Hydro-Air and A/C

Jason_13

Have a job to convert from oil to gas. This is a job with new oil furnace, Oil hot water heater heating basement baseboard system and electric hot water heater.
New system, gas h/w boiler, IWH and hydro-coil for duct system.
Question, have you ever done hydro-coil and A/C coil both on the supply side of the fan? I realize normally the a/c is on the inlet of the fan and the hydro-coil on discharge side of the fan. No room to move the A/C coil to return.
The blower is an ECM motor.

NJ, Designer

Please explain your question a little better

Bob Bona_4

I'd think you'd want a external slab cased evap for this, then the HW coil down the line. Sounds like you're keeping existing air handler. Was it solely electric coils and a blower?

Rich_49

A single coil which does heating and cooling is not something exotic .

njtommy

I think what he means is this confugeration

Hot water coil top
DX coil middle
blower/ IDF on bottom

I believe he is worried about freezing the coil. Not really a big deal just install a freeze Stat on the system and set it around 35-40 degrees.

Jason_13

Sorry for not being too clear.
My concern is as follows. I am used to having the A/C coil on the return side of the blower and the H/W coil on the supply. This job will be set up as follows.
Return from ceiling to a return air box. Blower cabinet on the supply side of air box. Exiting the supply side of the blower see's the H/W coil first and than the A/C coil. My concern is too much resistance on the supply and very little on the return.

njtommy

What manufacturer are you looking at?
What's is that static pressure of the current system?
What is the static pressure drop of the hot water coil?

Bob Bona_4

I would do the evap then the hydronic coil. Just me. Done every single day with the Trane Hyperion/American Standard TAM7 and 8's with the hw coil kit. Nice stuff.

njtommy

Off topic, @Bob Bona the Trane Tam7 nicest AHU I've ever seen. Solid as a rock

Bob Bona_4

I like the push thru design, I offer the TAM4 for "budget" situations.