8 Unit Garden Apartment Complex
1 Bedroom, 1 Bath

We were brought in to an apartment complex to diagnose a boiler room that was leaking water and on life support. Upon further inspection the old units needed to be replaced.

We removed the old Burnham 80% 808H at 435,000 Btu at 80% thermal efficiency. They were originally set to maintain 180° boiler water every day of the year. The indirect water heater had 119 gallons of stored domestic hot water.

This was then replaced with a US Boiler Alpine 210,000 Btu at 95% AFUE with outdoor reset. We programmed the outdoor reset curve to produce 180° water temperature at 32° outdoor temperature or below. This would turn the central heat off at a 70° outdoor temperature.

A 26-gal instantaneous indirect water heater was installed and two fixed speed circulator pumps with ECM variable speed were replaced. The pumps reduced power consumption from 170 watts to 90 watts at full speed.

The final results:

Reduced input Btu’s by 51.7%

Increased efficiency by 15%

Reduced stored hot water by 78%

Reduced parasitic electric consumption by 47%