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

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30 views

Heat Pump Extended Distance from House

I am replacing a Gas Pack with a Dual Fuel Heat Pump. I live in Tennessee so the temperatures are generally moderate. The location of the current pad is right next to the house, between my deck and ...
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2answers
192 views

How to address loud cold air return

The cold air return on my forced air furnace is too loud. While it is is tolerable, there is a noticeable sound of rushing air when the furnace is running (not a whistling sound, just a blowing sound)....
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2answers
112 views

HVAC technician can't do ductwork because of zoning limitations?

I'm doing a renovation on an unfinished area, size about 350 sqft. During my rough framing/electrical/mechanical phase inspection, my county inspector didn't mind the idea of tapping into the ...
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1answer
33 views

Why doesn't the extra C wire work when hooking up WiFi thermostat?

My existing thermostat has an extra 5th wire. It's blue. We used that as the C wire. We have forced hot air so we checked the furnace and it has all the wires hooked into a clip that plugs in. It has ...
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3answers
332 views

How to insulate register boot?

The county inspector dinged me on a couple of things for my bonus room renovation. One of these things is wrapping the register boots (endpoints) in insulation. I've seen registers with this ...
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1answer
30 views

how to measure CFM in digital animometer [closed]

dear friends how to measure CFM in digital anemometer and tell how its calculated in both practical and theoretical
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3answers
4k views

Installing Honeywell WiFi Thermostat

I am trying to upgrade to a programmable thermostat. I bought the Honeywell RTH9580 with WiFi. I can get power to the new thermostat and get the fan running. However, it will not work when the fan ...
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1answer
78 views

Home Air Conditioner Problem

I have an air conditioning unit that was here when I bought the house. It was in the 70's here today, but I have an old house and windows don't open so the house was hot. I decided to turn on the ac ...
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2answers
64 views

Why is my booster fan pulling cold air from outside?

This is my first winter in a house with an oil-heated, forced air system. I noticed my wall vents were pushing out warm air, but the floor cold air return vents were pushing out cool air. I followed ...
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2answers
1k views

Should I bypass a thermal cut-off switch on my oil furnace?

My thermal cut-off switch for my oil furnace blew and my neighbor replaced it until a tech could come out and check it when I had my cleaning. The switch blew again and the furnace tech bypassed the ...
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3answers
92 views

Furnace turns off power to the thermostat

When my natural gas furnace is running for a while and it gets too hot, the limit switch turns off the burner. When it does this, the power also gets cut to my thermostat. This causes the thermostat ...
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5answers
268k views

How can I add a “C” wire to my thermostat?

So, the spiffy new wi-fi thermostats want power on the C wire from thermostat, but the old thermostat doesn't have a C wire at it. What's the easiest way to add the C wire/24 volt to the thermostat ...
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1answer
39 views

Why does my nat gas furnace pilot light stay lit at normat temp setting, but goes out when I bump the temp up a couple degrees?

Recently the gas company replaced our meter and thermocouple. After they left, the pilot light kept going out randomly. 4 techs came over a 3 day period and could not diagnose except to reassure ...
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2answers
74 views

Bedroom 10 degrees colder than rest of floor!

I'm at my wits end. I just moved into a new (for me) 2 story house (1998) that has some weird heating issues. The house is about 3200 sqft the upstairs is heated by a furnace located in the attic. its ...
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2answers
42 views

Is there a way to measure the output of a single HVAC vent?

As inspired by this previous question, is there a method or device used to measure the output of a single HVAC vent or the output of a single room? I'm imagining some sort of hood device that could ...
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0answers
22 views

Furnace pilot goes out after furnace runs

I have a Cozy standup wall unit furnace CF553D-H. When the thermostat calls for heat it starts and will power up the ought both fan levels ... Then as it reaches temp and starts the cool down, the ...
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4answers
90 views

Furnace Tries 2 or 3 times before staying on until reaching set temperature

I have noticed my furnace will cut the exhaust fan before lighting or sometimes start heating for a few minutes then stop. A few minutes later it tries again and will stay on until reaching the ...
4
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3answers
40k views

How can I prevent my house from smelling of smoke after having a fire in my fireplace?

We have a wood-burning fireplace in our family room. Fifteen feet from the fireplace is a large cold air return. When the fireplace is stoked, nice and cozy, everything is fantastic. When I shut it ...
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10answers
41k views

How can I prevent my HVAC condensate drain line from freezing?

Last night, my heat (forced air) suddenly stopped. Today, a plumber figured out that my heater is 90% efficient, produces lots of condensate, and the drain line had frozen. We went outside and saw ...
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2answers
20k views

Controlling separate heat and AC devices from a single thermostat

I have hydronic radiator heat powered by a gas furnace situated in one mechanical room of my house and a currently being installed central AC whose air handler is situated in another mechanical room (...
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2answers
324 views

Can I connect the R and C wires directly to the HVAC transformer?

I have a Rheem furnace and a Ecobee3 smart thermostat. I'm having a problem where the Ecobee3 randomly loses power and reboots. I've traced this back to the control board (IFC) inside the HVAC unit. I ...
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1answer
5k views

replace old furnace blower motor with a new one but the wires are different

It is an old Rheem RGAA-100C furnace, On the old motor the wires was: White, Brown, Red, Black and Blue. On the new Motor it has Brown, Brown/White, Black, Red, White, and Blue. I don't know how to ...
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1answer
685 views

Can I remove my vent covers without disconnecting the duct?

I have an old house with flexible duct work in the ceiling. There is mold in at least one. Can I remove the vent covers to clean or will that disconnect the duct work in the attic from the vent cover/...
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4answers
1k views

I need a multiple-switch light switch which can't all be turned off at once

I have a 4 switch (I think it's called "4-gang"?) light switch on the wall. It's not connecting to lights though, but to AC vent doors. Now, these AC vents must never all be closed at once. Meaning, ...
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0answers
18 views

Lenox home AC unit doesn't turn on at all, I need help

If you try to turn the out side unit from out it will turn on , but from inside it doesn't do anything. I check the fuse in the inside unit is good, check the overflow it looks good. I just can't ...
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1answer
370 views

Can't find the circuit board of my HVAC system

I'm trying to install a wireless thermostat for my church building's HVAC system. Currently there is no C wire, so I tried to see where the circuit board was so I could install one. I couldn't find ...
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6answers
2k views

Air Conditioner Can't Keep up

We just rented a condo and our A/C cannot keep up so it will run almost constantly. It can't even keep the temperature constant, it will creep up into the 80s even while running. I measured the ...
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2answers
103 views

Optimizing heating in a heat-pump + electric resistive system

Outside, I have a LENNOX 13hpx-036-230-17 compressor: Inside, the air handler is a LENNOX CBX25UH-036-230-1: The air handler lists 36,000 BTUH cooling capacity, with r410a at 450psi, cust part #...
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2answers
48 views

Air handler unit stops running. Starts when motor touched with metal

How is it going? I just moved into a place I bought. It has separate AC units for both floors. We started having an issue with one of the air handler units. One night when turning the air on the ...
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3answers
97 views

What steps are needed before brazing attic a/c copper tubing with a leak?

Yesterday I discovered water stains on one of the air ducts in my house. I went up the attic and saw that a copper pipe cool to the touch which seems to be linked to the condenser? had a pin point ...
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1answer
17 views

Goodman furnance Air pressure switch - faulty?

I have at least a 10 year old Goodman gas Furnance. The past couple of days the burner and blower did not come on. I do not see any indicator lights come on. The inducer comes on, but nothing else. ...
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0answers
56 views

calculating the size for an a/c compressor

I have been looking around and can't seem to find this anywhere. I am trying to figure out how to size an a/c compressor to an a/c system. Unfortunately I have not sized out the system, so there isn't ...
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5answers
163 views

How to Lower the Ouptut of Oversized Furnace

Questions I would like to lower the output capacity of my furnace if possible. How can I do this? Is it worth doing, or should I just live with it? Is there an easy way? Some ideas: replace burner ...
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1answer
129 views

Carrier Furnace blowing fusible link

My 27 year old Carrier Super Saver furnace fan blower stays running even when the thermostat is off. After some troubleshooting, found out that fusible link connected to what looks like a limit switch ...
2
votes
2answers
63 views

Cost of adjusting the thermostat

Is it more cost effective to (1) play with the thermostat by lowering it at times that you're not home or needing the heat and raising it back later or (2) leaving the temperature on a set amount and ...
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vote
1answer
37 views

Wintertime and AC line frosted & dripping water in basement?

One line IS insulated in the exposed basement ceiling, so I am supposing this frosted & dripping line is the smaller return line? Have a dehumidifier running but the problem remains. What can I do ...
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0answers
36 views

What could be causing my goodman furnance to not work?

My furnace starts, than the blower motor runs constantly, but trips out on roll out limit switch. The air inlet and outlet lines appear to be unobstructed, but when it shuts down there seems to be ...
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0answers
59 views

Liquid line freeze up

Why would the liquid line on residential air conditioner freeze up during winter months, even though compressor isn't running? Have shut breaker off to assure outdoor unit isn't coming on.
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2answers
37 views

Gas Pilots going out

I have a unique problem with the gas pilots in my house. They all seem to be going out. One day I found both pilots in my fireplaces out. Didn't think much of it. I then found the pilot on my hot ...
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2answers
237 views

How does fresh air get inside a house with central heating other than through cracks of door or window on a cold winter day

I'm not sure how fresh air, or oxygen, gets inside my house other than through cracks of window or door on a cold winter day when the central heating system is on. I have a pipe that is coming from ...
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2answers
80 views

What is wrong with my air conditioner

I have been using my air conditioner on and off all summer. The weather hasn't been really that bad this year. But now that the weather is reaching high 80s, my air conditioner decides to die on me. ...
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3answers
511 views

Transfer Grille Baffle

I just finished building a new home and as part of the Energy Star rating transfer grilles were installed above each of the bedroom doors to allow air exchange when the doors are closed. The problem ...
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2answers
562 views

Connecting condensate pump to sewer

My AC condensate pump currently pumps through a vinyl tube directly outside my house. However, I just replaced my broken home humidifier and realized that the previous one never had its drain properly ...
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1answer
24 views

Is ice on ERV door normal?

My ERV is forming ice and condensation on the top of the door and on top of the unit (presumably because the fresh air intake is on that side). The outside tempersture hit about 1 degree F today. ...
3
votes
3answers
9k views

What could cause a flame sensor to stop working so frequently?

Over a year ago after a month in our new house, we came back one evening to a cold home and after some googling, I found out that the flame sensor was dirty and the furnace was starting the flame and ...
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3answers
8k views

Does a whole house humidifier go on the intake or outlet of the furnace?

On what side of the furnace do I install the tank of the humidifier (the warm side or the return air side)?
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0answers
39 views

How to remove ice buildup from window air conditioner

My fan froze on my AC unit in my bedroom window. I was able to move the inside one when it froze, but this one is on the outside. Should I spray hot water on it to get it to move? I was going to use a ...
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1answer
52 views

Pilot lights, but main burners don't on furnace with no flame sensor

I have a Rheem furnace in my house. It recently stopped working. It is the type where the pilot is not always on. Anyways, the ignition will kick in, and the pilot lights just fine. However, the ...
4
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5answers
18k views

Why would my Goodman gas furnace start but not stay on for more than 2-3 minutes?

I've got a problem with my 15 year old Goodman furnace. It starts w/o problem, inductor begins working, hot surface ignitor lights up and ignites the gas. Then the main blower starts working and the ...
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1answer
39 views

Do all HVAC units have a drain line?

I have a rental unit and I can not find a condensation drain line on the home heating unit. The unit is old and my question is do all heating units have a condensation drain? Thank you