Burners :

Propane firing - primary fuel - a propane line burner is furnished with this option.

Propane firing - standby fuel - a three-way hand valve is factory mounted. The pilot, however, stays on  natural gas. This option is not designed for use with mixed propane-air gas with properties similar to natural gas.  A standard burner will be furnished.  Contact your Hastings sales representative for special applications with two speed motors being used with dual-fuel.  Not available with selectra modulation systems or ETL units.

Gas Controls :

FM or IRI approved controls - additional gas manifold controls are furnished to meet insurance authority requirements.

High gas pressure regulator - a high gas pressure regulator is substituted for the standard regulator with inlet gas pressures over 1 PSIG

High or low gas pressure switch - manual reset type with adjustable set point.  Offered to meet special code requirements or where added protection is desired.  these gas pressure switches are part of the package furnished with FM and IRI options.

Selectra modulation system - a solid state electronic temperature control system is available to replace the standard self-contained modulation valve on units 500 MBH or less.  Both the Series 14 and Series 44 Selectra systems are described below.

SELECTRA MODULATION SYSTEMS

SERIES 14

Selectra Series 14 electronic gas flame modulation system features precise discharge air temperature control, decreasing variations or temperature "swings"

All components are pre-calibrated - not requiring matching sets.

Temperature selector is mounted in any convenient location or the dial can be incorporated in the remote control panel. Discharge air temperature can be quickly and easily reset to meet changing requirements.

Thermistor in the discharge air monitor continuously senses outlet air temperature and transmits an instantaneous signal, through a solid state amplifier, to the modulator/regulator gas valve.

Immediately responding to the signal from the sensor, the modulator/regulator valve changes gas pressure to control burner input and maintain discharge air temperature at a constant level.

Options include -

Over-riding room thermostat - two position control of space temperature.

Indoor-outdoor reset - raises discharge air temperature one degree for every eight degree drop in outdoor temperature.

SERIES 44

The Selecta Series 44 system converts a single purpose make-up air unit into one with dual operating characteristics , heating the ventilating air while controlling the space temperature.

Series 44 features electronic modulating space temperature sensing and control while, at the same time, preventing objectionable discharge air temperature extremes.

The basic system includes a solid state amplifier/control center, a discharge air monitor with high and low temperature thermistors, a modulator/regulator valve, and a space temperature sensor with integral temperature selector.

As an alternative, a selectrastat and thermistor sensing remote space temperature is also available.