Two pipe

Paul S_3

Hey everyone...I am doing a oil to gas conversion which involves removing one oil fired hot water boiler and installing two gas boilers....the home has a two pipe system....the customer wants the first and second floor on there own boilers....so I will be removing the steel mains (1"1/2")....and installing 1" copper mains for each floor(1st fl =56,000 btu/5.6gpm)(2nd fl=63,000btu/6.3gpm)..1st fl radiators have 1" pipe going to them...and 2nd floor radiators have 3/4" pipe supplying them.......so basically I will be running the copper mains in 1"....then connecting to the radiators with tee's(1" tee for 1st fl/1"x3/4" tee for 2nd fl)the original steel black pipe leading to radiators will remain......Does this setup seem ok....and if I use this setup would I need some sort of throttling/balancing valve for this to work....I know ball valves are not so good being used for throttling....I really don't want to resort to reverse return because of price of job.....also the size of the pipe supplying and returning from rads can that be changed? Thanks Paul S

Tom_133

Access

Paul



Do you have access to the lines from the radiators individually? I just did a similar job and I ran each radiator individually back to the boiler room and used uponor manifolds to tie them in. It worked very well and the 1/2" Hepex was cheaper then the copper mains and fittings. Just a thought

Paul S_3

yes

I have access to every pipe leading to the radiator.....so you are saying to use a radiant manifold to do this.....should it be piped in reverse return.......and what calculation are you using to figure the size of pipe to radiators? Thanks Paul s

Paul S_3

would

Would this work.....?....example = radiator out put =14,500btu.....20f TD=1.45GPM.... ......so 1/2"pipe would work fine.....I would run half inch pipe to boiler room (14 radiators) and create a two pipe reverse return set up in boiler room using 1"copper.....7 radiators to each boiler? Paul S

Paul S_3

?

Anyone has any insight?

Tom_133

What I meant

Paul



I meant adapting to each 1/2" line with 1/2" hepex and running all back to the boiler

room or in a spot you can access the uponor manifold and feed it with a supply and return

nothing fancy balance it with the manifolds using the flow setters on the manifolds. Very

simple and easy no reverse return needed. You can see this same setup in the uponor install manual.

Paul S_3

two pipe

Tom, the supply and returns leading to the first floor radiators is one inch....and to the second floor are 3/4 pipe....excuse me for asking basic questions but you mean adapt to those line with 1/2"pex then run the pex to the supply and return manifolds in the boiler room? And the manual you are talking about is the uponor radiant heating manual? Thanks Paul s

Tom_133

Paul

I mean if each radiator supply and return directly under the radiator is being fed with 1/2" copper lines to adapt to those and run each radiator individually back to the uponor manifold.

Paul S_3

radiators

I have big column radiators being fed with one inch and three quarter inch lines.....I will be removing the existing Mains seperating the first and second floors of the home on there own boiler...so the pipes leading to radiators will remain....will I be able to use this setup on this job? Paul s

Tom_133

Paul

My job was all 1/2" copper lines that were fed by a 1 1/4 main so it's not the same thing.



I have seen jobs where guys did adapt from 1 down to 1/2" and they did just what I am saying. I would tell you to do the math and see if the 1/2" can support the BTU, and flow needed. A lot of the old houses in my area have radiators that are 3 times to big which is great for getting the water temp down. If yours are oversized than running independent feeds to each may work well for you.

Paul S_3

radiators

I checked all radiators and the largest is 10,000 btu....so of I use universal hydronics formula to find the flow.....10,000 divided by 20TD X 500=1GPM.....1/2" pex will work? Thanks Paul s

Tom_133

Sound good

Paul



The customers I did this for love it. They like the fact that the can zone the radiators with actuators installed on the manifold. It really knocked down the job cost eliminating a lot of copper as well.