AC compressor randomly not turning on

Started by Suef, March 26, 2025, 09:30:59 AM

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Suef

We are really stumped about our AC. They replaced the condenser outside unit and coils in attic 6 mos ago. American Standard 13 ton)  They left the old zoned thermostats (3 zones master bedroom area is main/master?? zone). They left the dampers, and the old control board up in attic too. We replaced  the condenser/coil when the outside unit would randomly not turn on thinking that would help. The blower in the attic would turn on fine.  So we thought maybe we had a slow leak in the coil and it was freezing over and that would fix it. But it didn't and now it's still happening with the new system the same thing plus more stuff.

Sometimes the compressor and fan both work fine whole system is great. Sometimes it's hot in random rooms where the thermostat calls for 70 and it will be 72. But the other two zones are holding temp. Monday night it was the bedroom zone not holding temp and then yesterday it was the family room zone. The blower running all night trying to get that zone cool.

Sometimes the compressor turns on fine then later that night at bedtime it won't and it's just the attic blower working.  We turn off the breaker then turn back on after a short 1 min wait and then it starts fine sometimes. Sometimes we just wait a few hours and it comes back by itself. Other tines even when we reset the breaker the condenser won't turn on. Then in the morning it turns back on. They've checked Freon this week and it's fine. As well as a drain valve? was clear.

Is it a bad control board? The zones thermostats not talking?  Or is there a valve or switch somewhere that makes sense why the condenser outside is being so random? Any ideas? It's an