Systems Help Center

Our comprehensive HVAC Systems Help Center covers a wide range of HVAC-related topics, including air conditioning and heat pumps, geothermal, hot-water heating, thermostats and controls, solar, steam heating, and warm air. We also have a section of informative and entertaining articles to help you sharpen your HVAC business skills. And our Heating Museum is a captivating journey through the evolution of HVAC technologies. 

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Recent Articles

Freezing Univentilator Coils

I had written a story for Plumbing & Mechanical a while back about a fella in Canada who sent me this email: "Our problem is that five out of hundreds of univentilator co...

Published on 05/08/2023 3:15 PM by Dan Holohan
Posted in Steam Heating
hoffman air vent
Times Change

Morris had me on the phone. It was 1974 and he was calling from Brooklyn, NY. I had a waxed handlebar mustache that year and my workmates at the manufacturers’ rep were c...

Published on 05/08/2023 2:30 PM by Dan Holohan
Posted in The HVAC Business
driving truck
Who's Driving the Truck?

My first job in this business was to be a truck driver for an AC/Refrigeration wholesaler on Long Island. I didn’t have a car at the time, so I walked a mile to the branc...

Published on 05/03/2023 12:46 PM by Dan Holohan
Posted in The HVAC Business
analog guy
Do You Miss the T87?

In 1885, when you could still buy a milk cow for $29.70, Albert Butz, a Swiss immigrant living in St. Paul, Minnesota, invented what he called the damper-flapper. He pate...

Published on 04/27/2023 2:09 PM by Dan Holohan
Posted in The HVAC Business
big idea
What Did You Think Wouldn't Make It?

When we started in 1997, the folks who built that first crude site told me we could have a links page. I asked what that was, and the young man doing the ...

Published on 04/27/2023 2:07 PM by Dan Holohan
Posted in The HVAC Business
Why Congress Has No Windows

People who knew Capt. Montgomery C. Meigs said he was occasionally pompous, but when the job was done to his satisfaction, he said, “This was the most difficult piece of ...

Published on 03/06/2023 1:39 PM
Posted in Heating Museum
near boiler piping
Dry Steam Is The Goal

I love all the advances taking place in the world of hydronics, but I’m still seeing plenty of steam systems out there in our older cities, so knowing about dry steam wil...

Published on 03/01/2023 10:29 AM by Dan Holohan
Posted in Steam Heating
Do Promotions Work?

The promotional offers show up every year and I always wonder whether they work? I suppose some do because the manufacturers repeat them. Buy a bunch of boilers, get a wi...

Published on 02/10/2023 10:43 AM by Dan Holohan
Posted in The HVAC Business
Vent Valve Comparison Chart

This is vent valve comparison chart for balancing steam-heating systems covers the Vent Rite #1, Gorton, Maid O'Mist, and Heat Timer Angle Varivalve. Thank you to Al Piri...

Published on 02/09/2023 4:54 PM by Al Pirigyi
Posted in Steam Heating
Circulators or Zone Valves

Back in my rep days, half a lifetime ago, I sold Bell & Gossett circulators. We didn’t have a viable zone valve available at the time, and when the factory finally showed...

Published on 01/25/2023 1:02 PM by Dan Holohan
Posted in Hot-Water Heating