[jimbob1603]

I don't have a check valve on my setup. My place is in Alton and have not had a problem with freezing lines caused by a power outage. But, I do understand the concern; especially if you are subject to prolonged outages.

I found that the linear compressor itself is tight enough to act as a check valve. When the power fails, water enters the bubbler line; but this is not a problem because the bubbler line is well below any potential ice. The air hose leading from the compressor is connected to the bubbler line at the same 'safe' level below the ice. The water will only rise to about the highest hole in the bubbler line. So, even if the power fails and allows 12" of ice to form around the dock, the compressor just starts up (when power returns), and bubbles start attacking the ice .... no problems.

You can prove this out in the warmth of your kitchen by placing a clear vinyl air hose from the compressor into a 5 gallon bucket full of water. Make sure the hose is straight & vertical, the open end is at the bottom of the bucket, and all connections are air tight. Momentarily turn on the compressor to clear the hose of water (stand back ... you might get wet). Turn the compressor off and note the water level in the hose ..... come back in an hour and note that the water level in the hose really hasn't changed. An alternative method involves a drinking straw and a 12oz gin & tonic! lol? Works the same way in the lake ..... the key is to be sure the connections are air tight and the air-hose/bubbler line connection is below the level of any potential ice.

Next best thing to a crank-up dock!