Choices about Zones and offsets

tcnjdeluca

I am writing to ask for advice on how to deal with the steam heating zones on my house. I would like to start by saying I plan on brining a knowledgeable professional to maintain and update my system before the next heating season but I am wondering what to do about the rest of this season.

I have a home with an attached office. The home is about 3000 square feet and the office is about 800 square feet give or take. They are separate zones of a 2 pipe steam system. Each zone was controlled by a large motorized valve in the boiler room. Last week the motor for the valve on the main house failed (heat either being stuck on or off depending on its mood), being in the middle of the holiday week I had to get the heat working myself. I opened the valve and bypassed it now the main house is always open to the boiler and controlled by a thermostat in the main house. The valve and thermostat on the office still worked as they once did.

My wife sees clients in her office about 4 hours a day. In the past she had always used large offsets since for 20 hours a day the office sits empty. She kept the office around 58 and would turn it up to 66 if clients where coming in. This worked okay, but the office did suffer from pretty bad water hammer at times. With the house always open to the boiler the large offset is not working as the house gets too hot as the office heats up. I have raised the temperature in the office to about 62 in the office for now. My wife has used a combination of short periods of steam heat and a space heater to make her clients comfortable over the last week.

I should add that all water hammer has stoped, I guess since the large boiler is no longer heating up a small office by itself. The heat loss between the 2 zones seems pretty even. The office thermostat seems to be basically controlling the entire house, which is maintaining a fairly even temperature. Although the boiler does seem to be short cycling a bit. It has been fairly mild weather.

Okay sorry for the long preamble, the way I see it I have some options and I don’t know which one is best in terms of efficiency and my systems health.

1. Find a replacement motor for the valve (been having trouble finding it) and return it to the old set up water hammer and all.
2. Leave it the way it is now with the office thermostat heating up the house.
3. Bring the temperature of the office and the house up to our preferred temperature, run the boiler from the main house thermostat, leaving the valve in the office to close if it gets too warm.
4. Something else I have not even thought about.

Thanks as always.

EBEBRATT-Ed

#3 seems like it will work at least for now. Look at "find a contractor on this site"

You don't need just anyone, you need a steam professional and there aren't that many around.

You may not need the zone valve at all. But that's for your steam expert to decide.

Where are you located??

luketheplumber

don't bother with zones on a steam system there in no point you will still burn the same amount o fuel it just causes problems

tcnjdeluca

Located in central NJ near Trenton. I have not found an expert local but there are a few recommended pros from this site about 45 minutes away. I will definitely have one out soon.

Jamie Hall

Has there been another thread which was nearly identical, at least as to situation? Seems to me... but my memory isn't what it once was.

To address this one. Zoning steam can be problematic, as to function well the boiler needs to be reasonably closely sized to match the connected radiation.

So a first question: what is the EDR rating of your boiler, and what are the EDR ratings of the two zones, taken separately? The answer as to the best way to proceed depends somewhat on that.

The water hammer almost certainly has to do with incorrect piping for the zones -- and since it is associated with the small office zone, with that zone. While not always a sure cure, it is still a necessary partial step: all zone valves must be full port. Further, they must have drips to a cold return on both sides of the valve, as close as possible to the valve. These drips are in addition to any drips which may be needed if the valves were considered to not be there. Close attention must be paid to the elevation of any dry returns as well as the steam mains in relation to the wet returns and the boiler, as when the zone valve is closed there will be no pressure on the down stream side, and water will rise in the drips to a level of 28 inches above the water line for every pound of boiler pressure. The possibility of flooding the steam mains is very real -- with resulting dramatic water hammer.

On the whole -- and having dealt with problematic zoning of steam systems -- my preferred course, assuming that the boiler is sized properly to do the job -- would be to leave the whole system open and control it with the main house thermostat. If this results in the office being consistently too warm, the first thing I'd try would be throttling the radiators in the areas which are too warm using their own valves, which is perfectly alright in a two pipe steam system. You could take your option 3 and control that zone valve with a thermostat, but keeping in mind that if the piping isn't correct it is going to hammer -- and when the zone valve is closed the boiler will cy

tcnjdeluca

Thank you Jamie,

Yes I posted about my situation a week or so ago. I did not mean to spam the board, but I did want to reassess the situation now that I have the heat working. I am trying to understand things the best I can so I can tell the pro when I have them out. I am trying to get the 2 zones to the same temperature now so I can see how it works just running off the main thermostat.