Third Party UL Testing Offers Real Measure of
Boiler Efficiency
UL has developed a new method of efficiency testing for condensing, fully modulating boilers that offers a more accurate reflection of how equipment will operate in the field. This offers genuine value to engineers and building owners. It’s also a way of showing true 3 rd party efficiency testing results and not just marketing claims or ANSI Z21.13 or BTS-2000 test results that don’t use realistic operating conditions. Also, many boiler companies do not publish their part load efficiencies. These part load efficiencies are important due to the fact that boilers mostly operate at reduced fire. In fact, modulating boilers operate at a part load or partial firing rate the majority of the heating season. These UL efficiency test results show thermal efficiencies at full fire, low fire, and various firing input rates in between. The chart below shows tests witnessed and reviewed by UL for an AERCO BMK2.0LN boiler with a 20:1 turndown ratio. These tests also were done with a 20°F rise and not the industry standard 100°F rise (80 – 180 F°).
Note: Most boiler manufacturers will state in the O & M manuals not to send return water below 140°F but will test their boilers to these outdated standards using 80°F return water temperature just to get a higher % on their efficiency to publish in their literature.
As more boiler manufacturers open their labs to independent, 3 rd party testing, all boiler manufacturers will be required to test based on operating conditions specified in their warranty and O&M guidelines.
AERCO boilers are certified in accordance with UL-795 standards. Most manufacturers use the ANSI Z21.13 standard. ANSI Z21.13 is not part of UL-795.
Just because hydronic and steam components & accessories are packaged and pre-fabricated on a skid, doesn’t mean that the end result is a package with features that benefit the owner.
