T Rise Differential??? What is it?

Hinman

Single pipe steam boiler servicing 12 apartments, 3 stories. What is a T Rise on the control panel? What does T Rise do? What should it be set to? Currently it’s at 1. What should the Pressurtrol be set to(guessing that’s what the Honeywell thing is in the attached pics) Seems that the Pressuretrol is set close to 1. What variables determine if I want to lower or raise the T Rise or have found the sweet spot? What variables determine if I want to raise or lower the Pressuretrol or have found the sweet spot? Also noticed a sensor temperature limit, how should I use that? There are two apartments that get 5 degrees hotter than the rest upward of 79 degrees. Pics are attached. Thanks!

Jamie Hall

T Rise is, almost certainly, the "swing" setting -- that is, how many degrees difference between on and off on the temperature sensors. Smaller swing would give you shorter cycles, but -- provided the cycles were long enough for steam to reach all the radiators -- tighter temperature control.

The pressuretrol looks as though it's set as low as it can safely go. Leave it there. Low pressure almost always works better. There are exceptions -- but I doubt that yours is one of them.

The two apartments which get too hot might be cured by reducing the speed of the vents on their radiators -- assuming that the main venting is adequate in the first place.

Hinman

> @Jamie Hall
Thanks for the info! Makes sense now. Regarding the Pressuretrol what do you mean by “safely”?

Jamie Hall

By safely on the pressuretrol I mean that there is a blessed little spring inside the thing which has a way of coming undone if you try to crank it down to far. This you do not want to have happen...

You don't mention maintenance at all. It is not uncommon for the little pipe which connects the pressuretrol to the boiler -- called a pigtail -- to get clogged. If it does, the pressuretrol won't see the boiler pressure, which can run higher than you want it. When you have the boiler maintained, by might ask to have that checked.

Hinman

@Jamie Hall thanks Jamie! You’re the man! That all makes sense. Honestly I’ve never maintained the Pressuretrol. I’m guessing it can’t be too hard to take apart myself and clean it before the heating season? Any parts in it that should be replaced?

Jamie Hall

Don't take the pressuretrol apart -- just take it off the boiler and make sure the pipe into the boiler is clear.

You may have to open the cover and disconnect the wires to take it off the boiler (turn off the power!!!) but that's all, and just make sure they are connected back the same way.

Hinman

@Jamie Hall thanks for the instructions. I’ll do that. The water is dirty as hell so I’m sure it can use a cleaning.