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cracklin audio · Dec 25, 2008, 03:20 PM

I have an existing boiler with radiant heating in the first and second floor of my house.
I am in the process of installing radiant(PEX) hot water heating in the floor of my basement. I want to control the basement separately from the rest of the house, i.e.. Two thermostats. How is this done?
Can someone lead me in the right direction?

Thank you
Cracklin Audio

KC13 · Dec 25, 2008, 03:25 PM

Install a separate pump and control system (relay, thermostat) for the add-on. Does your boiler have sufficient capacity for the increased load?

mygirlsdad77 · Dec 25, 2008, 05:44 PM

You could also add zone valves. Will still need to add extra control box, either way. When you say radiant heat upstairs, do you mean basboard? If so, you will need to add a tempering(mixing) valve to lower water temp for the floor heat. Do not want to run 180-190 in floor, should be between 120 and 140 for floor, and baseboard will require 180-190.

hvac1000 · Dec 25, 2008, 06:44 PM

All PEX tube is not created equally. Make sure the tube you purchase is classified for the type/style of usage. Some PEX is not listed to be used with and ferrous metals and iron while other PEX can be used with CL-TD and CL-R setups. Besids the cost difference there are performance issues that must be delt with between the different types. Many homeowners adding to there system do not know the difference so I thought I would mention this fact to help you prevent future problems. All PEX and system layouts are not created equally so do your research and get it done correctly the first time because once completed it is a real bear to redo. Merry Christmas.

mygirlsdad77 · Dec 25, 2008, 07:28 PM

Hvac mentioned very critical info. There is more to this than meets the eye. I would suggest talking with some local plumbing/heating contractors and get the job done right. Im not saying you have to hire the contractor, just make sure you have the correct info and support to continue the job.

You may be able to lay the pipe in the floor, but I would think twice about the repiping of boiler system by yourself.

cracklin audio · Dec 27, 2008, 09:02 AM

Hi All.
This is cracklin again.
Thanks to all who responded.
The pex that I have is rated for "O2". 100psi@180F.(Red)
I am not planning on repiping my existing boiler, just tapping
Into it with a proper Rehau manifold and mixing valve to lower the
Temperature.
I'm planning on installing a sensor in the slab so I can have two tstats.
I'll try to do as much of it as I can and call an expert to finish it off.

Thanks
Cracklin

hvac1000 · Dec 27, 2008, 10:19 AM

Good luck.

mygirlsdad77 · Dec 28, 2008, 04:28 PM

Sounds like your on the right track, please keep up posted on how things turn out. Take care

Lee

EPMiller · Dec 28, 2008, 08:56 PM

Originally Posted by cracklin audio

<snip>The pex that I have is rated for "O2". 100psi@180F.(Red)<snip>

Without knowing which brand of pex you are looking at, I will just add make certain that it has an oxygen barrier, maybe that "O2" refers to that. The stuff we use is labeled hPex and says it is NOT for potable water use. I had a neighbor that had to replace most of a furnace because he used regular water supply pex for his delivery system. It only took 10 years for that to happen too.