Steam Coil

Steam coils are a common heat source in an air handler to provide heating for many commercial and industrial buildings. The supplied air from the fans is warmed by moving across aluminum, stainless or copper fins. The fins are warm from the exchanged heat of the steam going through the tubes. You may also see steam coils in rooftop units or ductwork.

Most steam coils we see use low pressure steam around 5 to 15 PSI. We do sell steam coils for applications that use much higher steam pressure that are typically for process heating in a factory. In this case it’s common to see stainless steel tubes used which can withstand the high pressures and temperatures.

Elementary Surface
Round seamless copper tubes are expanded using hydropneumatics water expansion system into the fin collars of the secondary surface. The hydropneumatics water expansion system provides a permanent metal-to-metal bond for efficient heat transfer. Tubes are staggered in the direction of airflow.

Secondary Surface
Corrugated aluminum or copper plate type fin that is die-formed. Fin collars are full-drawn to provide accurate control of fin spacing and maximum contact with tubes.

Headers
Seamless copper with die-formed holes that provide a parallel surface to the coil tube for strong brazing joints.

Connections
Red brass Schedule 40 male pipe thread (MPT) is standard with optional copper female pipe thread (FPT) and sweat available. Maximum fin length of 108” with same end connections. Steam pressure above 50 PSIG will have opposite end connections.

Casing
Casing is die-formed with 1½” flanges to permit easy stacking and mounting. Coil as shown above must be mounted level (NO pitched case). Opposite end connection coils can be supplied with pitched casing. Intermediate tube supports are supplied on coils over 44” fin length with an additional support every 42”.

Testing and Performance
All coil assemblies are leak tested under water with nitrogen at 315 PSIG. Standard construction is suitable for 25 PSIG steam pressure. Heavier wall construction is available for steam pressures up to 100 PSIG.