Market Forge Industries ST-E STEAM IT, Service Manual

Page: 4 / 25

SEPTEMBER 14, 2017 4 ST-E ELECTRIC PRESSURE COOKER
ADJUSTMENTS & PARTS REPLACEMENT
NEW STYLE EXHAUST VALVE (AFTER JULY 1983)
Replacement instructions:
Disconnect fitting pressure gauge. Remove flue enclo-
sure. Remove old exhaust by unscrewing 1/4 IPS nipple
from cylinder. Remove safety relief valve assembly from
1/2 IPS nipple. Remove all fittings from the reducing tee
and remove tee and nipple by unscrewing nipple from cyl-
inder, remount nipple and tee in the front 1/4 IPS tap hole.
( Note that the use of the rear 1/4 IPS tap hole is eliminat-
ed, install plug as show on page 26 ). Mount new exhaust
valve assembly onto 1/2 IPS nipple previously used to
mount safety relief valve ( before mounting exhaust valve
assembly, install heat deflector plate on valve as shown
on page 26 ). Reconnect 1/4 OD tubing (steam pressure
line) as shown on page 0. Remount flue enclosure. Install
all new fittings, tubing and wire joints.
NOTE: All parts shown potted are existing to be reused
with new assembly. All items (except ref, items)
and one print of this drawing to be included with
this kit #10 to be used for shipping.
ELEMENT CONTROL SWITCH
The element control switch located under the removable
front lower panel, just left of center, governs the flow os
current to the heating elements to maintain cylinder pres-
sures at a near constant 14 PSI.
A copper tube extending from the top of the cylinder to
the rear position os the element control switch constantly
reflects internal cylinder steam pressure upon the built-
in bellows of the elements control switch to cause it to
open or close and electrical circuit to the contactor coil.
With little or no pressure applied to the bellows, the cir-
cuit to the contactor will be closed and providing the timer
is set to cycle, the contactor will click in and current will
flow to the heating elements. When the pressure rises to
14 PSI ( original factory setting ), the bellows will be suffi-
ciently compresses by the steam back-pressure to break
the circuit to the contactor coil, the contactor will click out
and current flow to the heating elements will cease. When
cooling allows the pressure to drop below 13 lbs., the bel-
lows will again complete the contactor coil circuit, activate
the contactor to click in and allow the heating elements
to energize. Thus, by working intermittently to open and
close the contactor coil circuit, the element control switch,
in effect, regulates current flow to the heating elements.