From Rust to Robust: Rasmussen Mech Performs Industrial Boiler Refit

Rasmussen Mechanical has been in business since 1970, but after acquiring the C. G. Johnson Boiler Co. in 1986 the company made a name for itself in boiler repair and maintenance. Rasmussen currently features a wide service offering that includes temp controls, reliability solutions, mechanical construction and much more, with ten locations serving Iowa, Nebraska, South Dakota, Colorado, and the surrounding area.

Upon further inspection, the boiler was developing hot spots on the rear wall and side wall. As a result, the project included recasting, new insulation, and new refractory front and rear walls for this unit.

Originally designed as a temporary rental water tube unit, the boiler became a permanent fixture at the ethanol facility. Due to the boiler being operated outdoors, it was exposed to the elements, causing the boiler casing to

sweat, which, over time, caused the walls to completely rust out.

“Luckily the boiler pressure parts and internals were found to be in good shape and just the insulation walls were of concern as the boiler was 20 years old,” says Sam Larson, Quality Control Manager, Rasmussen Mechanical Services. “The repairs were more cost effective than purchasing and installing a new boiler. With good water treatment, the boiler pressure part should last the customer a long time.”

According to Larson, a five-member crew installed new blanket insulation on the side walls and roof with a 10-gauge steel outer casing. The front wall underwent a complete rebuild and gunite refractory was used for insulation. A new burner cone was then pounded and installed to meet original design parameters for the burner. Next, the rear wall was insulated with a castable refractory, which was poured in two sections—the lower and then the upper. A new ¼” plate was then installed on the rear wall of the boiler.

Following the rebuild, all boiler piping was reinstalled and refractory cure was performed by Rasmussen Mechanical burner technicians. Before they brought the

boiler back online, a combustion analysis and safety device testing were performed to optimize operations.

Boilers designed as rentals, like this one, use a blanket insulation on the front and rear walls to reduce weight so they can travel on roads. “The new poured, sprayed and pounded refractory on the front and rear walls will hold up for a much longer time than the blanket. The refractory should reduce the heat lost through the insulation/refractory to the outer skin casing,” says Larson.

At the time of the installation, despite facing adverse weather conditions such as extreme heat and rain, Rasmussen's skilled team completed the project in just 24 days.