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Questions tagged [hvac]

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

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1answer
41 views

Two HVAC units on one condensate drain line

I am renting a house with two HVAC units - one upstairs and one downstairs. There were two condensate drain lines (one per unit). The units were older so when they quit working efficiently the ...
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0answers
11 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 ...
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1answer
31 views

Blower Motor Heat and Cool Control Board

I’m an electrician by trade but i have a friend who needed his blower motor replaced. The parts store sold him a motor but it only has one hot leg. The control board has a hot for cooling and a hot ...
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1answer
172 views

Can I terminate ah HVAC condensate drain line through a soffit?

Problems with running attic condensate line drain out the soffit on the side of the house (3 floors up)? Condensate line is leaking and I'm trying to avoid destroying walls to find the leak.
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2answers
81 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 ...
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0answers
32 views

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

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....
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1answer
64 views

Old thermostat to Hive thermostat

My wife decided we needed a smart thermostat... which means I need to install said thermostat... Currently a Bryant Evolution series is mounted. She purchased the Hive with Hub when it was on sale. ...
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1answer
16 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 ...
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0answers
16 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 ...
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2answers
89 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 ...
2
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2answers
188 views

Lennox G23Q3/4-100-2 And Ecobee4

**Pictures attached to go along with my rambling explanation I have my Lennox G23Q3/4-100-2 natural gas furnace and my central air system that has been working since 1995 on a basic programmable ...
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1answer
59 views

How can I prevent makeup air vents from exhausting conditioned air?

The utility room has two 8-10 inch ducts running to it from the exterior of the home. There are also three fireplaces in the home, and we have noticed that occasionally the house smells like smoke, ...
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1answer
65 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 ...
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1answer
27 views

a/c condensation line not draining

I have a unit that is installed in the attic and is about 2 years old. For the first year everything was fine and then one day it wouldn’t run. So I hooked up the shopvac and sucked the condensation ...
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1answer
50 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 ...
3
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1answer
40 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 ...
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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 ...
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1answer
84 views

Which humidistat terminals should I use for my humidifier?

My Carrier furnace does not have a humidifier connection on the control panel. I have two wires from the humidistat. Do I use W-C or R-C connections for a normal operation?
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1answer
58 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 ...
1
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1answer
46 views

2 Air Filters in Air Conditioning Unit

My air conditioning system has a 2-layered (each 1") filter holder, definitely made for two filters. My idea, to improve the filter life and have the least air flow restriction, is to have the initial ...
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1answer
31 views

C wire in wireless Thermostat Transofrmer question

I have a rheem handler with a 46-23115-02 transformer. I do not have a C-wire connection that I can see. I have a 5 wire cable... so I do have a blue wire available that I can connect as the common ...
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1answer
43 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 ...
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1answer
43 views

HVAC blower fan won't stop

FINAL UPDATE: I have found the culprit - the Nest thermostat itself. First, I disconnected the t'stat at the control panel and found out that the fan would no longer start upon powering the system. ...
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5answers
29k views

Can a homeowner without a Section 608 EPA license legally connect his own gauges to his own air conditioner if the unit uses 410a refrigerant?

It has been suggested by at least one moderator on this site that EPA Section 608, which restricts who can purchase and handle refrigerant, including who can connect a set of manifold gauges to a unit,...
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1answer
36 views

HVAC Adding a Common

Got a new Honeywell WiFi thermostat and need to add a common. Currently the 3 common wires per the diagram (BL, BK, GY) are wired to one side of the AC Unit. Is there an issue if I piggy back a ...
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1answer
38 views

Second Floor Bedroom Little HVAC

I have one bedroom upstairs 2nd level that virtually gets no air or heat. The other 2 bedrooms have medium force. For the one bedroom in question, checking with your hand, you feel very little and I ...
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1answer
25 views

Can I safely jumper between either G or Y and RC at thermostat panel to troubleshoot AC problem?

I'm trying to troubleshoot a non-functioning AC. The fan does not come on and there is no cool air/condenser does not run. My thermostat is a Braeburn. Three things I'd like to try for ...
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1answer
45 views

Bad Limit Switch?

My Nest thermostat is not working and it says the red wire is not getting power. The gas company man poked around the furnace and thinks it is a bad limit switch. Question: can a bad limit switch stop ...
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2answers
39 views

Multiple boilers, one expansion tank and fill mechanism?

For a building with two boilers serving separate apartments, I'd like to simplify my design by having only one auto-fill and backflow preventer, and only one expansion tank. These are combi boilers ...
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3answers
57k views

How to recharge a window unit air conditioner?

Can I recharge my window unit air conditioner or do I have to send it to a specialist? The AC unit that I have is about 15 years old (nothing lasts forever)... and I happen to have about 20 lbs of ...
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1answer
45 views

Why is my Heat Pump fan not turning in cold weather?

My heat comes on and you can hear the condenser unit come on as well. However the fan is not turning? The outside temp is 30 degrees? Is this normal? Can anyone share some wisdom on this? Thank ...
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1answer
39 views

Furnace with no “C” connection

I have a mobile home furnace. This furnace only has a 4 wire connection terminal, G,W,R,Y. I also have a condensing unit outside with the 24 volt 2 wires coming to the furnace. I know I connect one to ...
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0answers
24 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, ...
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3answers
511 views

How can I hide an HVAC line on the blank face of house with a chimney?

We have an exterior HVAC line running up the center of an exterior wall to a second floor unit. The face in question is the side of a colonial style, and has a two story chimney with a taper at the ...
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1answer
57 views

Does insulating an Air Conditioner from inside (for winter) increase chance of damage?

I have two window air conditioners that I'd like to seal during winter (Friedrichs). I'm considering sealing them from inside (with blankets or foam) as they let in a lot of cold air and noise. ...
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0answers
21 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 ...
0
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1answer
57 views

HVAC one unit Residential system dual zone forced air

Have a Residential system. One unit, dual zone forced air HVAC. 2 thermostats. Is this type of unit designed to run the heat downstairs, while running the AC upstairs at the same time? The house/...
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1answer
21 views

Blue star inverter spilt ac 1.5 tonn

In my spilt ac the big pipe in the outdoor gets freeze when running ac on low temperature but not frezzing when it running in higher temperature. What is the fault if the gas is low in the compressor....
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1answer
37 views

Heating Split level

I'm surprised that I can't find more useful information on this. I have a split level home. Main floor contains living dining and kitchen. 8 stairs up to top level with 3 bedrooms and a bathroom. ...
0
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1answer
37 views

Direct vent boiler exhaust exiting close to brick chimney

The exhaust vent for our Burnham Spirit direct vent boiler currently exits very near the junction box where I recently installed an IR-triggered motion-sensitive floodlight. The hot air is causing ...
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1answer
38 views

Goodman GMNT100-4 Unit- Blower Motor Works for Air But Not the Heat

I have a Goodman GMNT100-4 that air conditioner was working great. However, I recently turned on the heat. The system goes through all sequences fine until it's time for the blower motor to kick on, ...
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1answer
46 views

1999 Goodman furnace modeld GSMS060-3

Furnace goes through the normal start up process but after 5 minutes the flames go out and I hear a click in the induction motor not the main fan. What could I check. I have taken out the flame ...
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2answers
49 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 ...
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1answer
35 views

Why doesn't my HVAC system use the away temperature setting?

I have a Carrier Infinity dual-fuel 5 stage HP w furnace. I set the away temp much lower than the home temp but the HP keeps running to bring the temp up to the next home temp. I would think the ...
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1answer
39 views

Is my control board bad?

I have a Goodman evaporator/gas heating unit that runs the central fan motor constantly after it is powered up a couple of seconds. This happens regardless of what wires are hooked to the control ...
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2answers
35 views

Gas heater fan noise

I have a CF653C-H Cozy wall gas heater ..The fan runs fine , except when it shuts down , it clicks 15 to 20 times before stopping . At least I am guessing its the fan, could also be the motor ..But ...
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1answer
34 views

Converting I+ I- thermostat to 'standard' wiring

I've been replacing my thermostats with the RadioThermostat CT50, which reports to my home-brew home control/alarm system. I have a 3-year old AireEase 4-ton unit in the shop that has a Comfort Sync ...
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2answers
3k views

New condenser fan motor burned out

AC technician replaced my condenser fan (through a home warranty service). The new fan worked for 5 min and stopped working after that. the fan motor was extremely hot (180F or more) The old fan motor ...
3
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1answer
41 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 ...
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1answer
41 views

burners out of sequence with blower motor

I have a Bryant furnace plus 90 model #398AAW036060D. I just changed the blower motor. In the last five years I've changed the main board, inducer board, pressure switch, and cleaned the igniter the ...