AC/Heat not working! Help...

[aces11]

Hey everyone, hoping I can get some help here, I'm sure I can, you guys are great. Last week, out of nowhere, my heat stopped working. Fan still runs, but can't get AC or Heat to work, just the fan. Where should I start? It's a natural gas, rooftop unit. thanks again.

[HayZee518]

check filters first. next pilot if it is a standing pilot. if the pilot doesn't stay lit, the flame detector or thermocouple cappillary tube connected to the main valve.

[aces11]

ok, the filter is fine. Found a guy to come out and do a free estimate, and after about an hour, found a leak in one of the tubes on the outside of the core? He said to repair it and fill the system back up, we're looking at $375. thoughts? Can't really spend that much right now!

[HayZee518]

the a/c unit uses a reversing valve. when the unit calls for heat the freon flow is changed through this reversing valve. what once produces cool air is now passing heat into your living space. the gas burner is just a back up for extra heat for the unit. $375 isn't bad for fixing a leak and replacing the freon. If he doesn't braze the leak then he'll be using a special epoxy repair patch that will last. as far as the refrigerant used it may be r-22, r-12 or r134a. The previous two are expensive as they are regulated by the epa.