Cold radiators

gjb

I have a three-unit building with an oil boiler and hot water radiator heat. The house was built in 1925. The pipes flow out and leading into the boiler are 3" (maybe more) in diameter. The boiler itself is huge (and old), but after servicing it rates at 91%. I have two problems/questions:



First, I live in the building and control the thermostat. There's one thermostat on the first floor. Everything is on one zone. Anyway, the apartments are about 1,100 square feet each with a radiator or two in each room. Last year, I used more than 2,200 gallons of oil to heat the building (more than $5,000). This was to keep the house at 68 degrees, letting it dip to 62 at night and during the day when folks are at work. The contractors I've had in can't explain why the pipes are so big and are amazed at how much oil I burn (at peak of winter, I went through a 250 gallon tank every two weeks). Any suggestions of what to do to reduce expenses? Type of replacement? Or any lower cost solutions, as money is in low supply.



Second, a couple radiators on the first floor and the third floor either remain cold or get barely warm. I've bled all the radiators, but still no heat. What to do? Thanks for the help.

CMadatMe

I highly Doubt You

are running 91% efficient. Don't worry about the size of the pipe. A good contractor wouldn't. He would start by walking around your building and doing a heat loss, telling you where to tighten up on air infiltration, and give you a course of action. Sometime depending on the structure, investing in good windows, insultation and fixing leak infilitration is a better investment for the short tem until you can afford a new piece of heating equipment.



Keep in mind a boilers efficiency rating is the rate at which it produces energy not the rate of the systems efficiency nor does it take into consideration the bldgs envelope.

Charlie from wmass

Gravity hot water

I am guessing this is why you have such large pipes. Air or weak pumps, or even a closed valve could be the cause of the cold raditators. If it is converted from a gravity system there may be other issues. Did those radiators ever heat well?