STERLING HSB24011 Hot-Water Unit Heater | Montreal, Laval, Longueuil, South Shore & North Shore

A large unit heater whose loop is designed along with the unit

The HSB24011 in published figures

The Sterling HSB24011 is a horizontal hot-water unit heater from the HS series. Hung from the ceiling, it blows 3,500 CFM of warmed air, at 900 FPM at the outlet, through horizontal louvers that come standard. Sterling rates it at 174,000 BTU/h with 200°F entering water, 60°F entering air and a 20°F drop. Its single-speed 1/3 HP motor connects on 115 V, single phase, 60 Hz.

This size targets distribution centres, heavy machinery maintenance shops and storage hangars, in buildings equipped with a good-sized electric boiler.

Designing the loop: flow, pressure drop and balancing

At this size, the unit is no longer chosen on its own. It needs 17.4 GPM with a 20°F drop, and its coil’s pressure drop reaches 1.06 ft H2O. The circulator must supply that flow on top of the other circuits; depending on the case, we keep the existing circulator or propose a dedicated one.

If the building receives several unit heaters, the loop must be designed for all the flows, with balancing valves so that each unit gets its share. We draw that layout before the quote, and the electric boiler must have capacity to spare for the whole system, at the chosen temperature.

Water temperature and loop fluid

The 174,000 BTU/h rating applies to 200°F water. Below that, Sterling publishes the factors to apply: 0.857 at 180°F, 0.715 at 160°F, 0.571 at 140°F, 0.429 at 120°F and 0.286 at 100°F. With an air-to-water heat pump, a larger size or an extra unit may be needed; we present the options, with the calculation to back them.

In a hangar that can freeze, the loop can contain propylene glycol, for which Sterling publishes correction factors. The coil is rated up to 150 PSI (1,034 kPa) or 320°F (160°C) on hot water and factory tested at 200 psig (1,379 kPa) under water.

What our installation covers

We confirm the weight, dimensions and connections with Sterling, then check the structure that will carry the unit. Our technicians hang it by rods, level, connect it to the loop with isolation valves, balancing valves as needed and air purging, make the 115 V electrical connection and the control, then start it up and measure the flows.

AirGreen is a family business established in Montreal for more than fifteen years, holding RBQ licence 5645-9605-01 (ventilation, refrigeration and electrical). We serve Montreal, Laval, Longueuil, the South Shore and the North Shore.

Ask for a free on-site estimate: your written quote covers the unit, the loop and the circulator, and financing is available.