Honeywell Heat Generator
Mercury Filled Heat Generator for Hot Water Systems

  Do you know what this device is?

Recently we were contacted by the US EPA Region 3 office in Philadelphia about a mercury heating device that left its footprint behind. They had no idea what this contraption was or what it did. But it left its signature of that shiny liquid behind, hence an environmental disaster.

Let me explain this device and its history through my own story, more or less. During my journey toward understanding the older American heating systems, I’ve made my fair share of mistakes. So far, none have managed to put me in the funeral home but came close to it a few times.

Not so long ago, well before we were all terrified of this shiny liquid metal. Mercury was in our toys and our science teachers let us play with it on our desks. It was a liquid that conducted electricity. It was in our thermostats and thermometers. So what could be wrong with mercury (think asbestos)?

Don’t tip a Honeywell heat generator over and spill the shiny metal it creates an environmental nightmare. Read on to see how we got here.

After doing some reading in old heating books my dad had in his library. I learned that Mark Honeywell ( yes, the same Honeywell we know today) invented his heat generator to compete with the folks who were selling steam heat. He was a hot-water plumber, and those steam guys must have been getting to him because their systems ran hotter than gravity hot-water systems and were less expensive to install.

So, along comes this thing called the heat generator. It was a simple device with just one moving part, that being the pint or so of mercury. Honeywell used a pipe within a pipe that dipped into the mercury pot to separate the system water from the water in the attic-mounted, open expansion tank. He could then run the hot water up to about 250° F, while still having a system open to the atmosphere. The super-hot water would circulate much faster, and that was important in the days before Homer Thrush or Bell & Gossett invented the modern-day circulator pump. Honeywell had come up with a brilliant device.

Years later, we still find these mercury-filled time bombs in basements or attics and they continue to tempt the heating trade.

If you’re staring at an odd, old device and you don’t know what it is, put your hands in your pockets and back away from the thing and call us immediately.

The mercury mess of today.

Not so long ago a man (Jeff) in Pennsylvania, whose only crime was he bought a beautiful 1905 house from someone who, was in the Age of Ignorance and left things for the heating system alone. After buying the house about a year later they had to replace their heating boiler for their antique heating system.

Jeff and his wife decided to remodel the attic for his 2 sons bedroom about 5 years ago. They hired a contractor who did a beautiful job remodeling the attic except for the heat generator .

About 3 weeks ago Jeff and his family returned from vacation when he spotted a tiny puddle of mercury over there in the corner of his bedroom. Their bedroom is below their sons bedroom in the attic.

He poked the mercury. It wiggled. He checked online and knew what that shiny stuff was. He washed his hands and called the fire department.

The firefighters showed up and also poked the puddle. They called the chief, who gave it an authoritative poke of his own. Jeff grabbed his family and took them over to his father’s house for the night.

The next day, the Environmental Protection Agency, an emergency response team and some more firefighters showed up, all wearing hazmat suits. They vacuumed for a few hours and then told Jeff , the hazmat-remediation contractor has to finish the job, which was complicated.

The Health Department showed up next and sealed the house. Back to Pop’s for the night.

The hazmat contractors, looking like they were ready to walk on the Moon, started work the next day. They showed a 0.0 ppb for mercury everywhere outside the room with the mercury. So far, so good, but they still wouldn’t let the Jeff’s family return to their house. Hello again, Pop. Mind if me, the wife and kids keep you company?

The days came and went, and the following Monday Jeff sent a letter he received from the hazmat-cleaning company to the County Health Department, who gave the green light for reentry.

They tore down the bedroom ceiling and ripped up the floor. Even the carpet and washer had to go, but they did get to a point where they had gotten it all. The hazmat contractor had to have the hot water heating system cleaned and flush. This where Quinn’s got hired to do this part of the job. They sealed the house for an air test and that went well. Jeff and the gang moved back in. Welcome home.

Care to guess where the mercury had come from?

Come on, yes, you know. Say it out loud, while screaming at the top of your lungs that “Stupid Honeywell Heat Generator” sitting up in the attic. It sat up in the attic hidden in a closet with the open expansion tank, just waiting for the time to arrive along with a heating contractor who would convert the gravity system to a pumped system. Because this contractor has not gone to the library to study, and because he did not know what he was looking at, and because he did not put his hands in his pockets and back away, he did what all of us have done when we were in our own Age of Ignorance. He tipped it and gravity did the rest.

He just let it soak into the floor, oh get some cardboard for the corners so we can sweep “it” up. Hey, it’s just mercury, right? No big deal just like asbestos. You know how that turned out 70 years later.

So how much did this adventure cost? Well, so far it is $48,915 for the cleanup. He still has to pay for the mercury disposal, so that’s an open item. And he had to rebuild the bedroom and attic plus buy a new washer. He figures it will be about $50,000 by the time he’s done.

Well, luckily that’s what the EPA superfund is for in a situation like this. Hum… I still think somebody is going to pay the EPA for this thing. But we will wait and see what happens. I know what you are saying, “ I got homeowner’s insurance they will cover this”, uh…NO! That’s an environmental situation, like the saying goes “SORRY CHARLIE NOT COVERED”.

So, there you are.

We’ve all done some dopey things from time to time. The dangers of mercury were unknown to just about everyone at that time. After all it was an Age of Ignorance. I suppose it all depends on where we happen to be standing in life’s timeline. We’re all ignorant at some point. After all, if it wasn’t for us, a lot of people would die from the cold and the heat.