Market Forge STM-E Service Manual
STERILMATIC
ANALOG ELECTRIC STERILIZER
PARTS AND SERVICE MANUAL
EFFECTIVE APRIL 15, 2016
The Company reserves the right to make substitution in the event that items specied are not available.
ERRORS: Descriptive and/or typographic errors are subject to correction.
44 Lakeside Avenue, Burlington, Vermont 05401 USA Telephone: (802) 658-6600 Fax: (802) 860-3732
Superseding All Previous Parts Lists.
MARKET FORGE INDUSTRIES
www.mi.com
P/N 14-0412 Rev D
TABLE OF CONTENTS
DOOR ASSEMBLY & ADJUSTMENT ....................................................3
FULCRUM AND DRAIN ASSEMBLY .....................................................5
PRESSURE ACTUATED TEMPERATURE CONTROL .....................................6
MISCELLANEOUS COMPONENTS .....................................................8
TROUBLESHOOTING ................................................................ 10
ILLUSTRATED PARTS LIST ...........................................................11
APRIL 15, 2016 2 STM-E, STM-EL, STM-EX & STM-ELX STERILIZERS
DOOR ASSEMBLY & ADJUSTMENT
STERILMATIC DOOR ASSEMBLY
The Door of the Sterilmatic has been engineered to establish a positive method of sealing the steam pressure
within the sterilizing cylinder. As steam pressure builds
up within the cylinder, the door seal will tend to become
more positive.
However, the door should be adjusted to make a good
initial seal between the door gasket and the door opening
without the added assistance of internal cylinder steam
pressure with the simple action of securing the door handle down in a locked position, the door gasket should be
sufciently compressed against the door opening, all the
way around to prevent any steam leakage from occurring.
DOOR ADJUSTMENT
The Door Adjustment is Located in the Fulcrum Casting
at the base of the door opening. This adjustment employs
the use of a screw and locknut in order to adjust the Sterilmatic Door to a tighter closed position (to prevent steam
from leaking by the door gasket as pressure builds up), it
is necessary to loosen the locknut and back off the screw
at least one-quarter of a turn and re-tighten the locknut.
Figure 1
Figure 2
THE DOOR GASKET
Keep the gasket clean. With normal closing and locking
of the door assembly, a steam-tight seal should be made
between the door gasket and the door opening. This seal
cannot be maintained if particles of foreign matter are allowed to accumulate upon either of the contacting surfaces.
If there is leakage by the door gasket before a steam
build-up within the steam chamber and leakage does not
stop when the sterilizer reaches sterilizing temperature
and pressure than regard the door assembly as improperly adjusted. A re-adjustment must then be made of the
seal adjustment door screw.
To change the door gasket, remove the entire door assembly as a unit. Discard the old gasket, replace it with
a new one (no cement is required), and reinstall the door
assembly. Make an operational check for leakage and adjust the door, if necessary.
APRIL 15, 2016 3 STM-E, STM-EL, STM-EX & STM-ELX STERILIZERS
DOOR ASSEMBLY & ADJUSTMENT
DOOR LIFT SPRING
Market Forge supplies door lift springs in sets only. This
policy has been found to be in the best interest of the
customer. Through continuous use, some of the original
qualities of the springs are lost and it becomes advantageous to make replacements to both the left and right
door lift springs in the event that one becomes damaged
or broken.
Replacement door lift springs are marked with tabs at
the factory prior to shipment to identify a right from a left
spring. These springs must be installed with the right
door lift spring on the right of the door and the left door lift
spring on the left of the door as viewed from the front of
the sterilizer.
TO REMOVE THE DOOR ASSEMBLY
The Door Assembly can be removed from the inner sterilizing chamber as a unit without the use of any special
tools or equipment. However, a systematic approach to
this is warranted as the clearances through the portal are
close, and much confusion can result if not removed in
the sequence described below:
1. First, lift off and remove the two pan supports to expose the door linkage on either side of the inner sterilizing chamber .
2. Raise the door to a fully opened position, and disengage the door spring from each of the door spring
studs. Accomplish this by counteracting the force of
the door lift spring with one hand while working the
end of the door spring off the spring stud with the free
hand. Do this on both sides of the door assembly.
3. When the end of the door springs have been completely freed from their respective door spring studs,
the door springs on either side of the door assembly
can easily be slipped off their studs.
4. Rotate the entire door assembly out through the
door opening, passing the door handle through the
opening rst, and then one end of the door spring as
shown in the illustration. The remainder of the door
assembly will then pass through the door opening
quite easily.
5. To replace the door assembly, reverse the step-bystep procedure described above.
Figure 3
ITEM PART NO. DESCRIPTION
1 10-6765 Pivot Spring Bearing
2 91-2718 Right and Left Door Spring (sold as a pair)
3 10-1776 10-32 Machine Screw 1/2” Long
4 10-2666 Door Gasket
5 95-3204 Door & Door Spring Assembly
- 95-0124 Items 1 through 5
APRIL 15, 2016 4 STM-E, STM-EL, STM-EX & STM-ELX STERILIZERS
FULCRUM AND DRAIN ASSEMBLY
THE FULCRUM & DRAIN
ASSEMBLY
The fulcrum and drain assembly is located at the lower front
of the sterilizing chamber and
furnishes a sturdy anchorage
for the door locking system of
the door handle. Also provided
in this assembly is a means for
adjustment of the door seal. The
drain port and drain valve provide a means of discharging accumulations of water from within
the sterilizing chamber.
ROLLER ASSEMBLY
(ITEMS 8 & 9)
The Roller Assembly must be
kept free-rolling at all times.
Should this assembly be allowed
to become frozen due to lack of
lubrication, undue strain will be
put on the door handle and the
fulcrum casting while the door
is being locked. Use only a dry
lubricant such as graphite; as oil
or grease will tend to attract dirt
to this area.
Figure 4
ITEM PART NO. DESCRIPTION
1 10-3116 1/4” - 20 X 5/8 helicoil
2 10-1999 10-32 Machine screw, 1 5/8” long
3 10-2358 1/4” - 20 fulcrum nut
4 10-2087 1/4” - 20 allen set screw
5 10-3111 1/4” - 20x 3/8 helicoil
6 10-2513 1/4” Shakeproof washer
7 10-1763 1/4” - 20 Machine screw 3/4” long
8 95-0120 Bearing spacer
9 95-0198 Bronze Bearing
10 10-3111 1/4” - 20 x 3/8 helicoil
11 10-2513 1/4” Shakeproof washer
12 10-1790 1/4” - 20 Cap screw 7/8” long
ITEM PART NO. DESCRIPTION
13 10-4485 Drain valve knob
14 10-2514 #10 Shakeproof lockwasher
15 10-2318 10-32 acorn nut
16 95-2643 Adapter - steinball valve
17 10-1950 6-32 Round head screw 1 5/8” long
18 95-2616 Front outer case lower
19 95-0116 Fulcrum and drain casting
20 10-1049
21 10-1041 Ball valve stein
- 95-0115
Nipple 1/2” IPS 2 1/4” long stainless
steel
Fulcrum and drain assembly, Items 1
through 12, 14, 15, and 19
APRIL 15, 2016 5 STM-E, STM-EL, STM-EX & STM-ELX STERILIZERS
PRESSURE ACTUATED TEMPERATURE CONTROL
STM-E AND STM-EL
The pressure actuated temperature control, located behind the control panel assembly, governs the manufacture of steam by controlling the input of electric current to
the heating elements.
HOW IT WORKS
When the Timer is set, rear and front contactors will become energized allowing input of current to the temperature control, thus closing the contacts completing the
current to the heating elements. Steam will then be generated within the sterilizing chamber.
The steam pressure within the sterilizing chamber is
transmitted by means of a tube to the bellows of the temperature control; as the steam pressure increases, its
compression action on the bellows is set to cause the
Switch #1 on the control to cut out on rising pressure at
13.5 PSI and to cut in on falling pressure at 13 PSI (controlling the two outer banks of heating elements). Switch
#2 is set to cut out on rising pressure at 15.5 PSI and cut
in on falling pressure at approximately 15 PSI (controlling
center heater element only).
Thus, a balancing effect of steam pressure build-up and
heater element current is constantly maintained during
the sterilizing cycle. When the Timer signies the end of
the cycle, the electric current to the contactors will automatically be broken; the temperature control contacts will
be broken; and steam generation will stop.
ADJUSTING THE RANGE OF OPERATION, STM-E
NOTE: These instructions should be performed by
qualied service personnel only.
The operational range of the temperature control is factory set as follows: Outer bank of elements OFF at 13.0-
13.5 PSI; Center bank of elements OFF at 15.5- 15.0 PSI;
minor compensating adjustments can be made by turning
the adjusting screws counter-clockwise to increase pressure and clockwise to decrease pressure. Both screws
should be turned the same amount when making an adjustment.
NOTE: When resetting this control for elevations above
sea level a correction of 6/10 Ib. per thousand
feet is necessary.
1. Before making adjustments, shut all electrical current
to the sterilizer OFF to eliminate shock hazard.
Figure 5
CHECKING THE 230° SETTING, STM-EL
The Unit should be completely evacuated then temperature selector dial should be turned on 230° Fahrenheit.
Observe the current until it takes a sharp drop to approximately one-third of the full load; at this instant, there
should be a corresponding chamber pressure of 2 PSI
Observing the current further will show another sharp
drop to approximately 2 Amps; at this instant, there should
be a corresponding chamber pressure of 6.1 PSI and a
temperature reading of 228° to 232° Fahrenheit, on the
temperature gauge.
ADJUSTING THE RANGE OF OPERATION
STM-EL
The range of operation of Model STM-EL is adjusted by
simply turning the adjusting knob on the outside of the
Control Panel. A counter-clockwise turn decreases the
pressure while a clockwise turn increases the pressure.
Observe pressure and temperature gauges and adjust
knob as required.
NOTE: When resetting this control for elevations above
sea level, a correction of 6/10 Ibs. per thousand
feet is necessary.
2. Remove the Flue Cover.
3. Make sure that all exposed wires are not in a hazardous position, and then turn on electrical power.
4. Run unit through cycle, observing pressure and temperature gauges, turn adjusting screws as required.
APRIL 15, 2016 6 STM-E, STM-EL, STM-EX & STM-ELX STERILIZERS
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