go lower than 1314 psi.
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jesmed1 said:
Do I need add tall of radiator 1ft? If yes why , if no and why? Thanks
Yes, you need to add the height of the radiator. You want to calculate the height of the highest place water will flow to, which is the top of your highest radiator. So that's the distance from your boiler in the basement to the basement ceiling (8 feet) plus the height of the first floor (9 feet), plus the height of the tallest radiator on the second floor. If you had cast iron radiators, they might be 3 feet tall. But you have baseboard radiators at 1 foot tall, so adding 1 foot height gives you 8+9+1=18 feet total. Then 18 feet x .43 psi per foot = 8 psi. Then you want to add 5 psi so that you maintain 5 psi at the highest point of the system, so 8 + 5 = 13 psi for your example. That's the minimum pressure you want to maintain. (You said something about adding a 3 foot ceiling. I think you mean the two floor/ceiling thicknesses added 3 feet total to your height calculation. So if we add 3 feet for the floor/ceiling thicknesses, that's 21 feet, which gives you 14 psi minimum with the 5 psi margin.) If your expansion tank is already set for 20 psi, you can run your system at 20 psi. You just don't want to go lower than 1314 psi.2
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