My boss planned the job and then I was asked to execute it. Place a UPS in front of the controls for a small gas fired boiler. Seemed simple enough. Once everything was in place I did a test and watched the UPS shutdown on overload. Then I started doing what I should have done in the first place - check the details of the installation. The UPS output was insufficient. The inrush for the fan motor was 31A and the UPS output is 12.5A. The default overload setting is >102% with a max setting of >150% (for 100ms). Right on the boiler controls itself it states that a minimum circuit ampacity of 13.25A is required. Red flags all over the place if I had only taken a few minutes to double check the details. My boss is an experienced electrician who seldom makes these types of mistakes. Looks like I'll have some bad news for him on Monday morning. Gotta love Mondays.
