Anybody know anything about heat pumps? Every since we have lived here at random times I will wake up in the morning and the inside unit is running, temp is below set temp, outside unit is not running and the breaker for the outside unit is tripped. This breaker also controls the inside aux heat strips because even though the inside unit is running and thermostat is calling for aux heat, no aux heat. When I reset the breaker the aux heat will then come on. The outside unit will be on lockout mode and won't start on its own so I have to remove a couple of screws to get to the control board. The unit will be frosted up and the led light on the board is flashing the code for low pressure lockout. What I then have to do is take a flathead screw driver and jumpers the defrost test leads which will clear the code and fire the unit back up. I then have to jump the test leads again and this forces unit into defrost. It runs thru and defrosts the unit, then goes bad into normal until the next time it does this.
My theory is that for some reason it is randomly not going into defrost so the into ices up, which then causes the compressor to draw too many amps along with aux heat being active and trips the breaker. When you power it back on the systems maybe sees low pressure and locks it out. The test for the defrost board is if you jump the test leads and it goes into defrost mode the board is good. If you jump the leads and it does not go into defrost the board is bad. It surely has something to do with the board or maybe the sensor that senses when it is time to defrost. The thing that gets me is its at random but always overnight when it happens. It has already done this once this season and that was about 3 weeks ago maybe. I have caught the unit in the middle of a defrost cycle on its own so it seems to normally work, and I find it hard to believe anyway that the unit would run for weeks at a time and not have to defrost. So defrost is working for the most part but at random does not wor k and starts this series of events. So, anybody have any thoughts? Sent from my iPhone _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
