Pump Humming or Running IntermittentlyUpdated 3 hours ago
Pump Humming or Running Intermittently
If your pump is running intermittently, cycling on and off, or making a humming sound, your pump is in either Dry Run Protection or Stuck Protection as seen in the graphic below from the pump manual:
The Dry Run Protection and Pump Protection are often related because if the pump is dry or has air in it, that often causes the impeller to get stuck.
Dry Run Protection Only
If you only have dry run protection without a stuck impeller, it'll sound like this where the impeller is still spinning, just in cyclical bursts:
If this is happening to your pump, the impeller will still be spinning but shutting on and off cyclically. If this is the case for you, you need to bleed all the air out of the pump and Hose 1 and make sure there are no obstructions keeping water from getting to the head of the pump. If you have Modtub 1.0, please make sure the elbow coming off the bottom of the cooler is angled down so gravity is feeding water into the pump. When that is angled up, it is difficult for the pump to get the needed water pressure at the pump head.
You can also take the pump off and submerge it in water to help it get going again. Once running properly, reinstall the pump on your Modtub.
Stuck Impeller
Often the impeller is stuck as well, and if this is the case the pump will hum when it is trying to spin the impeller like seen in the video below:
If this is the case, you need to undo the front plate of the pump and clean out any debris around the impeller as seen in the video below:
When it is spinning freely, it should look like this video below:
If it is stuck, be sure to remove all hair and visible debris. You can then manually force it to spin which will often free up to spin freely again. If still stuck, you can soak it in a descaling solution like CLR and then let it dry off. Once spinning freely, you can put the impeller back into the pump and the pump back onto the Modtub.
Final Note
Almost every time we've seen this issue, we have been able to get the pump working again. It is most likely not broken, but something is causing it's Dry Run Protection or Stuck Protection to activate. If you have been through these steps and are still having issues, please reach out to customer support at [email protected].
Thanks!