Description

1.1 Scope of Manual

This manual contains detailed troubleshooting, scheduled maintenance, maintenance, and service instructions for the M7 SpeedClave ® Sterilizer. This manual

is intended to be used by Midmark’s authorized service

technicians.

1.2 How to Use Manual

A. Manual Use When Performing Scheduled Maintenance.

(1) Perform inspections and services listed in

Scheduled Maintenance Chart (Refer to

para 3.1).

(2) If a component is discovered to be faulty or out

of adjustment, replace or adjust component in

accordance with Maintenance / Service Instructions (Refer to para 4.1).

B. Manual Use When Sterilizer Is Malfunctioning And

Cause Is Unknown.

(1) Perform an operational test on sterilizer (Refer

to para 2.1).

(2) Perform troubleshooting procedures listed in

Troubleshooting Guide (Refer to para 2.2).

(3) If a component is discovered to be faulty or out

of adjustment, replace or adjust component in

accordance with Maintenance/Service Instructions (Refer to para 4.1).

C. Manual Use When Damaged Component Is Known.

(1) Replace or adjust component in accordance

with Maintenance/Service Instructions (Refer to

para 4.1).

1.3 Description Of M7 Sterilizer

A. General Description (See Figure 1-1).

The M7 SpeedClave ® Sterilizer is a self generating

steam sterilizer designed to sterilize instruments and

other sterilizable goods. The major components of the

sterilizer consist of a chamber, condensing tank assembly, heating element, temperature regulator relay,

diaphragm cup, timer assembly, timer buzzer, manual

reset overheat thermostat (low water), auto-reset

overheat thermostat (low water) (auto-reset overheat

thermostat is only on newer units with CS or RB serial

number prefixes), pilot light, fill / vent valve, bellows

assembly, pressure relief valve, temperature gauge,

and reset button linkage assembly.

B. Theory of Operation (See Figures 5-1 thru 5-3).

Electrical Operation

Current flows thru the normally closed contacts of the

overheat thermostat(s) (also known as the low water

thermostat) to one side of the contacts on the timer

switch. When the timer assembly is not set to a time,

the timer switch contacts are not closed and no path to

the heating element is completed. When the operator

sets the timer assembly to any time setting, the timer

switch contacts are closed allowing current to flow

across the normally closed contacts of the temperature

regulator relay and be applied to the heating element,

causing it to heat up. Current is also applied across the

pilot light causing it to illuminate, thus indicating that the

heating element is energized. The diaphragm cup is

pressure sensitive and expands outward as the pressure in the chamber increases. The normally closed

temperature regulator relay is adjusted so the diaphragm cup will push open the contacts of the relay

when the selected temperature / pressure is reached

during a sterilizing cycle, de-energizing the heating

element. When the temperature / pressure lowers

slightly, the diaphragm cup contracts allowing the

temperature regulator relay to close its contacts which

causes current to be applied to the heating element and

pilot light again. The temperature in the chamber is

regulated to within +1° to +2° of the selected temperature during the cycle by the continuous opening and

closing of the temperature regulator relay contacts by

the diaphragm cup. The timer assembly contains a

timer motor which runs the timer assembly. When the

timer is run down to a setting of 0 minutes, the timer

switch contacts move, breaking the circuit to the

heating element and pilot light. A circuit to the timer

buzzer is now completed, causing it to sound. The

timer assembly timer motor continues to run for one

minute. Then the timer switch contacts are opened,

causing the timer buzzer to stop sounding.

During the cycle, if the temperature inside the chamber

rises up higher than 285°F (141°C), the normally closed

manual reset overheat thermostat (also known as low

water thermostat) contacts open, breaking the circuit to

the timer switch, heating element, and pilot light. The

most frequent cause of activation of the overheat

thermostat is a low water condition in the chamber. The

N.C. auto-reset overheat thermostat is a safety backup

for the manual reset overheat thermost and opens at

295°F (146°C). The manual reset overheat thermostat

is reset by pressing the RESET button located on front

panel of the sterilizer and the auto-reset overheat thermostat automatically resets after approximately six minutes.

Water / Air / Steam Flow

The M7 sterilization cycle has four phases; filling, heat

up, sterilizing, and venting.

During the fill portion of the cycle, the operator depresses the FILL / VENT lever which opens the fill /

vent valve. Water flows from the condensing tank thru

the fill / vent valve and into the chamber. When the

operator visually observes that the water level in the

chamber is within 1/2 in. to 5/8 in. (13 to 16 mm) from

the front rim of the chamber, the operator releases the

FILL / VENT lever, closing the fill / vent valve. Now the

operator begins the heat up portion of the cycle by

turning on the timer assembly.

During the heat up portion of the cycle, the water is

heated by the heating element. As the water begins to

boil, air is bled off thru the bellows assembly into the

condensing tank. When the bellows assembly senses

pure steam flowing thru it, the valve in the bellows

assembly closes, allowing pressure in the chamber to

build. The sterilizing portion of the cycle begins when

the bellows assembly is completely closed, not allowing

steam to flow thru it, and the desired temperature in the

chamber for the selected cycle is reached. The operator sets the timer assembly for the desired length of the

cycle and the cycle is run.

When the timer assembly counts down to 0 minutes

and shuts off the heating element, the vent portion of

the cycle begins. After the door handle has been

moved to the vent position, the operator depresses the

FILL / VENT lever which opens the fill / vent valve.

Steam and water flow thru the fill / vent valve and into

the condensing tank, venting the chamber. There is

coiled tubing under water in the condensing tank which

serves to turn the steam back into water.

There is a pressure relief valve which opens if the

pressure in the pressure valve reaches 31 PSI (214

kPa) during a cycle. This provides a safety relief for the

chamber so that unsafe pressures cannot build.

There is a temperature gauge on the front control panel

which indicates the temperature inside the chamber

during a cycle.

1.4 SPECIFICATIONS

Factual data for the sterilizer is provided in Table 1-1.

Table 1-1. Specifications

Description Data

Dimensions (overall):

Length ……………………………………….. 19 in (48.3 cm)

Width ………………………………………….. 14 in (35.6 cm)

Height ……………………………………………. 13 in (33 cm)

Shipping Carton ………………………… 24 in x 16 in x 16 in

(61 cm x 40.6 cm x 40.6 cm)

Door Opening ……………………………… 6 5/8 in. (16.8 cm)

Weight:

With Reservoir Empty …………………….. 30 lb (13.6 kg)

With Reservoir Full ………………………… 39 lb (17.7 kg)

With Shipping Carton ……………………… 39 lb (17.7 kg)

Water Reservoir Capacity ……………. Approx. 3/4 gallon

(2.75 Liters) to full mark

Electrical Requirements:

100 VAC Unit (M7-003) ………….. 100 VAC 50 – 60 HZ,

15 amp, single phase

115 VAC Unit (M7-001, ….. 110 – 120 VAC 50 – 60 HZ,

 M7-004, and M7-005) 10 amp, single phase

230 VAC Unit (M7-002) ….. 220 – 240 VAC 50 – 60 HZ,

5 amp, single phase

Power Consumption:

 100 VAC Unit ………………………………….. 1150 WATTS,

12 amps @ 100 VAC

 115 VAC Unit ………………………………….. 1150 WATTS,

10 amps @ 120 VAC

 230 VAC Unit ………………………………….. 1150 WATTS,

5 amps @ 240 VAC

Recommended Circuit:

A separate (dedicated) circuit is recommended for

this sterilizer. The sterilizer should not be connected

to an electrical circuit with other appliances or

equipment unless the circuit is rated for the additional load.