HVAC question...or two

Remember that the inspector is an expert on his interpretation of the code book.

Probably more accurate...
 
Thanks again for all the help and time you guys have spent trying to figure out someone else's problem's
 
hunterdan said:
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Also talked to the inspector today about a number of things. I asked about air barrier and he said my wrap on walls and roof will suffice.Also asked about T&G on walls and he said my idea of caulking all the joints between runs and around wall perimeters would be ok especially if I was going to laquer the walls.

looks like nailing a 2x4 directly to the 2x12 rafter would give me 12-3/4". baffles (2") + insulation (10.25") equals 12.25"
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Yeah, I think you're on the right track. If you do the 2x4" furring, don't lay the 2x on the flat. Rip them in half (1.75" total height) and install them flush with the joists above. If they're laid on the flat, they'll pinch the insulation.

The roof underlayment shouldn't count as an air barrier, since it's outside of the thermal envelope. I did find in the NCRC where they would allow for a T&G ceiling if you installed it over a taped & sealed vapor-permeable air barrier, so you could still do the wood w/o GWB if you're dead set on it, at least by code. Once you punch a few hundred holes in the air barrier, I wouldn't expect it to perform to spec, but it is "code-compliant".
 
Back to HVAC... OK, the fella who installed the heat pump did install the air handler,ductwork,condenser and ran wires for both thermostats. After that he said I'm done til you get power and we start the system.
Now i'm trying to get ready for rough in inspection and I believe I'm supposed to have the wire run to main for condenser/air handler including interrupts for each. I called the hvac guy and told him I need that stuff completed. He says that's for me to do and he does not mess with high voltage only low voltage final wiring. I said well my contract says turn key...He replied well I can maybe try and help you figure it out next week...

What say you guys? I can see the UL stickers on both units. Air handler says max fuse or breaker 15amp but it has 10KW heat strips. Air handler does have a 60amp breaker on the side of it. Can that be considered the interrupt if it cuts power at the unit? Condenser says max breaker 40 amp.
 

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Most smaller hvac contractors do not have an electrical license and that is often done by a third party as it would require a separate permit from the hvac permit. Maybe it’s covered under the electrical permit you already have pulled.

Edit: depending on what y’all agreed on in contract may determine who pays for that third party.

I’m assuming air handler has one connection for power as is normally the case, You would wire air handler and size breaker to meet the needs of the heat strips. So number 6 copper wire and a 60 amp breaker for 10kw. Ignore the 15 amp if using heat strips. If the air handler and heat strips power separately then size wire and breaker for each accordingly.
 
Far as outdoor unit goes I’m pretty sure by code you can size wire to the minimum circuit amps which is 24. So that would be number 10 wire. But in my mind if I’m installing a 40 amp breaker I want wire that can handle 40amps. So that would mean number 8. The breaker is little larger to handle inrush amps of compressor on start up but once it’s running continuous amps will be less than the minimum circuit amps.
 
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