PSA: Thermal fluids can wreak havoc on hoses (yes, even OEM supplied ones!)

Thought I’d put this out there because knowing ahead of time could have saved us a chunk of money.

We currently run a Fluid Chillers AIR-ULT unit that we took delivery of last August for cooling our bulk ethanol and some jacketed reactors. I like Fluid Chillers, I think they make a great product at a reasonable price and their service tech for our region is a sharp guy I’ve spoken to a few times. Outside of this current hickup this machine has been a hard worker and quite reliable.

When we purchased this unit we bought Dynalene HF-LO thermal fluid as we were advised to in order to maintain the warranty, since this machine was just shy of $60k by itself (not including thermal fluid, lines, fittings or the vessels it connects to) that seemed like a reasonable thing to do, even though I wince at the cost of a 55 gal drum of Dynalane.

Lately we’d been noticing that the fluid level was dropping though no obvious external leaks. I spoke to fluid chillers tech and after some back and forth, was able to get some compatible dye drop shipped so we could have an easier time spotting any potential leaks as the HF-LO fluid is clear and evaporates rather quickly at ambient temps, especially at the altitudes along the front range.

Before the dye showed, we saw the fluid level drop significantly again and FINALLY had a leak we could spot and feel under a piece of insulation where a flexible silicone hose made a bend. The pictures tell the rest, even though this hose has a steel wire reinforcement that was bent from the factory, the exposure to the HF-LO thermal fluid has caused swelling and significant degradation - a measurement at the hose end after the hose was removed from the barbs at the end found it had expanded from 1" ID to over 1 3/16" ID.

Temporarily, we made up a segment using tri-clamp parts to bend the corner and go in between the pictured section that was cut out, until some new hose and barbs arrive from the manufacturer. To Fluid Chillers credit, they say they now have a new hose supplier with a hose that is supposed to be even more resilient to exposure to this thermal fluid, but I estimate the difficult to diagnose leak has cost me hundreds of dollars in expensive thermal fluid as well as time trying to locate the leak.

So - PSA - dye your clear thermal fluids BEFORE you have a problem, and if your chiller uses silicone based hoses and petroleum based thermal fluids, doing periodic inspections under the insulation wraps isn’t a bad idea.

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Well there’s not much to say “To their credit” unless they are paying for everything to be fixed. You specifically went with that fluid because of their demands, and the damage is a direct result of their requirements… I just hope that they took care of something, if not everything

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They definitely need to pay for everything if they recommended it

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Yeah dude, if you have email correspondence that shows they recommended those hoses with that fluid you should demand a new set of everything.

Fucking crazy that they wouldn’t double check that for a $60k chiller :upside_down_face:

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