GCS RTU replacement help needed

[BaldLoonie]

Got an 80s vintage GCS10-653 on a roof. These are side discharge gas packs but the air then is transitioned into the roof. Appears to be sitting on a factory curb. I'm nervous about adapter curbs, wanna be sure the supplier is getting the right one. So if anyone is familiar with that unit or knows curbs & adapters well, please pipe up.

The attachments are showing curb drawings. One came from the new unit vendor, Bryant. The modern drawing of what they think the Lennox curb is came from another vendor but for the same UT/ICP unit. The adapter drawing came from the Bryant supplier. The old drawing came from Davenet, original to the old RTU. Actually that pdf didn't work so I attached the whole GCS manual. The curb info is about 2/3 way back.

Opinions on whether that adapter curb is ok!

[BaldLoonie]

New curb adapter drawing here.

[hvacprodmgr]

John,

CDI is a reliable adapter vendor ... we use them as well as one out of Texas ..
They all have info on the old models, and provide drawings for the replacements.
My question is you state that the duct comes out the side. When you stick a curb adapter on the existing curb, you will be raising the unit as well. Is there going to be an issue with duct transitions at that point, being as most of the adapters are designed to match curb and ductwork as much as possible.
The other key is to make sure the replacement unit selection is correct, so we chosse the correct curb adapter ..
Hope that helps ..

[BaldLoonie]

Hi Don, the unit is side discharge but the air is transitioned down into the curb. So our new unit will be a downshot. CDI did 2 drawings through 2 vendors. One drawing they had the footprint of the adapter a bit smaller than this one.

[beenthere]

Sorry. I can't help you. Never ran into one that I can remember.