My sister in law tried to install a new thermostat and has somehow messed something up. I went over and her Trane air handler will not run. I found that the glass bus fuse beside the transformer was blown. I replaced the fuse and I still get nothing except the hum from the transformer. I...

I have a 4 ton central heating and a/c. My bathroom was remodeled and now is 66 sf. My existing flex duct to the bath is 7" DIA. Can I use a 12x4 supply boot with a 7" duct, or do I have to change the duct size? How can I calculate the size of a supply boot according to duct size?

Have a 5 ton air handler with a 4 ton condenser. Off my supply plenum I have 3-6", 1-9" and 1 10" flex runs I know they are too small. Will replaceing the 9 and 10" runs with 2-12" runs be enough so I don't restrick this handler

Hi all. I currently have a 30Amp breaker on 10 gauge wire for the air handler and heat strip. This was a new install and the local inspector seems to think that 30amps is not enough. I took a picture of the specs and uploaded below. What breaker/wire is needed to be in compliance? Any help is...

What are the minimum and optimum dimensions for the closet for an air handler for a heat pump HVAC system. This is for a 2200 sq ft residence.