Replacing 120k btu LP Carrier 5 ton AC unit looking for the best option

Nland

House has very high ceiling this is for the lower unit i am thinking dual fuel
i was looking into the 20 seer trane but then people are telling me anything over 16 seer when they have issue's it can be pricey. A few people have suggested Bosch? we are in the DC metro area so it does get cold but no that cold the ac has always worked fine the heat is the issue any thoughts

EBEBRATT-Ed

Need to know what type of equipment you have.

Furnace with an AC coil??
Packaged unit??
Heat Pump ??

JUGHNE

How big a house is this?
120,000 btu and 5 ton AC for just the lower unit sounds like a lot.

Nland

Its currently a carrier 2006 92% LP with a 5 ton Ac ive been told its the worst model Carrier has ever sold. the 2ndairy manifold was replaced 3 years ago there was a class action suit against carrier. now it starts up but once it reaches tempature if you increase it goes throught the lock out shut it down wait for 10 minutes usually it will fire up

The house size is about 4,686
Total SFLA (Includes Fin. Bsmt) 7,136 sq feet has a 4 ton LP in the attic

pecmsg

Get a Manual "J" Heat load / Loss performed first.

Second find a contractor you can trust. There more important then the name on the boxs.

Nland

Just want to stay away from Goodman. I get it to find a trust worthy installer thanks

pecmsg

Nothing wrong with Goodman.

The installing contractor makes all the difference!

JUGHNE

Just a WAG that the attic furnace is 80-100 input, then your numbers fit into the back of the napkin heat loss/gain calculations. (the basement loss/gain counts only a fraction of the rest). That napkin form guarantees the installer will always CYA for sizing. I know, having done it myself....always oversized!

Your problem furnace; does the burner run constantly until T-stat shuts down....or does it cycle on high limit before reaching set temp?
Then when you turn T-stat up the next burn cycle will again trip the high limit....only you notice it now.

Often there is a problem with duct work sizing, especially return ducting. 5 ton AC should have 300 square inches....about 30 X 10 supply. The return should be about 400 sq inches, 40 x 10 ductwork.

mikeg2015

Definitely get a heat pump. SHould be cheaper to operate above at least 20F, maybe lower, which is most of the season.

Depending on the overall setup, might be able to use a 4 ton 2 stage with 2 or 3 zones. Would really increase comfort and even heating.

Nland

Your problem furnace; does the burner run constantly until T-stat shuts down....or does it cycle on high limit before reaching set temp?
Then when you turn T-stat up the next burn cycle will again trip the high limit....only you notice it now.

Great question i will check to see if its shutting down prior to reaching temp yesterday i shut it off for 10 minutes then bumped it to 71 from 66 to 71 it did fine its still intermittent .

Are zones similar to dampers because the basement is completetly finished the only place to add a damper the main trunk directly above the Furnace

Nland

Now i am being told that the current system is starving for air and i need to raise the new unit on a box so the that the 2 returns bring in more air

JUGHNE

What size is the air filter for this now?