Air conditioning question

Ted_9

I have a customer that has an American Standard Auc100c948a1 furnace with 2 zones. The zones are EWC ultra zone. I'm pretty sure this furnace is single speed and I didnt see a barometric bypass. He wants an a/c coil and condenser added.

Do I install a single speed condenser with a barometric bypass or can we add a 2 speed condenser and do we still need a bypass?

don_26

don_26

Bypass

Good morning..If I recall ewc teaches that if you design
your duct for each zone to handle 70% of the air,you can get by without the damper.
One can only know by doing the math.

As fars as the condenser a twospeed compressor or dualcomp
will need a vsd blower in order for it to work properly.
This too should be check by asking the manufactuer of the
equipment you choose.

Is it spring time there yet?

Kal Row

system designed from the ground up

for heating and cooling change the fan speed for each, much slower for heating, you will need a way to do this, most fan motors have multiple run-winding taps - so you could have the cooling relay switch it

Brian_24

If you measure the static pressure of the system with just one zone calling will be the true indicator of the need for bypass. Chances are you are going to need it. High static kills your performance. Just my humble opinion.

jim lockard

AUC / Amer Stand

Model AUC is a 90 plus one pipe gas furnace with an solid state IFC You should be able to set up to a 4 ton indoor A/C coil(TXC048) on that furnace, hook it up to an 4ton A/C condenser set you dip switchs as required on the IFC and start cooling as for the bypass is that not controlled by your T-Stat? J.Lockard

Nron_9

A little of topic
anyone doing hi-V air systems ever used the air link hi -v system by heat link would like some feed back if possible

thanks guys

Ken D.

AC

I have found a freeze-stat installed on indoor coil will give you a little wiggle room if your calculations are off a little.

Me_8

Odds are it needs a bypass very few air systems are zoned right to begin with. heat is a little (very little) more forgiving than A/C about reduced airflow. One thing any zone system should have is a sensor in the supply air to cyle both heating or cooling off if the supply duct gets too hot in heating or cold in cooling almost every zone panel has that as an option just look at the wireing diagram in the panel. As far as two speed That can take a wee bit of creative wiring on the indoor fan to get things to run right.

Ted_9

thanks for the input. I beleive it will need a bypass.

GEO_3

heatloss/gain

Don't install 4 tons just because you can handle 4 tons. Size it properly, don't excede the 4 the furnace can handle.
Set you blower speeds acording to your design specs, While most of the time high for cool low for heat works it is not always the best performance.

Ted_9

geo

Yes, we size every job included replacements. Oversizing in A/C is a problem in this country. As we all should know, over sizing does not benifit the consumer.