Published: March 26, 2020 - by Dan Holohan

Categories: Hot Water


In this excerpt from his Classic Hydronics seminar, Dan Holohan tells a story about a mansion that had two Ideal Redflash boilers, each with a rating of 500,000 Btuhs. Dan talks about the importance of doing a heat-loss calculation for boiler replacement jobs, why this house (with only a heat-loss calculation of 375,000 Btuhs) had two giant boilers, and how they solved the problem with primary-secondary pumping.

Want to learn more? Read Dan Holohan’s book Classic Hydronics: How to Get the Most From Those Older Hot-Water Heating Systems.