Water powered sump backup won't start

Old 02-21-14, 12:52 PM
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Water powered sump backup won't start

I have a Zoeller MAX Model 503 emergency backup sump pump that was installed by a plumber 3 years ago. Recently we had a power outage that lasted for about 10 hours. While I respected the plumber's skills, I'm more of a doubting Thomas when it comes to the work of others (..I trust my own installation skills even less...). Thus I monitored closely what would happen when the water in the sump pit reached the critical level.

I watched as the water level in the pit reached close to the top and was about to overflow. The float had risen to touch the stop but failed to to put enough pressure on it to turn the pump on. I lifted the float just a bit against the stop, thereby turning the pump on. It seemed to work as it should, turning off when the level receded a few inches. However, could only get the pump to turn on by this method (lifting the float).

Any suggestions as to why the pump doesn't turn on automatically? Could it be the water pressure, or maybe the float stop should be moved down slightly?

Old 02-21-14, 03:00 PM
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We can not see your pump from here.
What type float is it?
If the sumps not deep enough the float can not rise high enough to turn on.
Old 02-21-14, 03:27 PM
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Welcome to the forums.

Your pump float is adjustable. I've left a link to the manual also and it has a section on setting the float level.

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Zoeller pump - 503 installation manual.PDF
Old 02-21-14, 06:50 PM
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Thanks for the replies. PJ, I think that's all I need to do - adjust the float, or more specifically, move the float stop down a bit so that the float pushes a bit harder on the stop. I'll post back here after I test this. Thanks again.

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