Repair or replace

Steamhead (in transit)

is a method of cycling the burner for varying periods of time based on outdoor temperature. On a steam system, this method varies the quantity of steam generated. On hot-water, it varies the water temperature.

With ODR, you can set the control unit to maintain a predetermined maximum building temperature (with all radiators fully open) and fine-tune each room with TRVs.

My educated guess is that the pneumatic system had ODR built into it. If the pneumatic piping is old and leaky, TRVs might be a better choice.

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B. McCready

Repair steam or replace with hydronic?

Our parish has a school building built in 1949 with steam heat. At 6,000 square feet per floor, two stories, and brick/block walls, it costs $3,000/month to heat (in northern Michigan.) The pneumatic control system is giving us trouble and the pastor is worried about the condition of the piping. One contractor has ball-parked $150 to $200k to abandon the steam system and install hydronic heat. Will this make for significant fuel savings? What can expect for a useful life of our current system? What about the hydronic system? How do you decide what to do?

ALH_4

Reduce the heat loss

It's hard to say without seeing the system, but the church's dollar will probably go farther by repairing the steam system and making an effort to reduce the heat loss (windows, doors, insulating where possible, etc).

Steamhead (in transit)

Fix the steam

This is usually the most cost-effective way to go. Piping that carries steam is almost always in good shape. Wet returns could be plugged or rusted, but these are generally a small percentage of the total amount of piping.

If the pneumatic system is shot, you might be able to get away with thermostatic radiator valves and outdoor reset.

Tell us more about the system. I assume it's 2-pipe? Does it have a vacuum pump?

"Steamhead"

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Mike T., Swampeast MO

1949 really isn't very old and with the possible expection of wet returns, the piping likely has many decades of life remaining.

Pneumatics are a very good system of control and it is still in use today. While extremely reliable, they are prone to problems if the air is not kept bone dry.

I'd do my best to find a good steam man--hopefully one with pneumatic experience. Otherwise find an engineer familiar with pneumatics and coordinate with a good steam man. Traps/vents/etc. may well be in need of service or replacement and could easily contribute to what sounds like excessive fuel use.

B. McCready

Fix the steam

Thanks Steamhead. It is a two pipe system, but does not have a vacuum pump. The 1949 boiler was fuel oil and was replaced with natural gas in the 80's. What is "outdoor reset"?

B. McCready

Vacuum pump

I went back to the plans for the project (bonus!) and see that a vacuum pump is shown (Hoffman #VVD-102). I have not been back to see if it is actually there. What difference does that make to the system?

Ross_7

Where are you located?

Where abouts are you located in northern Michigan?
Ross

Steamhead (in transit)

BIG difference!

If the system is designed to run with vacuum returns, it won't work well without that vacuum pump. The pipe sizes are too small. If the vac pump is gone or is not working, it can cause distribution problems. You may discover that the pneumatics are fine, and the pump is the problem. In a steam system, the symptom isn't always in the same place as the actual problem.

What can cause the pump to quit? Bad steam traps. If any steam gets into those return lines and reaches the pump, the pump will die. Rebuild the traps, and put an aquastat on the main return that will stop the pump if the return approaches 180 degrees or so.

Do NOT install one large trap on the return line at the pump. This misguided practice will make the situation worse- the condensate won't flow back to the pump as it should.

See chapter 12 of "The Lost Art of Steam Heating" for more. If you don't have a copy, order one from the Online Store of this site.

BTW, if Ross (above post) is in your area, I'm sure he could help you out.

"Steamhead"

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B. McCready

Location

Sault Ste. Marie - the eastern end of the upper peninsula.

Ross_7

I live in Marquette..

So, were practically neighbors! I now work for Northern Michigan University. We have centralized steam heating here on campus. However, I did service lots of steam systems around the local area, for other contractors before getting my "state job". I was just asked about this very same question last week, at the local trades building,I am a memeber of the U.P. Plumbers & Pipefitters Local 111,but I took an honorable withdrwawl card. I used to service that system, a Webster Type "R". I would keep the steam myself. It probobaly would take a lot less work to get the system operating efficiently again, than to convert it to hot water. Trap replacement & properly piping in a new vacuum pump would be first on the list. Possibly replacing the boiler(s) if necessary. These items would more than likely substantially reduce you heating bills I would try to get an estimate from a contractor who knows steam systems. There is a website you can try, UPCONTRACTORS.COM. See, if you can find one in the Sault, if not there are lots of contractors here in the Marquette area that can handle the job. If you need a reference for a particuliar contractor, I can probably help you out. Let me know how it turns out!

Ross

B. McCready

Steam contractors

Thanks Ross. We are now working with ACC Planned Services, based in Green Bay, but with an office in Sault Ste. Marie. I was thinking of speaking with Steve at Integrated Designs about options/evaluation. Do you know how knowledgeable he is on steam?