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@jesmed1 Thats some good detective work Its rarely one issue Its usually from years of someone tinkering

Thanks for that video, Ray. When I began maintaining the heating system in our 4-unit condo building with 2 Weil-McLain WGO-5 boilers and original gravity-conversion hot water radiators, I realized both boilers were short-cycling.

Your title "Boiler Room Retective" is very apt, because some of the reasons for the short-cycling were not obvious and took some sleuthing. The one that took me longest to figure out was the improper placement of both thermostats. The installer had conveniently run the thermostat wires inside one of the chases where hot water risers go up to the second floor. So of course, the thermostat got installed on the wall right at that chase location. When the heat came on, the riser heated the wall behind the thermostat, causing it to satisfy before the room reached the setpoint temp. That took an IR gun to figure out. The other factors were more obvious.

In the end, we had 4 factors contributing to short cycling:

1. Oversized boilers (4x actual building heat loss at design day temps)
2. Thermostat left on factory default setting for forced hot air, which resulted in too small a differential
3. Thermostat improperly positioned on internally heated wall
4. Draft inside wall blowing air into back of thermostat (fixed by foaming entry hole around Tstat wire)

The hardest problems to solve are the ones where you start with the default assumption that there's only one cause, only to find that you were wrong, and there's actually 2, 3, 4, or more contributing factors. I expect you've seen a lot of those in your career.

Boiler short cycling is bad I've been told my entire career but they never explained how to identify short cycling and why its bad. This video helps you identity short cycling, why its bad, and how to remedy or at least reduced it.

had coffee without caleffi today for the first time in a few daze cause i'm home, but look what @hot_rod cooked up besides the cappucino. convert from multiple pumps to multiple zone valves:

albeit coolest find of the show because of my interest in flammable refrigerants was spacepak R290 5 ton chiller style heat pump. still waiting to get the COP curves but 167deg F out. once they get me a cut sheet and availabilities i'll post.

they recommend 35% 1,2 propanediol (PG) for burst vs freeze protection since you are going to be in heat mode enough to keep it from slushing anyway unless something goes wrong in which case you want to protect against burst because of the portion of the hydronic circuit that is outside (although 1,3 propanediol (PDO) has lower viscosity. a little harder to find a direct specific heat comparison although AI says the thermal properities of PDO are superious. it's more expensive albeit less toxic. I wish I had spent more time at a few chemistry booths although we got installer show at javitts and eastern energy at mohegan sun coming up. don't know how many chemists will be at those.

I'm really impressed although i'll be even more impressed when they start using the lowest pressure isomers like isopentane because I think with the lower pressures you could even more easily make service compenents with isolation and modular unions that wouldn't be subject to leaks in the comparatively lower operating pressures. but guy at booth (damnation thought i got his card) said they didn't want to be too exotic seeming and propane has bigger installed base at the moment. true isopentane is more expensive but we're talking $400 for a metric ton of propane, $1300 for a metric ton of isopentane and $55,000 for a metric ton of R32- just sayin'.

brian

When you are prepping to teach you revisit the trusty beginnings (at least it was for me 20 years ago).