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

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0
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1answer
38 views

electric heater keeps needing to be reset by turning fan on and off atleast every 1-2 days

My electric furnace is about 23 years old, it quits working but does not trip a breaker. It feels warm to hot at furnace and just kind of clicks occasionaly when I turn thermostat up to 90 to try and ...
2
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1answer
152 views

Can't get my AC to turn on at all

Recently our AC stopped working. The thermostat is working properly, but the unit just started blowing hot air. I've never worked on a AC before, but I was trying to save some money. Anyway started ...
0
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1answer
38 views

AC Condenser Fan Won't Spin and Overheats But Can Be Kickstarted

Symptoms: AC kicks on, but blows warm air Found issues: AC kicks on and AC condenser appears to turn on (makes noise), but the fan won't spin. A few seconds later, the condenser fan motor overheats ...
0
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1answer
89 views

New Thermostat installed but compressor comes on immediately

I have a new Insteon Thermostat that I'm using to replace my prior Honeywell t-stat. This is installed to a relatively new HVAC system (both AC and Heat) that DOES have a "c" wire. I've attached the ...
0
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1answer
38 views

Oil furnace fan won't shut off when “heat” plug is connected to control board

I was changing my thermostat and I attempted to make the swap live without turning power off. When I connected new thermostat, the fan kept running. Ruled out bad thermostat and wire short by ...
0
votes
1answer
1k views

What could be causing my Lennox furnace to blow cool air?

My Lennox outside furnace is blowing cool air, not hot even when the burner is lit. It takes 3 times longer to heat the house than it should. I just had the draft motor replace about a month ago and ...
0
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2answers
88 views

Furnace fan works properly intermittently

My furnace fan sometimes stays on and runs continuously. I can stop it by flipping the breaker for the furnace on and off. It then stays off. When heat is called for, the fan comes on again and ...
1
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2answers
319 views

Gap between 6“ dia wall thimble & 6” hvac pipe

I bought a 6" dia aluminum wall thimble to vent my 6" dia hvac steel exhaust pipe through to the outside. However, the diameter of the 6" thimble is actually 6 3/4". How do I effectively insulate the ...
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1answer
22 views

I have an electric furnace that sometimes blows cold air

I have an electric furnace that blow cold air sometimes. I replaced the thermostat and that did not fix it. The fan blows fine. If I shut if off for a few minutes and then try again, about half the ...
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2answers
157 views

Issues after capacitor replaced on AC unit

Had a checkup on my AC/ furnace a couple weeks ago. The technician said the capacitor leaking oil and not pulling enough amps. He recommended me getting a whole new system. (My house was built 6 yrs ...
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5answers
78k views

Why won't my A/C turn on after I replaced the thermostat batteries?

Our thermostat died yesterday, but after replacing the dead batteries with fresh batteries, and confirming the LCD screen was operable, our AC no longer turns on. I have attempted a factory reset on ...
3
votes
1answer
46 views

What inspections/maintenance should be done before first air conditioning of summer?

I'm a typically handy guy who knows his limits. I recently moved into a new house so am unfamiliar with the history of the equipment. Before I switch the thermostat to A/C for the first time this ...
5
votes
4answers
21k views

Can I using a 3-phase connection to power 1-phase AC unit?

I have preparation for an AC connection with 3-phase 220V 3X16A breaker. I want to install a 220V 1-phase unit, which also needs a 16A breaker. The physical connection has screw-on terminals, so there ...
1
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0answers
17 views

Clean filters and dusty house

I have good airflow and a very dusty house and large dust balls. I have used all kinds of filters including the pleated. When filters are checked in 3-6 months they are as clean as the day they were ...
1
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0answers
40 views

AC capacitor testing with multimeter

When running through my check list to start the AC for the spring/summer I noticed the outdoor fan was not running, hence no cooling. I'm using a basic digital multimeter to test a capacitor with the ...
1
vote
1answer
70 views

How to power Honeywell wifi thermostat with external transformer

I want to install A Honeywell RTH 6580 WF thermostat in my garage for heat only . My heater is a simple LP gas, hanging unit heater; heat only and my thermostat has two wires labeled W and R . I ...
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0answers
33 views

Theremostat indicates low battery even with new cells

I have a 3 story home with 3 different thermostats, one on each level. The first floor one says "lo batt", so I changed the batteries. That thermostat still reads "lo batt" and my system will not turn ...
1
vote
1answer
39 views

Limit switch doesn't function on oil furnace

my limit switch on my oil furnace does not shut off the burner when it hits the limit.I replaced the limit twice maybe I had a bad one still no luck . While furnace was running I took the thermostat ...
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2answers
263 views

Trane xv80 3 blinks

Trying to be as thorough and concise as I can, zero experience with hvac. I have a year 2002 Trane xv80 that is giving me the three blink code, which indicates a pressure switch issue. I ...
1
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0answers
42 views

Thermostat will not power on with C wire, but it has voltage

I recently purchased a Honeywell wifi thermostat and tried to hook it up as a replacement for an existing battery powered unit. I have a typical forced air HVAC setup with gas furnace (no heat pump), ...
1
vote
1answer
25 views

Why might a thermostat refuse to switch from Heat mode to Cool mode?

I have this Honeywell RTHL2410C programmable thermostat and typical Florida electric AC system. Starting this Spring, it has started behaving strangely when switching from Heat to Cool mode. The ...
1
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3answers
52 views

Duct sizing impact on flow

We have a ranch with a wood fireplace in the living room. It's fantastic at heating the main living area, but the bedrooms down the hall get left in the cold. I'm going to install insulated flexible ...
1
vote
1answer
464 views

Why does the blower in the attic vibrate during heating when it is really cold?

We have a Carrier heat pump system in our home, and the blower is located in the attic. When it is especially cold, the blower runs on high (there are three levels: high, medium, low). During this ...
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0answers
14 views

Comfortmaker Run Capacitor Location?

Where is the blower run capacitor likely to be physically located within a Comfortmaker central HVAC unit? Access is tight in the attic space. Thanks!
2
votes
2answers
10k views

How should I evaluate my central A/C to see if it's working properly?

I was once told by a service tech that they evaluate how well the system is performing based on temperature difference between the the return and supply sides. On our first really warm day (80F+), I ...
1
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1answer
4k views

How do I connect my whole house humidifier to my furnace?

Connecting Desert spring Humidifier to the furnace: Do I eliminate the 24V transformer that came with it? The furnace Keeprite has the the electronic board says Humidifier W1 and C. where can I ...
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3answers
26 views

Mount horizontal 6" metal exhaust pipe to wall economically?

I'm trying to add more ventilation to the back room of my garage. The only available outside air exit location is 25' horizontally along the front room of the garage's wall. I have 6" 30ga sheet ...
3
votes
6answers
41k views

What could be causing an A/C blower motor to turn off randomly?

The Blower motor on my AC unit turns off at random times while the outside unit continues to run which is causing the coil to freeze up. The blower won't come on for 30-45 minutes after the AC has ...
4
votes
4answers
15k views

How can I connect two indoor ductless A/C's to one compressor?

I have one Hitachi i-clean split AC 2ton unit installed in my home. I want to connect another indoor ductless unit to the already installed outdoor compressor. I only need to use one indoor unit at a ...
1
vote
1answer
214 views

Why would only 1/3 of my registers be blowing warm air?

I have a Coleman gas furnace in a wall space in my house which somehow shares the blower on my a/c unit on the roof because it turns on when furnace is called to start, though it does bump up after a ...
0
votes
1answer
42 views

Could a leaking boiler be fixed?

I'm having a leaking hole in the cast iron boiler tube so does it mean that its time for a new boiler or is there any way it could be permanently fixed?
1
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3answers
62 views

What's the most cost effective way of ventilation automation given no prior knowledge in the field

I have 3 fans for air inflow, and 3 fans for extract, all in one big hall. Currently I set the power of their motors with dimmers myself, looking at CO2 and temperature readings. I want to replace ...
1
vote
1answer
110 views

How to connect thermostat to newly-installed condenser/evaporator unit

I installed a furnace evaporator and condenser brand goodman 4 ton unit but need to know how to connect thermostat from condenser to the furnace to the thermostat if any suggestion.
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0answers
24 views

5 year old Air handler fan not rotating or slow

5 year old Heil AC unit not cooling. It appears the air handler in the attic has a fan that is not turning when I turn on cooling from the stat. If I turn on the fan from the stat it turns but ...
1
vote
1answer
118 views

How to Change Chinese HVAC Thermostat

I am looking to put Nest thermostats in the house, I have now found out my entire house (one in each room, 6 of them) has been wired with HVAC Chinese U12A UNIVERSAL A/C CONTROL SYSTEM urrgh – they ...
1
vote
1answer
34 views

What could be causing my Thermostat “R” wire to only be 8 VAC?

I am trying to install a Nest thermostat. It says Rh not powered. I checked with a meter and I get approx 8 VAC reading. What could be causing this? The furnace itself ain't pretty. Update: ...
0
votes
1answer
229 views

Central AC is Icing up, but not cooling my house

My central air conditioner isn't cooling like it used to. I noticed that the refrigerant lines entering the evaporator coil in the plenum were icing up. What might the problem be?
0
votes
0answers
11 views

Replacing Flex Duct

I have few questions and need some advices. 1. can you tell me the size of my unit. It is Bryant, model 561CJX018000AEAA 2. The furnace is in crawl space and connects with 12" flex duct, 40 feet long, ...
1
vote
1answer
35 views

Replace insulation in a Trane HVAC? (TWE030C140B0)

I found a little mold on the foil covering the insulation in my TWE030C140B0 air handler/ AC/Heater. I am 95% sure I have the moisture problem resolved and now I need to replace the insulation. Does ...
0
votes
2answers
48 views

How do RH/RC/R and Y/W relate for HVAC?

I have the following notes for HVAC (that I've compiled from reading through here): Thermostat wiring: C low voltage power wire that brings power from heating/cooling equipment to thermostat ...
0
votes
1answer
45 views

Does it take long time to turn AC unit around?

I am wondering if it can take a full day of work to turn around AC unit like in this post . Must my new air conditioning unit be 3 feet from the wall (or positioned backward)?
1
vote
1answer
86 views

Must my new air conditioning unit be 3 feet from the wall (or positioned backward)?

My contractor installed this system yesterday, at my property: "Trane T4TTR6060C1000A RX16 5 TON XR16 A/C 16 SEER rating R410A". Everything is working fine. I just do not like aesthetically how he ...
1
vote
1answer
24 views

Does the air temperature outside at the time of spring inspection matter when the tech comes to inspect and clean the inside and outside units?

I have semi annual inspections done on my A/C units both inside and outside. Will the temperature outside effect the tech's ability to properly clean and evaluate the operation of the units? The ...
0
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2answers
29 views

can I use AC top cover for Trane XR16

My contractor installed this system yesterday, at my property: "Trane T4TTR6060C1000A RX16 5 TON XR16 A/C 16 SEER rating R410A". ...
1
vote
3answers
60 views

How is the Air Conditioning wiring supposed to connect to my furnace?

My dog has chewed through my wires on my unit that turn on my fan at the ac unit. This is not the first time. Its always been an easy fix until now. He actuall pulled the wire from the unit and I ...
3
votes
1answer
90 views

Mounting a window air conditioner on top of a sliding horizontal window

I need to install a window air conditioner in my master bedroom. However, the only suitable window there is a horizontal sliding window. To complicate things more, I need to place it on top, since my ...
0
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2answers
52 views

reclaiming exhaust from 'on demand water heater'

Is there some way to recover the heat which is lost through the exhaust system from a 'on demand water heater' ?
1
vote
1answer
28 views

What is 3" (750Pa) wg class?

According to Sheet Metal & Air Conditioning Contractors’ National Association (SMACNA) - leakage test manual, It is not recommended that duct system constructed to 3" (750Pa) wg class or lower be ...
0
votes
0answers
8 views

Need to clean permanent air filter

How do I access the permanent filter in a RUUD product ? The model number is either UBEA-14JO5SFFAI or RCGA-24A2GG14?
1
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3answers
53 views

Compressor/fan stays off when cooling turned on

Before I begin, I would like to request "call a technician" suggestions to stay off. I do know a nice guy who can look it up for me, for a variety or reasons, one of which being my general history of ...