Hubbell Electric Heater Company V20 - Manual (Page 8)

8
Dial Temperature and Pressure Gauge
A combination temperature (70° - 250° F) and pressure (0 –
200 psi) gauge with 2½-inch dial may be supplied for in-
line installation (shipped loose).
Vacuum Relief Valve
A vacuum relief valve may be provided with the unit to reduce the risk of back siphonage and back
pressure of the system. The valve will be shipped loose for in-line installation. Instructions for
installation are provided with the valve.
Individually Fused Elements
To prevent the possibility of damage to control circuits and other elements in case of electrical
overloads, fuses may be supplied for each element. Two types of fuses may be used; a type NON for
voltages less than 250-volt or type JJS for voltage less than 600-volt.
Type JJS Type NON
Built-in Circuit Breaker
A built-in circuit breaker may be provided with or without shunt trip protection for protection from
circuit overload.
NEMA 4X Electric Control Panel
A NEMA 4X control panel may be supplied to provide watertight construction for installation in “wet”
areas.