How To Tell If A Dump Valve Is Bad July 05 2015, 2 Comments

As part of our Troubleshooting Manitowoc Ice Machine Series, we will be visiting the water dump valve, found on almost every Manitowoc ice machine made. These valves are extremely common and only come in 2 different varieties. That's right, every dump valve on every Manitowoc ice machine is only 1 of 2 different parts, either 115v or 208-230v. This brief post will share the best way to diagnose the dump valve.

First, the two different dump valves are Manitowoc OEM part number 000001767 for 115v ice machines and 000001768 for 208-230v ice machines. We keep both ice machine parts in stock and are available for standard and rush order shipping. They are also very easy to change, almost anyone can swap out a dump valve on a Manitowoc or Koolaire ice machine.

Symptoms of a bad dump valve

When a dump valve fails, it will typically stick open. This means, that even though you can see water coming into the water trough, it never actually fills. Thats because while the dump valve is stuck open, the water will continuously go down the drain. A stuck valve can also describe a valve that has a plunger that has deteriorated and no longer seals, not just stuck in the open position.

Cloudy ice could be the symptom of a bad dump valve and is the inverse problem as described above. Manitowoc ice machines will most always purge the water trough before making ice. This process includes filling the trough with water, before the freeze cycle, and then dumping the water down the drain. This allows the ice machine to flush minerals out of the trough. If the dump valve will not open, then the water never flushes and the minerals remain in the trough, so when the ice starts to freeze, it's cloudy with minerals.

How To Diagnose a Stuck Open Dump Valve

It's easy, disconnect the ice machine drain, careful not to make a mess. Start the ice machine and watch the water flow out of the ice machine. During the freeze cycle, once the compressor is on and water flowing over the evaporator, no water should be exiting the ice machine. If you notice water flowing to the drain, throughout the freeze cycle, the dump valve is stuck open.

How To Diagnose a Stuck Closed Dump Valve

Inspect the water trough during the startup cycle. Water should fill the water trough, then quickly purge down the drain. If you do not notice water actually leaving the trough, this indicates the valve may be stuck closed. If your specific model ice machine is currently calling for a purge, there should be voltage to the valve. A dump valve is normally closed and will only open when voltage is applied.

Manitowoc Dump Valve Conclusion

The dump valve is a very common part to replace. Water is constantly going through the valve and during the purge cycles, it's opening and closing. To replace, it takes nothing more than a socket and phillips screw driver. If you have questions diagnosing your Manitowoc or Koolaire dump valve, please contact us via email at, we are happy to help.

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