Technical content reviewed November 13, 2026 · Tillman & Associates
Where FR fits
FR is the frost-resistant heat-exchanger unit-heater family. The catalog highlights steam applications exposed to freezing conditions, including outdoor installations. An electric fan moves air across the steam-heated core.
Begin with the steam supply and the required heating duty. FR should not be selected as a hot-water, glycol or oil cooler: the current FR/HP owner’s manual identifies FR as steam-service only.
Frost resistant does not mean freeze-proof
The catalog discusses accidental system freeze-up and recommends returning an affected heater to Thermon for inspection. Frost-resistant construction is not permission to ignore drainage, trapping or the consequences of a steam-supply interruption.
Tell Tillman about shutdowns, minimum ambient temperature and the condensate-return arrangement. A useful application review covers the operating sequence as well as the heater’s nominal output.
Steam conditions and condensate
Provide the available steam pressure at the heater, entering-air temperature and required heat output. Also identify return-system pressure, lift and control method so the piping arrangement can be reviewed.
The current manual limits steam to single-pass models and calls for the exchanger data plate to establish pressure and temperature limits. Use the exact selected-unit rating rather than a broad pressure claim from older literature.
Motors, controls and maintenance access
The catalog offers different motor and construction choices; hazardous-location suitability applies only to the appropriate rated assembly. Submit the complete classification and motor supply, plus any protective-finish requirements.
Plan support and access for inspection, cleaning and core service. The steam and condensate components form part of the installation, so send a piping sketch when replacing a heater that has had drainage or freeze-up problems. Tillman can coordinate the selection questions with the manufacturer.
What to send Tillman
- Required heat output and entering-air temperature range
- Steam pressure at the unit and design conditions
- Condensate return pressure, lift and proposed control sequence
- Freezing exposure, shutdown pattern and any prior freeze-up
- Motor voltage, phase, frequency and site classification
- Mounting, piping sketch, exchanger/motor labels and quantity
Common questions
Can FR be used with glycol?
The current owner’s manual identifies FR as steam-service only. Ask Tillman about a suitable liquid-service family.
Is FR freeze-proof?
No. The catalog recommends factory inspection after accidental freeze-up.
Is every FR unit explosion-proof?
No. The selected motor, assembly certification and operating conditions must match the location.