2 evaps, one condenser

heatboss

i have a light commercial application where were installing 2 downflow gas furnaces and the area needs 5 ton of air, but since this is upstate new york it doesn't need the full capacity all the time, so i'm thinking of installing one 2 stage 5 ton condenser and 2, 2.5 ton evaps. has anyone seen this done correctly, or can it be done? i've done it with refrigeration but never with a/c.

unclejohn

You need to make sure what the capacity is on 1st and 2nd stage. Most compressors are 70% and 100%. You would be better of with two 2.5 ton outdoor units.

ratio

I've installed Trane TSA dual compressor units with one evap, but I don't think they are available that small. Maybe a Rawal thingie'll work for you.

I like staging twinned units, it generally comes for free on the heat side. The Rawal device should let you turn down a single stage compressor, maybe via a solenoid valve on one evap. I don't know how it effects efficiency.

njtommy

Here's what the Rawal looks like.

njtommy

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ratio

@njtommy, nice, pain in the you-know-what to get it in there? I installed one on an RTU where the injuhneer forgot to order the VAV airsource with hot gas, but it was all right there, I burned it in sitting down. I'm considering one on a three ton split for low load.

unclejohn

Your dumping hot gas into your compressor and then dumping liquid into to it cool the hot gas. No thanks. Two 2.5 ton units will be your best and most eff. operation.

njtommy

This was a pretty big Lennox condenser. It was no problems getting it in terms of fitting it size wise.

If you want to see something cool check out Kramer thermobanks.

SWEI

njtommy said:

If you want to see something cool check out Kramer thermobanks.

Very slick.