Anyone run into this? A friend has a Heil unit that runs non stop all day. Around 5PM it shuts down for 4 hrs then comes back on. The 4 hr shut down codes are "high pressure lock out, low pressure lockout or suction over temp lock out". I have not actually seen the unit but multiple techs have gone and could not figure it out. My guess is that (being an old brick house with not great insulation) the unit is actually slightly undersized; it won't fully satisfy all day because of this and so it shuts down for compressor safety. Any thoughts?

Posted by Beavertron5000 at 2025-08-07 17:25:32 UTC