2 Pipe Steam - improving efficiency & eliminate short cycle

V8toilet_3

I can tell you that Adaptive thermostats do work with steam systems especially when you have the venting set up right. Have had one on my one pipe steam system for over two years now and it works great. Keeps the temperature withing 1 degree in the room with the thermostat and 3 degrees for all the rest of the rooms depending on how well you balance the system. Just make sure you get one that learns both run time and automatically anticipates for the overshoot. I bought a Honeywell RTH7400.

Gary Segal

2 Pipe Steam - improving efficiency & eliminate short cycle

Hello experts, first, I want to thank everyone for your past help! Based on suggestions from The Wall, studying "The Lost Art ...", and from service by Steamhead, we have reduced fuel consumption from an average of .16 gal/degree day in the 2001 heating season down to .105 gal/degree day last year. Changes included installing a Vaporstat, downfiring the boiler (it is oversized), replacing all radiator traps, and improving end of main venting. So this year, I would like to make further improvements. Here is where I'm at:
1. Short cycling continues to be an issue. Part of the problem is our programmable thermostat, which does not cut out until 2 degrees over setpoint, meaning that one burn raises the temperature less than one thermostat cycle. Any recommendations on thermostats? Will Adaptive thermostats work OK with steam? The house is empty much of the day, so, based on what I have read, it would be great if we could step the temperature up when needed by a 2 -3 good burns.
2. Also on the subject of short cycling, there were some excellent suggestions last year ( see http://forums.invision.net/Index.cfm?CFApp=2&Message_ID=292694)to dispose of the old air eliminator (see picture), which I have not yet executed. I did not want to try too much at once, but now I am ready. The concern last year was that the return may not be adequately vented to optimize flow rate to the radiators. Any new thoughts? The bottom line is that with a 1.5 psi cut out and a .5 psi differential, the boiler is only off for about 30 -45 seconds before firing back up.
3. I increased main line venting using a medley of vents (one Gorton, one Hoffman and a thermostatic trap to the return). I vented this way, because I had all the parts on hand and it seems to work OK (see picture). There is no steam in the return piping. However, given that the vents are all at the end of the main and given that the main is 80 feet long (with seven 90's and one 45), I was wondering whether it might be beneficial to tap into the main before the ends and add some additional venting.

Thanks in advance,

Gary

Steamhead (in transit)

That looks awfully familiar ;-)

check your e-mail, Gary.

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Gary Segal

adaptive thermostats with steam

Thanks for the advice. I just bought a Honeywell 8000 series and hope to set it up tomorrow.

Gary