August 19, 2025 HVAC Condensate Drain Cleared

    Now What??? The compressor is turning off at very high and irregular temperatures, anywhere from 39.7 °F to 41.7 °F. We’ve seen some of these, but not repeated like this. Martin called a new HVAC company, Blue Valley Heating and Plumbing, that was recommended on the Rheem website. And WOW! They were able to make it out yesterday! Martin wanted to collect a full day’s data today to see if the fix worked.

As you can see, we had 3 repeated high temperature compressor shutdowns. Tony spotted the problem almost immediatly, the condensate drain was clogged up a bit. It turns out that the Rheem air handler has both a primary and a secondary drain. The water was backing up in the unit’s primary drain, until it filled the secondary drain enough to lift the float in it, which shuts down the compressor!

At long last we know what shuts down the compressor. It won’t shut down even if the evaporator coils are completely frozen, even in that condition the compressor won’t see any liquid freon coming in. The problem has always been this float valve getting tripped. The direct freeze detect is not actually detecting a freeze up condition, its detecting the compressor being shut down because the condensate line isn’t working well enough.

Once the line was cleared it ran all day today, 8/19/2025, with no problems.