Using PEX as return line.

Joey B

I am retrofiting a steam boiler to Hot Water. Will I encounter possible problems by using PEX for my return lines? Can it be use as supply as well?
Some of the pex rating I've seen.
100 PSI Max
200 Degrees
My desing call for 18 psi. and 180 suply 160 return.

Thank you, Any advise is well appreciated.

Ken_40

Go for it!

If the manufacturer rates their product for the application you intend, use it!

Joey B

Joe, Thanks for the encouragement.
Do you know any one that has done it, and worked well?

Brad White_9

We do it


all the time.

I have been using Pex-Al-Pex lately since it doesn't expand as much as regular Pex. Also, regular Pex droops when it gets warm(over 100) and we do not like the look.

PAP stays straight and rigid.

Either product will accomplish what you want.

Mark H

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Cosmo_3

sure but....

Why get rid of the steam? ;-O

As far as pex, I prefer the pex/al/pex. It does not expand as much as straight pex, it will hold a bend, and you can use less fasteners than you would with pex.

Cosmo

Joey B

Thanks Guys.
Nothing is wrong with the steam, it works. But is a 2 family home and one tenant is going through the mid life changes, always hot. While the other have a set of newborn twins. Zoning is a must. Very good tenants.

Steamhead (in transit)

Why not use

thermostatic radiator valves in the hot tenant's area?

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Joey B

I have those installed, but still not working. she opens the windows and they do not close due to the draft. It's a pain

Mark Wolff_2

Pex Usage

We use Wirsbo (insert any brand you like here). The only concern you have is not tying it in within 18" of the tappings on the boiler. Once you have 18" of piping out of the boiler, you can use it for supply and return piping. FYI the same applies for domestic water use tying into a water heater. Code requires fastening at no more than 32" intervals. Plastic 2 hole straps work great. Wirsbo is rated for direct contact with building materials, some others are not, so before installation, read the manufacturers installation recommendations.

Dave Belisle

Pex

We use PEX all the Time in heating loops. I use BK iron or Copper close to the boiler.

Dave in NH

joel_19

yes but

We have run pex as the supply side kept steam pipes for the return. not the other way around so crud from the rads goes into the BIG pipe. Strainer a must on return side before your boiler. I'd also recomend alot colder water than that go with a modcon or add a tekmar nd 4way and trvs on your rads.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mark Wolff_2

cleaning

Additionally, a proper flushing of your system including TSP (tri sodium phosphate) will clear up any crud you have accumulated in the pipes over the years.

Will Merryman

18\" buffer

Mark, Could you elaborate on the 18" distance from boiler tappings ? Is it a heat issue or a safety issue ?

Steamhead (in transit)

That's a tenant problem

not an equipment problem. Unfortunately, it can be hard getting them to listen.....

Try a few Vent-Rite #1 radiator vents. These are adjustable with a thumb wheel on the bottom- without tools- and can be closed off completely so the rads won't heat at all if that's what she wants.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mark Wolff_2

18\" space

Most pex manufacturers require 18" of pipe distance from the heat source (boiler or water heater), their theory being the potential for temperatures above the tubing rating would be greatest in the first 18".

I just had two wisdom teeth pulled today, so the Percoset is making it hard to find the code regarding the water heater connections but I will look in the next day or two.

Kevin M

Pex in radiant baseboard system

I'm installing a hot water baseboard system in an older home. I am planning to use 3/4" pex for the majority of the piping. Can anyone give me some advice about using pex in this application? I see some pex with an oxygen barrier for use in radiant systems. Is this what I want, or is it intended for an underfloor radiant, where the heat is given off by the piping itself? Or is the o2 barrier pex a requirement for all types of hot water radiant even when it is just to supply baseboard heaters? Thanks!

brucewo1b

Pex is great copper replacement tubing

and if you ahve any iron in the system ie steel castiron boiler, expantion tanks circu;ators etc you need the oxygen barrier tubing. Might also want to check out the Pex Al Pex as it holds it shape better and does not expand and sag like regular pex.

Ray Landry

The 18" rule is not because of a heat issue, it's a replacemnt issue. Rigid pipe is a universal fitting which is easily adaptable to, if a type of pex is used that the fitter doing the change out doesnt have then there's problems. 24" is the rule for water heaters.