Heating Help

Bray oil fume

Hi:
I have an older solar space heat system using Bray oil as the working fluid. (An antifreeze/anti-corrosion water mixture is the storage medium.)  I have a leak somewhere and have noticed a slight "hot engine" odor lately (several months now). Is this the Bray oil or the tank fluid? What is it's health effect? How much should I be worried?  Thanks for considering this.

Possible leak in old system

I am not familiar with the specifics of "Bray Oil", but if your odor smells like an overheated car, I would guess that it contains ethylene glycol and some corrosion inhibitors.  Ethylene glycol is toxic to humans if ingested or inhaled as a aerosol (spray mist).  It is very toxic to cats and dogs. My thoughts are that the corrosion inhibitors have failed, and that a metal fitting somewhere may be leaking, or a pipe or tube may have failed.  I suggest you find the leak, or get a pro in to find it ,and repair it immediately.  Solar systems need routine maintenance, and some of the older systems may have reaching the end of their usefulness. 

Possible leak in old system

I am not familiar with the specifics of "Bray Oil", but if your odor smells like an overheated car, I would guess that it contains ethylene glycol and some corrosion inhibitors.  Ethylene glycol is toxic to humans if ingested or inhaled as a aerosol (spray mist).  It is very toxic to cats and dogs. My thoughts are that the corrosion inhibitors have failed, and that a metal fitting somewhere may be leaking, or a pipe or tube may have failed.  I suggest you find the leak, or get a pro in to find it ,and repair it immediately.  Solar systems need routine maintenance, and some of the older systems may have reaching the end of their usefulness. 

Bray oil fume

I'm not up on Bray oil either, but I do know it's a high temp hydralic fluid -developed for the space shuttle- and I can't identify any particular odor. I've also gazed at the heat transfer tank and smelled nothing, nor have I seen any sheen on it's contents. The heat storage tank is 400 gallons of water with a "corrosion inhibitor" added. The tank is filled with clear green liquid, open to he basement through a pressure release stand pipe. 

Odor issue with solar heating

I was going to advise you to post your questions on the "Solar" thread on this website, and I see that you already have.  Possibly you are smelling the fluid you describe as "clear green" like most automotive anti-freeze is, from the atmospheric vent in the basement. There is no sniffer that would detect ethylene glycol, but any lab could tell you what's in that fluid.