Pelton Crane Venting Too Soon








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"Is Your Pelton Crane Autoclave Venting
(Throwing Water Back Into Reservoir)
Before It's Finished?"
You Can Fix It Yourself


If your Pelton Crane Sterilizer works fine for a few minutes (heats up to desired temperature level and chamber pressure) and then begins to lose pressure & starts dumping water back into the reservoir it is caused by one of two problems.

Either the Bellows or the Main Valve is not functioning properly.

PCB001 (10K)

Function Of The Bellows


At start-up, the chamber is filled with air. If air is allowed to remain inside the chamber, the higher temperatures required for sterilization cannot be reached. So it must be evacuated from the chamber.

When live steam reaches the bellows, it expands and closes off the valve and allows the system to pressurize. During the VENTING cycle everything operates in reverse. For a more complete understanding of the bellows, read our article here .

The main valve is opened, the sterilizing chamber vents through the condensation coils in the water reservoir. When the pressure is released and the air-cools, the bellows contracts to its original size.

Replacing The Bellows



Tools Needed: Flat Blade Screwdriver, A Dental Pick & A Pair of Pliers
  1. To replace the Bellows in your Pelton Crane Autoclave you must first locate it. The bellows is located on the rear left side of the unit and is connected to your reservoir. It is housed in a brass cap (approximately 1 inch in diameter which makes it easy to find.

    There should be a cut-out in the cabinet exposing the Bellows, but if you have an older unit and cannot see the Bellows, you will need to remove the cabinet.

    • To remove the cabinet, remove the cabinet screws on both sides and the rear of the autoclave. Once removed, pick up the rear of the cabinet & slide it forward (there is a 1/2 inch lip on the front of the unit that has to be cleared before you can remove it).

  2. Unscrew the brass Bellows cap by turning it counter-clockwise. If it has been on there for quite a while, you may need to use pliers to start it. Be careful to make sure the pliers are on the brass cap only and not the bellows housing. Once started, you can remove it the rest of the way by hand.

  3. Using a Dental Pick, Remove The O-ring From The Back Cap
  4. Bellows KitPlace a New O-ring over the back of the new bellows (the front is the end that comes to a point)and insert the backend of the bellows into the cap. Insert the assembly back into the opening (pointed end first) and screw it back in. **Note: We recommend replacing the entire Bellows assembly including the Back cap. The Complete Bellows Assembly is included in the Bellows Kit

    Replacement of the Bellows is a normal preventative maintenance item that should be done at least annually. If this hasn't been done for a while, start by replacing it first and then check the operation again.

    Function Of The Main Valve


    The Main Valve normally opens and closes allowing the water to flow in and out of the chamber.

    When the main valve is in the STERILIZE mode, the valve closes off the FILLING port to the main chamber and at the same time applies total line voltage to the center heating element only. The two outside heating elements are not energized in the STERILIZE mode.

    A mechanical timer is set by the operator for the duration of the STERILIZE cycle (30 minutes). Keep in mind, on most models, the timer is not a switching mechanism, it only alerts you when the set time has elapsed.

    Once the bell goes off, it is your responsibility to go back to the machine and turn the control knob to the VENTING position. This in turn opens the VENT side of the main valve and allows steam to vent back into the water reservoir.

    Once again the line voltage is divided equally by the three heating elements. The operator opens the door just slightly, resets the timer and allows the instruments to dry. When the DRYING cycle is complete, the operator turns the control knob to the OFF position, which shuts off all power and closes the main valve.

    PCV075 (17K)

    To Repair Your Main Valve:


    Parts Needed: Main Valve Kit Main Valve Kit
    Tools Needed: Flat Bladed Screwdrive & Dental Pick


    1. Make Sure The Unit Is Cool, Then Turn Off & Unplug Autoclave
    2. Drain Reservoir of water by unscrewing the Drain Cap protruding below the cabinet on the right side.
    3. Once Water Has Been Drained, Turn The Unit On It's Left (Hinge) Side
    4. On The Bottom Of The Unit You will see the 2 Brass Caps approximately 1 inch in Diameter w/Slots, on the upper left side of the base. Main Valve Cap
    5. Take a Flat Blade Screw Driver & Unscrew The Cap By Turning It In A Counter-Clockwise Direction
    6. Remove Spring & Button Retainer (Use A Dental Pick To Elevate & Remove) From The Valve Block
    7. Remove Valve Packing (2) with a Dental Pick (NOTE: If You have an older model and the packings are difficult to remove, try pushing the protruding stem from side to side with your finger. If it cannot be moved, The Valve Packing is Good & you can skip this step.
    8. Remove the O-ring From The Cap using a Dental Pick
    9. Install New Valve Packings (2)
    10. Install New Button Retainer Teflon Seat First (Protruding Button Will Be Facing You)Make sure it is seated on the stem (using your fingers)
    11. Install New Spring Making sure it is centered on the valve button post.
    12. Install New Oring into Grove In Back Cap
    13. Slide Cap Over Spring So spring is inside the cap. Push down on the cap with your finger/thumb and turn in clockwise direction until threads are caught. Completely tighted with screwdriver, making sure it is tight

      TECH TIP: If Caps Are Frozen In Place, Place the blade to one end of the slot in the cap and hold at a 45 degree angle. Lightly tap the screwdriver in a counter-clockwise direction with a lightweight hammer. Then place the screwdriver at the other end of the slot and repeat. Try unscrewing it again. Once usually does it, but if it is still difficult just repeat as above. Be sure to tap LIGHTLY. You just want to break the threads loose. The Cap is Brass (a soft metal) and can be damaged

    Once you have completed the first valve, then repeat the procedure for the second. Both Valves must be repaired at the same time and you need to order 2 complete kits. After the repair procedures have been completed: set the unit upright, refill with distilled water, plug it in, run a cycle, check for leaks and that the unit functions properly.



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