Thread: Pex clearance

I just read through the Uponor installation instructions, and couldn't find what I was looking for. There's probably some instructions detailing the tubing's distance from baseboard radiators. Anyone know what it is, or where I would find the information?

This stuff is run to the next area right on top of the existing baseboard radiators.

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I believe this, on page 17 of the Uponor installation instructions gives a good answer:

- Do not install Uponor PEX within 6 inches of any gas appliance vents, with the exception of double-wall B-vents, which have a minimum clearance of 1 inch.

- Do not install Uponor PEX within 12 inches of any recessed light fixtures, unless the PEX line is protected with suitable insulation.

Originally Posted by Jim Robinson

I just read through the Uponor installation instructions, and couldn't find what I was looking for. There's probably some instructions detailing the tubing's distance from baseboard radiators. Anyone know what it is, or where I would find the information?

This stuff is run to the next area right on top of the existing baseboard radiators.

It is exposed to the sharp fins and cut outs in the metal. It is lying on the fins of a hot water heating line and it is a blue piece of Pex which is used to distinguish cold water. Last but there are probably another 20 reasons why not but it is just simply foolish and a very lazy way of running a water line.

How about thru the crawl space insulated or thru the attic and down the wall etc etc etc.

No attic or crawl, but they could have cut the sheet rock and fished it through the wall cavity.

JP, I did see that, but it didn't mention anything about radiator clearance. Oh well, I'll play the common sense card on this one.

See page 17 of

http://www.zurn.com/operations/pexrh...sApplGuide.pdf

Says not to scratch material.

Would think that they would show example of PEX run over fin heat as not permitted.

Maybe there's something in the baseboard installation guide that talks about its' minimum clearances??

Thanks for the input. I've let them know that it should be routed through the wall or surface mounted above the heaters (like that will happen).

Jim,
Possible solution, if the PEX was secured from contact with fins.
.

The key is that the heat will weaken the walls of the pipe. As the PEX heats from the heat source(light fixtures included) it will soften and allow the pressure of the water inside the pipe to stretch the pipe. This thins the walls to the point that it could burst or even a small previously unseen scratch in the PEX could leak.

I can understand the pex should be supported away from the fins but the question I have is if the pipe is rated for the temperature of water in that system the radiated heat from the heater could not get it any hotter than the water in the system already does?

Originally Posted by paul hardy

I can understand the pex should be supported away from the fins but the question I have is if the pipe is rated for the temperature of water in that system the radiated heat from the heater could not get it any hotter than the water in the system already does?

Bingo! The threat is not heat but it MAY be the fins of element. There will be significant expansion and contraction of the element rubbing against the PEX which in time may, and I stress may, be cause for concern.

Originally Posted by Rod Butler

Bingo! The threat is not heat but it MAY be the fins of element. There will be significant expansion and contraction of the element rubbing against the PEX which in time may, and I stress may, be cause for concern.

Scott may be right depending on the actual PEX that was used. Not all PEX is created equal.

PEX comes in three colors, and as far as I know, there is no requirement to color code. Sure, we normally assume blue is cold and red is hot, but they don't HAVE to be.

It wasn't blue. It was the translucent PEX for non-potable use.

Originally Posted by Garry Sorrells

Scott may be right depending on the actual PEX that was used. Not all PEX is created equal.

I agree Scott is correct about heat from a light fixture but the threat of heat from a finned radiator element is NOT a threat.

Originally Posted by Rod Butler

I agree Scott is correct about heat from a light fixture but the threat of heat from a finned radiator element is NOT a threat.

<Sigh> Thermal expansion and contraction, abrasion, and a failure to support, protect, and compensate for same are indeed factors. This is why we don't run directly through holes in metal studs without protection, and provide for movement in runs.

Not all pex is rated for continuous or frequent exposure to temperature ranges encountered in every hyrdronic heating system. Not all pex tube is designed to be used in hydronic heating systems. Most pex is to be protected from ambient light and UV exposure, this includes light from above via those fully open in heating season convector covers.

Originally Posted by H.G. Watson, Sr.

<Sigh> Thermal expansion and contraction, abrasion, and a failure to support, protect, and compensate for same are indeed factors. This is why we don't run directly through holes in metal studs without protection, and provide for movement in runs.

Not all pex is rated for continuous or frequent exposure to temperature ranges encountered in every hyrdronic heating system. Not all pex tube is designed to be used in hydronic heating systems. Most pex is to be protected from ambient light and UV exposure, this includes light from above via those fully open in heating season convector covers.

As I stated: The threat of HEAT from the finned element is NOT a threat.

I realize your desire to pontificate dictates that you see and not read the previous posts.

The heat from the heater to me does not seem to be an issue, however the fins could be a problem in the long run due to vibration over time. anytime there is something sharp and close to pex it is best to deal with it properly.

The return for the hydronic is the cold side of the loop (pex).The copper tube supplied fins HEAT will affect thermal expansion of the PEX before the cooler hydronic fluid (water or mixture) flows within it. The fluid flowing through the cold side return loop within the PEX would be of a LOWER TEMPERATURE than that which flows through the copper tube.The heat from water flowing through copper tube is much more readily transfered than that which flows through pex.Thus the HEAT from the copper and the fins IS a factor to be considered.I am aware of at least five and likely more colors of pex tube. Natural, red, blue, clear, and a purple and/or black. "Vibration"?!? it is movement caused by thermal expansion and contraction, this affects length and to a nominal degree diameter, and a tendancy to change direction or return to a natural spiral/coil. If it is vibrating, or pulsing, that would be different problem entirely.

Bill,

Were there any designation markings on the PEX that would give a clue to it's maker? If so, you need to determine, as others have said, what type of PEX you are dealing with. This will tell you how this needs to be approached. To make the assumption that only the contact with fins (abrasion) needs to be dealt with is the wrong thinking.

Do as others have suggested and find out what material you are dealing with here. Then make your approach. If you are dealing with a Client then do all of the above.

Originally Posted by Mitchell Toelle

Bill,

Were there any designation markings on the PEX that would give a clue to it's maker? If so, you need to determine, as others have said, what type of PEX you are dealing with. This will tell you how this needs to be approached. To make the assumption that only the contact with fins (abrasion) needs to be dealt with is the wrong thinking.

Do as others have suggested and find out what material you are dealing with here. Then make your approach. If you are dealing with a Client then do all of the above.

You make an interesting point but I believe the OP indicated the brand was Uponor, that may have been an assumption. If the PEX is the wrong material for the hot water system then there may be a problem with heat, but that problem is NOT the heat from the finned element but the heat from the water itself.

If the PEX is the correct for a hot water heating system then the heat from the element will have absolutley ZERO adverse effect on the tubing. Doesn't matter if the tube is supply or return which BTW was not indicated in the original post.

Placement of the tubing within the cabinet (top side or bottom side) may have some adverse effect on the element's heating capacity but that is very minimal. In the 2% to 3% range I think.

Its possible to slip insulation over the tubing to protect it from physical detriment the tubing will slide and expand and contract within the insulation,then again there is always the question if oxygen barrier tubing was needed.