Is it time for these snowmen to go?

mac_pro

I would like to replace three coal converted to oil converted to gas boilers for the three single-pipe steam systems in my Cambridge, MA three-decker.



Plan A: Replace the No. 2 boiler's upshot gas burner (low output problem) and hope the minor leaks don't get worse.



Plan B: Replace all three boilers with new steam boilers. Replace insulation on basement pipes. (Previous owner took it off "to warm the basement.") Fix a few leak and pitch problems.



Plan C: Abandon steam (just when we were getting along) and go to hot water, high velocity air, split unit heat pumps, or something else.



After fixing multiple problems (pressure, pitch, air valves, leaks), I think that these single-pipe systems are close to working really well. (Only one of the seventeen radiators has inadequate heat.)



Three new boilers seems like a good option, but it may not be cost effective.

Also, I've been told that there are no good choices available for new small boilers.



Any opinions?

nicholas bonham-carter

Abominable Snowmen

can you replace the three with one? --nbc

mac_pro

Can that be done?

That would be an attractive option, but I don't know if it's possible.

(Way above my steam paygrade.)

jim s_2

No good choices?

Who told you that?

Anything would be an improvement over what you`ve got there and yes there are good smaller boilers out there.

The Steam Whisperer (Formerly Boilerpro)

Smaller boilers.....

Well Slantfin, my favorite for most installs,  makes one down to 105,000 input and Burnham, who probably makes the best basic atmospheric unit, makes one down to 62,000 input.    You could go a single boiler, but would need zone valves and maybe a condensate pump.  Also, it would probably not run as efficient unless you could stage fire it so it would run at low output when only a single or 2 zones were running.  Gerry Gill has made this simple modification to the Burnhams successfully, so that would probably be the best choice.  I like the Slantfin Galaxy units because they are very easy to maintain, at a good price point, make very good steam and are very easy to install. 

Steamhead

Is your 3-decker

split into apartments that are separately metered? That trio of snowmen tells me it was probably built that way. If you want to keep tenants paying for their heat, you'll need to go with three boilers.



We're actually replacing another snowman this week, using a Smith G-8- same swap-out we did last week though this one is oil-to-gas. The G-8 has a better thermal efficiency than the typical atmospheric gas boiler, so we expect both homes will save lots of fuel. The 3-section G-8 we're using has a rating of 283 square feet EDR, though, so unless each of your "decks" has close to that amount of radiation, even that smallest G-8 would be too big.



If you post your EDR figures for each deck, we can make some more-specific recommendations.

mac_pro

Here's a bit more

Wow. Thanks for the great response.



I don't have EDRs, but I might get enough information tomorrow to help with educated guesses.



In the meantime, here's what's on the upshot gas burners (circa 1980):

45,000 minimum input BTU per hour

300,000 maximum input BTU per hour

The EDR is what we really need, but maybe this can get us in the ballpark.



Each of the three apartments is about 950 sq. feet.

The apartments have insulation and new windows but there are still plenty of air leaks.

Rod

EDR Sheet

Hi - Attached is  a worksheet that will help you calculate the EDRs.

- Rod

The Steam Whisperer (Formerly Boilerpro)

Separate metering of single steam boiler

I believe that BTU meters are also available for steam, as they are for hot water, so a single boiler can be used but with separte metering.  However, I am not sure of the cost of the steam BTU meters.

mac_pro

EDR is 170

Thanks for the worksheet.



If my numbers are correct, the EDR is 170 sq. ft. per floor.

And, from the worksheet, 40,800 BTU load.

jpf321

btu meters ...

you might want to reach out to this company: http://www.istec-corp.com/

mac_pro

Runtime Meters

I'd have no trouble building a device that could record the accumulated time each thermostat is on while the boiler is producing steam. Each floor's heating cost would be determined by the number of steam-hours per month.



And, of course, as long as I'm building things, the next step would be constructing a Web page for the boiler. Then everyone could see the status of each thermostat, riser temperature, run times, etc.



At this point I've obviously got too much spare time on my hands, so I might as well add email and texting. Now the boiler could send me a text message if the low water cutoff trips or if it was taking too long for the steam to come up or...