I have a Delco boiler which is quite old. 120,000BTU. Model GB135LP or GB35LP. Serial # 1446. Service 5082793. How old is this unit and what would be the estimated efficiency? I'm thinking about replacing with a high efficiency by the end of this year to take advantage of the 30% Federal rebate. The boiler still seems to work fine. Thanks for any info. Jack Cobb

Jack Cobb

The efficiency is about 60%. New ones are from 80% to 95% and have pumps on the water system which circulates your water faster. Don't be alarmed if the new unit is twice as small as the old one.






























5 to 95%