Steam boiler sizing help

LarryC

Are the Mains insulated? How about adding TRV's or reducing the size of the vents on the other radiators?

Larry C

Dave Stroman

Hey Steam Guy's....

Need a little boiler sizing help. It is a new Burnham boiler. Less than a year old. The last radiators on the main do not get hot. Changed all the air vents. The boiler seems to make steam ok, no banging, water level stable. The main vent does see steam and closes. But the last radiator stays cold. There just does not seem to be any pressure build up. Took the air vent out of the last radiator and no pressure. Closed off the first 3 radiators on the main and the last one quickly got hot.
The connected load is 227 Sq. Ft. Per Dan's formula- 227 x 1.5 x 240= 80,640 Btus. The D.O.E. rating on the boiler is 87,000. I assume that at 5280 ft high, I need to derate the boiler about 20%. Would that put the DOE at 69,600? Too small for the connect load. Just trying to check my reasoning before I give the homeowner the bad news.

Dave in Denver

Dave Stroman

The mains are not insulated. There is about 100 feet of 2 and 1 1/2 pipe.

Dave in Denver

Steamhead (in transit)

First thing I'd do

is insulate the mains. A bare pipe loses about five times the heat than an insulated one does. I'll be surprised if this does not solve your problem.

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Dave Stroman

Thanks steamy. I will try that.

Dave in Denver

Brad White_9

Bare 2 inch pipe

is worth 0.622 EDR per linear foot and 1.5 inch pipe worth 0.497 EDR per linear foot. Your 100 feet, say half of each of it, is worth over 13,000 BTUH if in a 70 degree space (not adjusted for altitude mind you!).

As Steamhead said, insulate that and you will keep and deliver about 80% of that, probably more than you need.