Hey /hvac/, I've got a mystery that only you can solve. My house gets really cold upstairs, and is hot as hell downstairs. I'm in a two story, 1400 sq ft house in Florida, with central air. We usually keep the thermostat set at 75 degrees, and while the upstairs will be a nice cool 75, the downstairs will be up at 80 with no air flow. I recently changed the filters and noticed that while the upstairs intakes (two 12x12, one 20x20) were sucking in plenty of air, the one 20x20 intake downstairs wasn't sucking in at all. Why is this happening? More importantly, what do?
Oh and the thermostat is upstairs which I'm sure has something to do with something. Seems like a weird place for it since the only thing upstairs is the kids' bedrooms... Why would they put the thermostat upstairs?
>>1000060
Maybe check the groundfloor intake?
Seriously, use a telescopic cam or just stick a smartphone/digicam/gopro to a firm piece of wire and check, maybe birds built a nest or whatever.
>>1000062
>>1000063
>>1000077
3rd thing. Kek, i really need to read the important things -->
The thermostat is measuring the temperature in the room it is located.
(trust me i am an electrician)
Soo if it reaches the temperature which is set, it stops. I guess you knew this. So maybe try to cut off the room from the rest of the house (close the doors and windows) and see if you could reconfigure or if this has an effect on the cooling system.
Did you bought or build the house? I guess first choice.
>>1000083
The ground floor intake is clear. Hardly even any dust in there, the house is only ten years old.
Tried a candle, the smoke isn't pulled into the duct; absolutely no airflow. The downstairs cold-air vents have some, but not much, flow.
Thermostat is in an upstairs hallway, no way to close it off. And I rent, so I can't afford to call an HVAC guy unless the landlord will pay for it... which he won't.
>>1000060
is any of the ductwork exposed? there may be dampers you can use to redirect airflow. usually the problem is the other way around since cold air falls but if all the lower level vents are closed off then its never going to get cool especially with the thermostat upstairs.
tl;dr find whats blocking the return air on the lower floor
>>1000165
Thats an good idea.
Also try to close every door and window and just open one small window so the air must flow and the only way in is the ground intake, and if there is still no airflow the intake must definitly be blocked.
Look at the pic, maybe it is clogged at a point you can't see/reach.
Make some photos of the intake
>>1000060
WE WUZ CLOSED DAMPERS AND SHIT
>>1000060
#1 Highly unlikely upstairs reaches set point before downstairs. Remember hot air rises cold air sinks. So my guess is someone before you said it's way too hot upstairs they shut all the dampers to the first floor and opened all the dampers on the second floor find them change it success.
>>1000408
This sounds likely. Where are these dampers usually located? Attic, maybe?
>>1000441
Do residentials intsalls even have dampers usually? He probably meant registers, the things in the floor/wall/ceiling that the air comes out of.
>>1000060
>the one 20x20 intake downstairs wasn't sucking in at all. Why is this happening? More importantly, what do?
I did hvac for several years, there is a good chance that your duct work could be damaged or not attached at all. Depending on who did the install you could have dampers closed off (as other anons have suggested). If you have access to your main unit you should go check it to ensure your connections are good. If your dampers are located on the unit you can adjust them there.
Fix your return air downstairs. Move your thermostat downstairs. Get a ceiling fan. Problen solved.
