Installing PEX tubing

[Jeremiah D. Seitz]

Hi,

I'm looking to replace my radiators with PEX tubing, but I was
wondering if I had to replace the whole system at once, or I could do
it zone by zone. Is there any reason the two types of systems can't
exist on the same 'circuit'? Pressure requirements, etc?

Thanks in advance,

J.
Jeremiah D. Seitz
Omega Techware
http://www.omegatechware.net

 

[Jeremiah D. Seitz]

If your new tubing is under your floor, and the floor has insulation
value like wood, you might need to run higher temperatures to get the
same heat transfer that you've been getting from radiation directly in
the room. You could always re-balance your zones as needed if they
have appropriate valves.

The floors *are* wood, so your suggestion would probably be necessary.

You might also need a pump with higher pressure capability to force
your fluid through the longer, smaller PEX circuits, but you will need
that anyway so you can install it first.

You've made my evening. Thank you!

Loren

J.
Jeremiah D. Seitz
Omega Techware
http://www.omegatechware.net

 

[[email protected]]

The floors *are* wood, so your suggestion would probably be necessary.

You might put fin-tube under a basement ceiling...

Nick

 

[James Storm]

Hi,

I'm looking to replace my radiators with PEX tubing, but I was
wondering if I had to replace the whole system at once, or I could do
it zone by zone. Is there any reason the two types of systems can't
exist on the same 'circuit'? Pressure requirements, etc?

Thanks in advance,

J.
Jeremiah D. Seitz
Omega Techware
http://www.omegatechware.net

Are you asking about replumbing your existing above floor "radiators"?
Pex I think comes in various grades. Pick the one suitable for heating
water and has an oxygen barrier built in to protect iron and steel
parts. Even closed systems under pressure were getting excesss oxygen
through the pex pipe.
James

 

[Jeremiah D. Seitz]

You might put fin-tube under a basement ceiling...

Is that the copper pipe with aluminum fins, used for (older) baseboard
heating, or something specific to a PEX setup?

Nick

Thanks,

J.
Jeremiah D. Seitz
Omega Techware
http://www.omegatechware.net

 

[Jeremiah D. Seitz]

Are you asking about replumbing your existing above floor "radiators"?
Pex I think comes in various grades. Pick the one suitable for heating
water and has an oxygen barrier built in to protect iron and steel
parts. Even closed systems under pressure were getting excesss oxygen
through the pex pipe.

Pretty much. I wanted to test one or two rooms before going the whole
nine yards.

I think I understand what you mean about the diffusion barrier. I'm
pretty sure that the only iron/steel in the system is the radiators
themselves, but I'll have to check that to be sure.

As it stands, we've got to bleed our system 1-2 times when starting
the system in the fall, and another 2-3 times over the winter. Sounds
like replacing the whole thing is the way to go.

James

Thank you,

J.
Jeremiah D. Seitz
Omega Techware
http://www.omegatechware.net

 

[Jeremiah D. Seitz]

Careful here!! Remember the "advise" you get from these groups is
worth exactly what you pay for it - sometimes much less!

Understood. The grain of salt is firmly in hand at all times. I still
appreciate all responses. Sometimes a consensus isn't as good as a
debate when trying to find the facts.

The "normal" temperature used in your baseboard radiators is 180F.
You do NOT run this high of a temperature for under-floor heating (or
even higher as the previous poster stated). The temperatures for this
run more like 120-140F.

Actually, they're the older 'standup' type - blazing hot close to them
and icy on the other side of the room. So, the operating temperatures
are definitely not compatible, in other words?

UPDATE: According to Radiantec, their 1/2" and 3/8" tubing can handle
temps up to 180 degrees at 100 PSI. Not sure if I want to go that
route, though.

There is a lot of info on the net about radiant floor heating. Check
some of it out before blindly believing everything some poster (myself
included!) writes.

I did scout out some info last year, mainly the Radiantec site, and
learned quite a bit just from their materials. Unfortunately, I don't
recall reading anything about a piecemeal installation like in my
original question.

To be honest, I should have rephrased my question better. I was
wondering if anyone here had actually done it. I was hoping to be able
to test the concept with one room, then make a decision based on the
results.

.....gary

Thankee!

J.
Jeremiah D. Seitz
Omega Techware
http://www.omegatechware.net

 

[[email protected]]

Is that the copper pipe with aluminum fins, used for (older) baseboard
heating, or something specific to a PEX setup?

Copper with fins. Argo Industries sells it for about $2/ft, with a water-air
thermal conductance of about 5 Btu/h-F-ft. It could work very well if warm air
rises up through an interior wall and exits near the ceiling and return air
falls back into the basement via floor registers near outside walls.

Nick

 

[HVAC Guy]

Isin't PEX made by taking aluminum pipe and lining it inside with a
layer of plastic as well as encasing it in a similar layer of plastic
on the outside?

If so, then it would make a very poor heat radiator, given that the
plastic acts as a thermal insulator.

Yes?