Figuring drop in gas line in WC

Jeeper350 · May 12, 2016

Trying to figure out what size of gas line I will need to run for my house and was curious how you figure out pressure drop in water column... is it standard in certain areas? Or do you have to use a manometer and measure it?

frodo · May 13, 2016

if this doesnt help you out

we could do it another way

to figure out gas size, you take the determined length and the btu' rating

i have a chart that does all the voodoo

on a simple residental house with w/h, heat unit, dryer, fp
1'' to the w/h and heat
3/4 to dryer
1/2 to fb

Jeeper350 · May 13, 2016

Thank you frodo, i want to feed a possibly 199,000 btu tankless at a point
-from meter to it about 140'
-then t off that at about the 90' mark to another smaller tankless on other side of house which would be 170' from T or 260' from meter.
-at about 60' from the T going to smaller tankless I need a T to feed a outdoor grill and maybe some small gas powered lamps
-and eventually i would split off one of those tankless to feed a gas range..
Reason for 2 tankless is my house is really long and distance from furthest in house bathrooms is 140' also installing a outdoor shower thats probably another75 foot farther plus a outdoor sink at outdoor kitchen area. So i have 3 full baths now plus the oudoor area, and in future may add a master suite bathroom with large tub.

- right now from meter to 90' mark where first T will be is 1.25" inch ips yellow pe pipe. Worried i may need to start from meter with 1.5"

- I am fixing to pour some patio areas and need the pipe to go under them and a couple through them, so was thinking i could run 2.5 or 3" grey conduit to allow me to run it under them after they are poured.. and using 3" grey pvc els to allow flexible riser to poke though slabs..?

Thanks for any help and advice.

frodo · May 13, 2016

run 1.4 to the first tee at 90'

Jeeper350 · May 13, 2016

Sweet man.. thanks. Does it matter if the stove top in kitchen comes off end of the longest run to smaller tankless (unit on your diagram). That would be straightest shot to it.. other wise would have to go from 199,000 btu unit to it. And think that would be a longer run.
-also is it ok to run it through say 3" conduit under the two porches.. one would be a 12 foot run the other 24 foot.

frodo · May 13, 2016

if you install a conduit....use 2, 45 instead of a 90. and install a pull string in the pipe as you put it in

or train a mouse to go fetch it later

in the note.....it says if you add a stove, that line needs to be 1''

if you want the stove at the end of the line.

run 1'' to the heater then 3/4 to stove