Hubbell MSH - Manual (Page 9)

9
Model MSH & MH
Shipboard Electric
Water Heater
9
Optional Steam Package
Steam Component General Configuration
The steam control valve maintains accurate water
temperature in a steam fired water heater by regulating
the flow of steam through the heating coil.
There are four types of steam control valves available for
use on a steam fired storage water heater.
Pilot Operated
A pilot operated control valve is the most widely used
type of valve for standard water heating applications.
In this type of valve, a temperature pilot device utilizes
steam to operate the main valve. No external power
source is required other than steam. This is a highly
dependable temperature control system which is suitable
for most applications. As an option, this valve may
include a pressure reducing pilot which limits the steam
pressure to a predetermined maximum.
Electronic Operated
This control valve is similar to a pneumatically operated
system, except in this case the temperature controller is
a sophisticated digital display electronic device which
outputs a 4-20ma signal to a compact motor mounted
on the steam control valve in order to proportionally
control the flow of steam to the heating coil. The
temperature controller displays set point as well as
actual water temperature and is available with an RS485
communications port for remote control.
Self Operating
The valve design includes a bulb and capillary assembly
charged with a thermally responsive vapor. The
expansion/contraction of the vapor acts upon the valve
bellows in order to control the flow of steam through
the valve. No external power source is required for
operation.
Pneumatically Operated
In this configuration the ships air supply feeds a factory
installed temperature controller which operates the
steam control valve. The temperature controller sends
a precise air signal to the steam control valve which
adjusts the flow of steam into the heating coil. The
temperature controller is fully adjustable from 50-250°F
and requires 20psi air at a maximum consumption of 0.5
SCFM.
Steam Inlet
Y Strainer
Condensate Outlet
Steam
Control
Valve
Adjustable
Temperature Pilot
To sensing bulb
in tank
Thermostatic
Drip Trap
Steam Pressure Gauge
Pneumatic or electronic
controller (if required)
Vacuum Breaker
Steam Coil
Y Strainer
F & T Main
Condensate Trap
Model MSH & MH
Shipboard Electric
Water Heater