Let the Pex flaming begin

TexasBorderDude · December 19, 2009, 06:10:20 AM

As you might know, I'm adding a Hurricane diesel heating system to my Eagle 05. I couldn't find heat pex, or peanut butter pex either Dallas

, so I am using the standard 180 degree rated pex for the loop from my Hurricane heat exchanger to the front heater coil and the return to the engine. (The engine coolant loop) Since the engine routinely runs at 180 and up to 200+ at times, what can I expect? Has anyone ever used pex for this engine circuit?

Thanks,

dg

WEC4104 · December 19, 2009, 06:30:36 AM

Source for high temp PEX for radiant heating purposes....

http://www.pexsupply.com/PEX-Tubing-223000

dbenck · December 19, 2009, 06:53:13 AM

180 Deg. is the temp/burst rating..your use on engine will have way less
than 100 PSI, Should be fine.

David Benck
Benck Mechanical Inc.

Dreamscape · December 19, 2009, 06:53:59 AM

Hi Doyle!

If you have a Lowes close to Sonnie's place they should have the red 3/4" Pex. It's hot water rated too. Not sure of the temp range, but you might check it out. I'm also not sure of what size you are looking for, I think the cooling loop is around 1 1/4". You might want to use heater hose also, didn't that roll I gave Sonnie work out?

Paul

rv_safetyman · December 19, 2009, 07:05:05 AM

Doyle, I would be a bit concerned about using PEX for the engine circuit. You have to be concerned about not only the coolant temperatures, but also the external temperatures (you will have to route the tubing in areas that are not too far from the exhaust). Also, the engine vibration could be a concern.

If the PEX would let go, you would quickly loose enough coolant to create a situation where engine damage could occur.

I ran the very best heater hose for that circuit. There was a good thread on heater hose and clamps here: http://www.busconversions.com/bbs/index.php?topic=14183.msg150045#msg150045

In that thread I list what I used. Very pricey, but I did not want to cut corners when it comes to the engine area. At least when my engine failed it was not due to a coolant hose

Jim

Ray D · December 19, 2009, 06:53:37 PM

My Hydro Hot installation book recomended to use pex for the fresh water and room heat exchangers and use 3/4" heater hose for connections to the engine, it didn't say why, but that is what I did.

Ray D

gumpy · December 19, 2009, 07:56:56 PM

Quote from: TexasBorderDude on December 19, 2009, 06:10:20 AM
As you might know, I'm adding a Hurricane diesel heating system to my Eagle 05. I couldn't find heat pex, or peanut butter pex either Dallas , so I am using the standard 180 degree rated pex for the loop from my Hurricane heat exchanger to the front heater coil and the return to the engine. (The engine coolant loop) Since the engine routinely runs at 180 and up to 200+ at times, what can I expect? Has anyone ever used pex for this engine circuit?

Thanks,

dg

Yeah, I used it.

I ran it from my Aquahot to a copper line that runs through the tunnel to the engine compartment, and connect it to the engine using 3/4" barrier pex. Been working fine for 2 or 3 years. You want to use a barrier pex design for heating systems, not the fresh water pex. I think mine is still only rated for 180*, but as has been pointed out, that's at 100 psi, which you will never see.

Paso One · December 20, 2009, 04:26:47 AM

There must be quite a safety factory built into the Oxy Pex / barrier pex.

I have it running in another boiler application and the temperature commonly operates in the 180 to 200 * area.

It has done so for 2 years.

Most manufactures build in a safety margin I believe to protect themselves from the idots that say " well you brocheres says "