Entry # 91
Church Heating Problems Solved
Designer: Ben Rader
Customer: Church and Residence Facilities
Installation Location: Pleasant Prairie, Wisc.
Brief overview of the project
In the summer of 2015, a 12 year old cast iron boiler system used for heating a church compound was retrofitted with high efficiency condensing boilers and ECM primary loop circulators. The system’s secondary side was left intact including many types of emitters such as VAVs, various radiator types and in-floor radiant. After start-up and despite upgrades, the system was experiencing intermittent boiler performance problems. We were brought in and asked to remedy the problem.
Our goal was to identify the source of the issue and implement a solution before the heating season went full tilt.
We found magnetite present in large concentrations and likely existing throughout the system including far reaches of the secondary. How the magnetite was forming and the source of air ingress could not be exactly determined because of the large compound having sections impractical to analyze. The various air elimination devices appeared ok.
The design of the secondary piping and owner’s wishes made it impractical for us to blow out all of the secondary. So we took the approach of capturing debris before it could collect somewhere including the boiler. We had heard about Caleffi’ s magnetic dirt separator and decided to install one on the primary loop return header, with a plan to clean the primary loop and boiler and zone-by-zone capture the magnetite as zones began calling with the approaching cold weather. And to intermittently blow down the separator.
We conducted two blow-downs at weeks #2 and #4. As more zones came online the system experienced no issues. The first blow-down resulted in a surprising amount of magnetite eliminated. The second blow-down was somewhat cleaner and the third at week #6 cleaner yet.
The pictures here are of the third blow-down done in October. We since have conducted a couple more blow-downs and the amount crud being formed seems to have leveled out. The system continues to operate without any issues resurfacing. So far, so good!