On Mar 1, 1:28 pm, Freud wrote:
Hi:
We're remodeling the bathroom in our small 1930s house. I'd like to put
radiant heating in to replace the radiator that's there now. From my
reading, I'm thinking of adding loops of oxygen-barrier PEX under the
floor (easily accessible from the unfinished basement) and tying it into
our existing natural gas hot water boiler radiator system. The system is
closed loop with iron pipes and radiators. I was thinking of using heat
spreaders & then insulating below the tubing. Does anyone have any
advice on this? Am I likely to need a tempering valve to reduce the
temperature of the water in the system? Are heat spreaders unnecessary?
Any problems with tying into the iron pipes?

I am no expert but have looked into such a system for my own place.
Most radiant system run a cool 120 degreees F. That doesn't mean you
can't run it at a higher temp you likely can. The pipe will handle it
so the only question is the flooring. What type of flooring do you
have? How hot does your boiler run?

The pipes will be thermostatically controlled so they would have to
cycle on and off more often. Some flooring may not stand up to such
hot pipes or such frequent changes. A mixing valve is not a big deal
from what I understand.

The designs I have seen use the metal spreaders but they are not
necessary. Staples are also available which are just nailed to the
joists. Some people claim that the spreaders make an annoying noise
as they expand and contract. Manufacturers claim they have solved
that problem. If you assume that insulation will be placed into the
joists under the pipes then spreaders seem less of a concern to my
mind.

A manifold is usually used in hydronic setups. This could be as
simple a a tee and a valve which branches off the main line. the
advantage is that an electronicallly controlled valve can be used with
thermostats in the living quarters to have as many different zones as
you wish. If you only want one zone then fine but if you want more
control the hydronic systems are well suited for multiple zones. I
would be cool to have a zone for each room and one for the hallway
too. In Minnesota we heat our houses for 10 months of the year.