The Stack Overflow podcast is back! Listen to an interview with our new CEO.

Questions tagged [hvac]

(Heating, Ventilating, and Air Conditioning) For questions about installing, repairing, and troubleshooting HVAC systems.

Filter by
Sorted by
Tagged with
1
vote
1answer
52 views

A/C Fan won't turn on outside after replacing capacitor

I know this is a DIY stack exchange, and to be forthright, I did not DIY this initial repair because I was intimidated by replacing a capacitor, so I called a recommended technician who did the job ...
2
votes
2answers
69 views

Central AC Unit - Intake is very cold

So my central AC unit started doing something that I have not experienced before. Once the AC stops, cold air comes out of the intake vent, like really cold air. This has lead to ice forming on the ...
1
vote
1answer
59 views

Why the noises in the new furnace?

A company installed a new HVAC system 2 weeks ago. The furnace model was new: 58TNOA110C21–20. I initially ordered 58CVA110-20 but they said it will be out of market soon in August. So they installed ...
2
votes
1answer
80 views

Competing conditioned/combustion air flow; worry about CO?

My home has a partially-below grade basement that has a "Wave" ventilation system that brings cool, conditioned air in from the main house. The basement has an equipment room containing an oil burning ...
1
vote
0answers
78 views

The new AC doesn't cool the house down like old unit, what can be the problem?

I had to replace my old HVAC because it was old and had a freon leak. The new unit doesn't cool down the house like the old system. The ac runs all day and it takes hours to get down to 72 degrees and ...
0
votes
1answer
39 views

How to retrofit existing kitchen exhaust fan

I'm remodeling a kitchen that is circa 1940's. In the kitchen is an exhaust fan that sits inside a 3.25x10 duct. I would like to keep an exhaust fan in this location and re-use the existing duct, ...
0
votes
0answers
20 views

Spacing between supply line/cold air return

Is there a minimum spacing that should be followed when installing a new supply line into a room? I'm remodeling my basement and have two supply vents in the ceiling, but wanted to add 1 or 2 near ...
2
votes
1answer
58 views

Another “How do I add ”c" wire to boiler for Nest

I have tried searching this forum and others, but I could not find anyone with a situation like mine. I thought it better to ask here, rather than damage something. I have a Lennox wall mounted ...
1
vote
1answer
25 views

3-zone HVAC (HZ432) one zone's a/c stops working when hot in afternoon

I have a 3-zone HVAC. All 3 zones a/c worked fine until recently. Now, in the morning, before it gets too hot, all zones still work fine. But in the afternoon, when it gets hot, the a/c to zone 2 ...
0
votes
1answer
54 views

New HVAC installed [closed]

I just had a new HVAC system installed and the contractor installed in on a pounding raining stormy day. I am thinking that was a bad decision on his part. Now my home has a musty smell and air ...
0
votes
0answers
27 views

Door to AC unit causing pressure change?

Found water in the bottom of my AC unit inside. When I remove the bottom door the water will run back to the drain. But when I put the door back on, the water is being sucked down by the motor. There ...
1
vote
0answers
34 views

Furnace blower cutting in and out during A/C use

Backstory: I fired up my air condition for the first time this season (single family house) and felt lukewarm air coming out of my ducts. When i went outside i saw that the condenser was not turning ...
1
vote
1answer
41 views

Running AC/Heater when washing a cleanable filter

I have a heat pump/AC system with a washable air filter. I was told to clean the filter out and run water through it once a month. He told me to let the filter dry for 3 hours before replacing it. I ...
0
votes
0answers
12 views

Hvac condensate line not draining, New ac system

Hi so I just purchased a house. It was a bank foreclosure. The bank installed a new ac unit. The ac wasn't running in day one. I figured out it was bc the condensate line wasn't draining properly. The ...
4
votes
3answers
159 views

Is there such a thing as a DIY heat pump or mini split

I wanted to ask this question to the community. Is there a legal way to install a mini split or heat pump without having an EPA license? I have seen similar questions asked several times or ...
1
vote
1answer
33 views

What's the easiest way to trace out existing HVAC ductwork without cutting into the walls

I recently bought a multi-story house with a 4 zone HVAC and only one of the zones works (it just heats/cools the entire house as one zone, and the one working zone is for a small foyer which is ...
0
votes
1answer
25 views

Window air condition location placement question

1800 sqft + basement On main floor 2 window air conditioners 19k btu combined Upstairs 1 5k btu air condition There is 3 bedrooms upstairs, does it make sense to jist pit all the ac units upstairs ...
0
votes
0answers
55 views

HVAC Exhaust Routing Question

Just wondering if I could get some advice on the optimal way to route the HVAC Exhaust piping. Enbridge replaced the supports underground and before they turned the gas back on they did an inspection ...
1
vote
0answers
27 views

Separate Thermostats for Heating and A/C

I recently purchased a vacation home that has two thermostats for a forced hot air gas furnace and a separate A/C unit that shares ductwork. The A/C also cools better when both the A/C and furnace fan ...
1
vote
0answers
84 views

Does cabling between a mini-split indoor and outdoor unit need conduit?

I am installing a mini-split AC system where there are multiple indoor units connected to a single outdoor unit. For each indoor unit, there is a separate 4-conductor cable that connects to the ...
1
vote
1answer
41 views

AC Condensate Line Location - Outside vs Inside

I'm installing a few mini-split AC units in my house, and I'm trying to determine the best place to run the condensate line. Right now it's either between running it outside with the line set and tray ...
0
votes
2answers
82 views

Why would my HVAC blower motor stop working after 10 minutes of runtime

my 2 year old unit it freezing after it’s been running about 10 minutes. I turned the unit off all last night. This morning I took a look at it outside, then went back in, turned it on, sat by the ...
0
votes
2answers
56 views

Can the wire from the y terminal on thermostat be connected to the c terminal on heater board as pictures show?

My nest was installed with no c wire and it lost power. At this point the tech looked at the wiring diagram in a/c unit outside but I do not know what he did. A/c worked but later nest had no power. I ...
1
vote
1answer
36 views

Install a Wi Fi thermostat

Trying to install a WiFi thermostat. I have the unused blue wire which I believe is the common wire. It is unused both and the furnace level as well as on my current thermostat. However there is ...
0
votes
0answers
41 views

Installed NEST thermostat heat works fine, AC compressor comes on but no fan on AC unit

I installed a new NEST thermostat last fall so only used it for heat so far. When I went to turn on AC, compressor came on but AC unit fan didn't. AC worked fine last year. Could this be a NEST ...
0
votes
2answers
103 views

Can I put a 20Amp breaker on a 55 amp line for an A/C unit?

I have an unused 3 wire 220V 55 amp circuit from the meter from my old A/C unit running right where I need a 20 amp 3 wire 220v, is there a way to reduce the circuit, put in a remote 20 amp breaker ...
1
vote
0answers
38 views

Dedicated 240v 30A Circuit Switched for A/C and NEMA 14-30 [duplicate]

I have a dedicated 240 volt circuit that's hard wired into my air conditioning unit. The circuit has a 30 amp breaker at the main box and another 30 amp breaker on the wall next to my air conditioner....
2
votes
1answer
31 views

How do I determine where to connect a new C wire inside my furnace when no control panel or wiring terminal exists?

I am replacing my existing thermostat with a new smart thermostat that requires a C wire connection and the old unit did not. I intended to utilize the unused Blue wire which is not connected on ...
0
votes
0answers
39 views

air handler not turning on

Assume an ac compressor doesn't work. Will the air handler still come on if the thermostat is set to fan "on"? Does this differ system to system? I am trying to troubleshoot a non-responsive ac ...
1
vote
2answers
178 views

How do I deaden the sound of water dripping on metal?

I live in a two story apartment complex (upstairs neighbors are REAL nice). My bedroom has an AC Box/Swamp Cooler mounted into the wall. Directly above it is a similar unit for my neighbors. The ...
1
vote
1answer
83 views

Best air conditioner for cold blasts?

The old air conditioners I had could blow out snow literally that is how cold they got, now air conditions are only moderately cold. What would be the best system to get to just blast one giant vent ...
0
votes
1answer
64 views

Why is my AC only blowing out Ice cold air and freezing over AC lines?

I've had a company come out and tell me the ac and furnace are ran from 2 different fans and they recharged the AC unit. However, prior to this the AC was still freezing over the lines. If I have the ...
0
votes
0answers
45 views

Wand or 2 foot long stick between my master bath fan and outdoor flood lights connecting to share wiring for power?

I'm divorced. My ex husband had a guy install a junction box on corner of house to spotlight the swing set years ago. Recently I was in the attic and discoved a 2 ft "stick' or "wand' that was quite ...
1
vote
1answer
56 views

Line to AC dripping at the furnace

My line from my exterior AC unit is dripping at the furnace. The dripping over time has caused rusting and we've had to replace the control board under it. It appears the root cause of the problem ...
0
votes
1answer
75 views

Air Filter size for (new to me) home HVAC

My wife and I just purchased / moved into a new house and I was going through each of the systems and found the HVAC filter, it was literally destroyed (it had filled with crap and crushed itself in ...
0
votes
0answers
28 views

Rough in bathroom exhaust

So, I have a pretty basic question that I can't really figure out for some reason. Is there a way to rough in bathroom exhaust fans before siding? In other words, there are trim kits for sconces, ...
0
votes
0answers
23 views

Side venting range hood through a chimney

After many painful design revisions to update a kitchen built in the 1920s, I think I've finally got it down. One of my challenges has been being stuck with the location of the stove/oven, because ...
3
votes
1answer
57 views

Furnace Connect G Wire

I have a dual energy electric/oil furnace that is wired to a thermostat with 2 wires R and W. I don't have any AC. Inside the furnace there is a switch relay to control the fan but it is not connected ...
0
votes
2answers
57 views

How to clean a reusable HVAC filter

My HVAC system is around 15 years old and I have a washable air filter. The tech who looked at it last told me to clean the filter out and run water through it once a month. He told me to let the ...
3
votes
1answer
127 views

Can I change an orifice to make an R22 evaporator unit compatible with a 410a unit?

I have an R-22 system that was never hooked up or run. It was put in place and then the project was put on hold for several years. The outdoor condenser unit is no longer available obviously. We just ...
1
vote
1answer
56 views

Ductless AC Initial Charge

I just purchased an LG mini-split set: 18,000 BTU indoor unit https://www.supplyhouse.com/LG-LSN180HSV5-18000-BTU-Ductless-Standard-Multi-F-Air-Conditioner-Inverter-Heat-Pump-w-Built-In-WiFi-Indoor-...
2
votes
1answer
28 views

AC Unit Not Cutting On

My AC unit has the thermostat indoors, a unit in the crawl space and the outdoor unit. Everything was working until I had a contractor come out and add insulation in my crawl space. Now the heat/air ...
1
vote
0answers
33 views

Problem connection C wire into Lennox Furnace

I would like to connect my new Honeywell WiFi thermostat (RTH6580WF1001) to a Lennox Elite dual Heater and Cooler system. I don’t have a C wire in my old thermostat. I have read online that I can ...
0
votes
1answer
19 views

coleman/york furnace 7 red flashes

My furnace "fails to start" 3 times, then it flashes 7 beeps and quits trying. I can hear it start then the flame "just stops" 3x in a row. What gives?
1
vote
1answer
59 views

Flexible round duct - What to use

I'm re-routing some 10x3.25" duct through a bulkhead in my kitchen. Planning to change over to 6" round duct for a 4' segment that is relatively straight (no 90s). It was my intention to use non-...
0
votes
0answers
30 views

How can I hot wire my AC unit from my furnace without a hot red wire?

My power control board inside my furnace seems to be broken and a service technician cannot come out until after the memorial day weekend. My thermostat is not receiving power. Using a multimeter I ...
2
votes
2answers
231 views

Unthreaded holes for AC fan motor mounting screws?

My AC is not working. It is a Trane AC (Model 2TTB0030A1000AA). In the process of diagnosis I tried replacing the capacitor, and that did not help. I tested the fan blades and they no longer spin ...
2
votes
1answer
42 views

Do any home thermostats have an adjustable control range?

I am having trouble with AC and need to replace it soon ; so I have been listening to it cycle .I knew it only stayed on a short time but I just found it runs less the 2 minutes ; that is with ...
0
votes
1answer
69 views

Sealing a closet door that has a gas fired water heater in it

Does anyone know how to make a self sealing door? There's a bedroom in my basement, and it has a door in there that allows you access into the HVAC room (which can be entered from another door in ...
0
votes
0answers
29 views

Air conditioner will not shut off

I cannot get my air conditionar to turn off at the thermostate. I turn it to off or auto and it still runs. I have to flip the breaker off to get the unit to turn off. What could be wrong?