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Re: Weil-McLain EG/H: thermostat and pressuretrol shut the damper, but not the spill switch.

Seems that both dampers work off the same external wiring. 1 constant hot, 1 common, 1 call for heat and 1 to power ignition so I guess the dampers could be interchangeable. Don't know if the plugs match.

I noticed the LEds in series as well.

EBEBRATT-Ed

Re: Can a new steam system be installed in a new residential house?

George at Harry Cooper Supply in Missouri would do heat cool loads and duct design for residential jobs. He had a drawer full of old cardboard slide rules :) did everything long hand!

But I wonder how many of his designs got purchased and installed as designed. The low bidder, or know it all contractors, tend to value engineer HVAC jobs

hot_rod

Re: Radiant Heat. Should I raise the temp?

I have to disagree with Eds statement here :)

Screenshot 2025-12-07 at 11.55.41 AM.png

Truth is Higher flow, tighter delta= higher AWT = hotter overall heat emitter = higher BTU output. You cant cheat the laws of thermodynamics

1 Hot goes to cold always

2 The rate of heat exchanges is based on the ∆. Hotter emitters in a room that is of any lower temperature increases the heat output.

Various ways to get there.

Heat exchangers that we maximize transfer from run tight ∆. Solar thermal we look for 3-5°. We want heat in the tank as fast as possible the avoid loss to the ambient.

Plate heat exchangers can design to "close approach" temperature with 3° with high flow rates.

Every single heat output chart you find for any heat emitter shows a selection of flow rates ∆s to see output differences.

Putting a fan behind a finned water coils (forced convection) "speeds up" the air movement, "speeds up" the heat output. It works on both fluids and air.

Google this article.

Screenshot 2025-12-07 at 11.50.29 AM.png

Floor coverings limit the amount of BTUs you can deliver. Base slabs, tile floors, and hard surface you want to keep around 82° surface. 82-70 X 2 = 24 btu/sq ft as a reasonable heat delivery. Colder ambient increases output 82-65 X 2 =34 btu/ sq ft. That may be fine in a work shop, but 65 ambient is a bit cold for my home :)

Perhaps the first part of a loop is a bit higher surface, above 82° it dissipates as it travels. The AWT tells more of a story.

It is easier and more linear to increase heat output by increasing SWT- AWT, instead of flow increases..

You cannot "fix" a delta T in a system, it goes where nature takes it! Trying to fix or "constrain" a ∆ is basically putting the brakes on the system. Loads are dynamic in a home, building, let your hydronic system also be dynamic, it will find thermal equilibrium if you don't screw it up :)

If you are a just a bit short, a few degrees try upping the SWT 5° first. You have the ability to do that without any component changes.

hot_rod