Hooking up Pex pipe? Have questions... Please help.

[Doyle670]

So I have large house, costs a fortune to heat with fuel oil. Therefore for the last couple years i've used the indoor wood boiler that sits in the basement right next to the furnace. It works great. I use about 12 cords of wood from October-March while burning 0 gallons of fuel oil, then burn approximately 200-300 gallons of fuel oil from March-October.


Although it is nice having the wood boiler in the basement(can load it in my underwear, with no shoes on, etc.), it also is a pain with the smoke and actually getting the wood in the basement. Every now and then when the stove needs to be cleaned it will start smoking pretty good when the door is open to put more wood in. This of course travels right upstairs and usually happens at the worst time(11:00pm on a monday night 5 degrees outside) and can't be cleaned instantly. It is bearable in the house, but just a real nuisance.

So here is my plan. I have an attached 2 car garage that currently has a massive wood stove in it. I want to move the indoor wood boiler to the garage in place of the massive wood stove. In doing so I have to run the supply and return lines to the wood boiler in the garage from the furnace in the basement. It is 49' and I need 2 lines so 100' of pex/copper/cpvc will be enough.

At this point I am preferring pex over copper(because of price - $1600 copper $650 pex) and cpvc(because of many peoples advice). The copper lines that hook to the wood boiler currently are
1-5/8"OD and 1-1/2"ID.

So my first question. I assume I would need to at least stay 1-1/2"ID with the pex I use? So i'm looking at 2" pex that has an inside diameter of 1-5/8". If I go with 1-1/2" pex the inside diameter will be a fraction under 1-1/4"(quite a bit smaller than the current ID of the copper).

Also second question. To connect the pex to the copper, I can simply slide the pex over the copper pipe stub at both locations. But what should I use to clamp/crimp it? I was looking at pex clamps/crimps, but cannot find any clamps that go big enough to use on 2" pex line.

I will probably have some other questions regarding circulator placement for the wood boiler(leave where it is or move near the wood boilder in the garage), but will ask them at a later time. Any help is greatly appreciated by both myself and my "sick of smoke" wife.

 

[Jadnashua]

What temps do you run the boiler at? There are some limits on how hot you can run it with pex, and since it is relatively uncontrolled, pex may not be the answer (most pex is not recommended above 180-degrees). You won't get a good seal by just sliding it over copper. There are a couple of ways to connect pex to copper: a compression fitting (requires an internal support ferrule in the pex), and a crimped fitting. While they probably make them, I've only seen the crimped fittings for 1/2 and 3/4" pex. To use a crimped fitting, you'd need to solder on a fitting to the copper, then slide the pex over that, and crimp it. The fitting will have some barbs or ridges on it; you crimp it between those. On a big pipe like that, it may be a challenge to insert the pex (no idea, since I've never used any that large).

CPVC may also have some limits on max temp...you'll want to review those carefully. You may end up with copper anyway.

 

[Sponsor]

 

[Doyle670]

I run temps at 160-165. And it is pretty safe because the cirulator kicks on at 160 degrees and if it rises above 165 it kicks off a modine unit that is a dump zone. So I am comfortable with the temps to run pex. I just can't seem to find a way to connect it to copper. I can put a pex connector fitting soldered to the copper but I can't find them that big.

Which doesn't make sense, if they sell pex that big, they would have to sell connectors that big right?

And I definitely won't be able to afford the copper. If I go the copper route along with the rest of my project, I might better buy an outdoor wood boiler.

 

[Jadnashua]

This fitting may work, and there may be others on this website that can as well. WHen you get to these larger sizes, they do get expensive. Note, that this is designed for Uphonor pex, I assume, but you'd want to check, that it would work on other brands. They sell multiple brands, and I didn't look that closely. Also, for heating purposes, you want a pex designed for heating systems, not one for potable water...it should have an oxygen barrier, which makes the pex more expensive. Using potable water pex will allow oxygen to get into the water and corrode the boiler and fittings. http://www.pexsupply.com/Wirsbo-Uponor-5550020-WIPEX-Fitting-2-PEX-x-2-NPT

Hope this helps...

 

[Doyle670]

Thanks they will definitely work. I was actually looking to use the Uponor hepex with oxygen barrier anyways, so these fittings will do the job.

Plus this combo will give me a max temp allowed of 200 degrees. Even at $70/piece, it will still be way cheaper then using copper.

Now for the next question. The supply line going from wood boiler to furnace currently has a circulator in it. This is currently located between the wood boiler and furnace with the boiler and furnace being about 5 feet apart. If I move the wood boiler so that it is 45' away from the furnace where is the best place to have the circulator? Closer to the wood boiler or closer to the furnace? Do you see any issues with this far of a distance? I know there are other people out there that have their wood boilers many feet from the furnace, but i'm not sure if they've had to upgrade their cirulators.

As a note, this circulator is controlled by temperature switch on the wood boiler. When the water reaches a certain degree, this circulator kicks on. So if I keep it near the furnace I will have to run a wire from the circulator the 45' to the temperature switch on the wood boiler.

Thanks again.

 

[Tom Sawyer]

You need to run heat pex if you run pex at all. Heat pex has an oxygent barrier. Second, 1 1/2 or 1 1/4" pex is a bear to work with and the tools to work it are very very expensive. Go copper.