home A/C, HVAC guys input needed here.
 

I have got a new place to live now :cool: its a 2100 sq ft two story with a living room that has tall celings.

The A/C unit is one item but the airhandler in the attic has two outlets which are going into two manifolds which air the lower and upper floors of the house.

The manifold air ducts have got electric dampers in them (which are a bit impossible to reach at this point of time due to me being a bit wary in fiddling with the attic. The dampers are controlled by a unit stuck to the handler furnace and is branded as trolAtemp

anyway - the 1st floor air registers blow really hard, almost if all air flow is coming out there, the upper floor has really poor air velocity out the registers - almost impossible to feel even at 2 inches from the registers.

Is this setting normal for cooling - or should it be the other way round.

Hot air goes up - hence upper floor is not as cool as the lower floor where there is a lot of cold air and a lot of air velocity at the registers.

there is a thermostat in the first floor too but it does not make much sense to me - its an old mercury bulb type - it does switch on the A/C if I manipulate it - but it was very dusty and set to 90 - so I left it there too.

From the description it appears that the upper air supply damper is closed and the lower air supply damper is open. The dampers may not be operating correctly and the assistance of an HVAC controls tech will be required to sort it out.

Generally it's best to have most of the supply air delivered to the upper level where it's hottest as cool air will naturally sink to lower levels.

Where are the grilles for the air going back [return air] to the A/C unit air located?

Blow the dust out of the thermostst for it to operate correctly.

Yes I also believe the upper air supply damper is closed and not responding.I have talked to a few guys but being summer - they have a selection of answers.

1 - system is too old - you would prolly need a full unit
2 - booked till end of september
3 - something else too.

thanks for the answer tho.

Im going to dig into the system and see if the damper is getting voltage or not

there are two return vents - one is on the upper floor and is 20x30 inches, the other is a 15x15 inch vent and is on the lower floor - the upper floor vent is placed such that it can be seen from anywhere in the lower living room.

Just going on feeling comfortable or not which floor do you prefer or are they both the same?

Would not surprise me if one of the thermostats controls predominately air distribution if system is working properly.

Where in TX are you? I have a AC guy who charges $25 for a service call for diagnostic. Used him once and he seems pretty legit to me.

Where in TX are you? I have a AC guy here in the DFW area who charges $25 for a service call for diagnostic. Used him once and he seems pretty legit to me.

Does the upper return vent seem to be sucking air as strongly as the lower one? You can temporarily block either with a newspaper or something to see if the other is sucking.

The other obvious thing is to be sure the stat for upstairs is calling for cool so that it opens those dampers. Switched to 'cool' and turned down. Does cranking it either way have an effect?

Temp aid to equalize is block half the lower return forcing more of the conditioned air to pass the upper level.

That's a good start to finding out what is supposed to control the upper floor damper. Usually each zone has a separate thermostat to control that zone's damper, which opens the damper when the temperature is above the set point.

The biggest return vent is on the upper floor, so that's OK.

Im in Houston

I am going to trace out the wiring for the upper stat, the lower one only has 3 wires in it, Either the thermostats are tied in parallel or the damper settings for lower and upper are reversed.

For the time being I have mounted three little black honeywell fans on the walls facing upwards which actually caused the upper floor to cool down real quick and the A/C then shut off. The fans look a bit cartoonish according to the Mrs.

There is no change at all in airflow with the stat set to heat either.

Never mind. Pretty sure he will not drive down there. lol

It's a box with a flapper valve in it. If you had to you could hook up a heater cable from the junkyard.

If you bought the place - I'd look at my heating and cooling usage/bills to gauge whether I wanted to do an immediate R&R of the whole HVAC system. I don't think I could calculate how many times the new HVAC system I installed in my present home over a decade ago has saved me in power costs. Most any two-story will benefit cost wise over time from dual-systems, independent one another. -If you even use the second floor? Of course this all depends on your time horizon in this home too.

It also helped greatly Upping my home's attic R-value from 12 or 13 to R-45. As well doing an install of ridge-cap venting along the entire apex of the roof.