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

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2answers
66 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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0answers
28 views

Where can I find a user manual for the Honeywell 32207455 thermostat?

How can I obtain a manual for the subject thermostat? There seems to be no manual on the internet. We are trying to adjust the system and run into several questions.
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0answers
37 views

time delay adjustment on Rheem elect furnace

Upon a call for heat the blower motor starts too soon resulting in cool to cold air coming out of the ceiling registers until heat strips start heating up.Wires coming from thermostat connect to ...
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0answers
36 views

goodman furnance just keeps runing no heat why

recently i have had problem with my goodman furnance all it seems to do is blow air on very low speed and does not seem to stop furnance just keeps running i replaced limit switch work fine but after ...
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1answer
68 views

How to wire programmable thermostat that doesn't have an E termimal

I am trying to replace a manual with programmable thermostat that is missing emergency heat (E) terminal. There are bits and pieces of information I have gathered but am still not clear. Can I leave ...
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2answers
64 views

How to HVAC service 3 floors without ducts in roof?

This is a little simplified, but not too much. I have architects and plans for a a two story house plus a basement. The house is about 80 feet by 20 feet with all stories extending the whole ...
3
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1answer
211 views

New Thermostat Ecobee3 to Old Galaxy GG-75 boiler - Needs common wire

I would like to replace my old thermostat with a new Ecobee3 thermostat. HVAC system is a Slantfin Galaxy GG75 boiler - single zone. (No air conditioner.) Current set-up has only a red and white ...
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0answers
60 views

HVAC - hot air flowing on both zones when only 1 zone should be on

I have 2-zone forced air heating, with separate thermostats for each zone. Normally, if the thermostat in zone 1 triggers the system to go on, the heat will only blow through the vents in zone 1. ...
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0answers
49 views

Could my New Hot Water Tank be improving my Furnace

I've gone thru 2 blower motors in my furnace in 3 yrs. Techs don't know why. I purchased a New Water Tank recently and it seems strange but my furnace is working better. Usually I could hear noises ...
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2answers
109 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 ...
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0answers
19 views

Can I use the unused brown wiring for my old thermostat for Nest Thermostat’s advantage? [duplicate]

Here are the images I figured out all the other connections as W/W1, Y/Y2, G, R & C but the brown wire is not connected to anything. What could that be for? Edit: From this answer I figured it ...
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1answer
58 views

wi-fi thermostat wiring for Carrier FE4 elec. furnace w/heat pump

what is the correct wiring diagram for a honeywell wi-fi thermostat on a carrier FE4 elec. furnace w/heat pump
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1answer
45 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 ...
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1answer
133 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 ...
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2answers
157 views

How to seal HVAC ducts running through old window to addition?

My house has a small addition that was added by the previous owners. They ran the HVAC ducts through an old window and some of the block: The rectangular section in the window should be easy ...
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4answers
2k views

HVAC supply vent noise: how to eliminate the whistling wind tunnel?

Every time the heat turns on (rented house), we are getting choked with too much dry hot air in our small room. When I try to close the supply vent it produces a really loud whistling noise. I either ...
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1answer
108 views

Trane furnace pilot wont stay lit

I have a 1983 Trane gas furnace, Model BLU108E936B1, the pilot light went out, I could get it to relight but wont stay on> Changed the thermocouple, same results, Pilot light doesn't look right as I ...
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2answers
67 views

Aprilaire 700 humidifier not working properly

The fan does not seem to be running. How can I determine what the problem is? I'm not sure if it's the fan, solenoid or the computer board.
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1answer
65 views

Actual efficiency of an old oil furnace?

We purchased a house with what appeared to be a relatively well-maintained oil furnace, about 30 years old (installed in 1984). We don't have any records of annual oil usage, or any way to find that ...
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0answers
24 views

coleman furnace model dgaa furnace heats up and shuts down berfore blower starts and flashes code 4

york DGAA will work fine until it gets close to hot enough for the blower to turn on. I said close to turning on because I think it should get hotter but I'm not sure just guessing. The upper limit ...
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1answer
183 views

Air Conditioning Drain Pump

I am going to purchase Multi-Split air conditioning unit for my apartment that I am fully renovating at the moment. So it is the right time to make wholes in the walls etc. The supplier is giving an ...
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0answers
49 views

Mini Split condensate pump to condensate drain

I'm working out the details of my Mini split. I know by code I have to have it connected to a 3/4" condensate line going outside. The Mini Split's air handler is located on an inside room where I'm ...
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2answers
297 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 ...
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3answers
145 views

Heat Pump - emergency electric strips - how controlled?

I have a recently installed combination of a Goodman electric package unit, and an ecobee smart thermostat. This morning with the outdoor temp at 36, I was surprised when I peered out the window and ...
0
votes
1answer
55 views

Water coming down PVC pipe from ceiling to furnace

Water comes down the PVC vent pipe to my furnace and leaks out at the elbow. Water seems to come even when the furnance is turned off. I had a furnance man come out. He said there is a leak at the ...
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1answer
81 views

Emergency Heat Coils vs Space Heaters

I have two heat pumps, in an all electric house. Unfortunately they both seemed to have stopped working at nearly exactly the same time. I have called for qualified repairman, but they won't be out to ...
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1answer
80 views

Insulating ducts in unfinished basement?

Hi I am looking to insulate circular metal air ducts in my basement because the air reaching some of the farther rooms (from furnace) on the second floor of my home is comparatively much cooler. I ...
0
votes
1answer
131 views

What is the rated power of American central air-conditioning control circuit?

I want to know what is the rated power that American central air-conditioning 24V control circuit can supply, which is also the power supply for Nest. Nest gets its power from the 24V control ...
1
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1answer
44 views

Access 2nd-story burst hydronic pipe through ceiling or floor?

We had a freeze which caused one or more bursts in our hydronic heating system pipes. We know that there is one burst in a radiator, but there may be others, according to the contractors. If there is ...
2
votes
1answer
44 views

0v at DC thermostat terminal in furnace

I have an old (mid 80s) Rheem gas furnace I hope will last me through at least one more California winter. It's been known to go down into the upper fifties, so it has its work cut out for it. In any ...
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1answer
64 views

Furnace Fuse Blows Immediately

This afternoon, our Ruud furnace suddenly stopped working. After poking around a bit, I realized that the 3A fuse on the control board had blown. I ran to the hardware store and replaced it, but no ...
0
votes
1answer
30 views

Central air winterization and insulation

Do I need to insulate the skinny copper line on the outside to keep it from freezing and bursting during the cold winter months? Anything else I need to do winterize the a.c. unit?
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0answers
238 views

No C wire terminal on my electric plenum but there is on my furnace. How do I solve?

I had a brand new furnace installed recently but also now picked up a wifi thermostat. The problem I now encountered while installing the thermostat is that my system also has an electric plenum as ...
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2answers
196 views

Rain water leaking around attic furnace

I bought a house a few months ago and when I bought it I noticed what appeared to be a water spot on the ceiling of the top floor. Of course I didn't do anything about it until heavy rains over the ...
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2answers
49 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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1answer
749 views

Correct Wiring for Furnace Blower Motor

After getting my furnace blower motor replaced, it now runs only in the following scenarios: 1. Mode "Cool" Fan "Auto" 2. Mode "Cool" Fan "On" 3. Mode "Heat" Fan "On" In other words it will not run ...
3
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2answers
2k views

Hvac Fan only blows in 'fan on' mode while heating

Our HVAC Fan only blows in 'fan on' mode while heating. In other words the fan will not blow in heat mode if switched to "fan auto". Both fan on and fan auto modes work when cooling. See image below, ...
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0answers
33 views

Temporary Remove Flex Duct

I am about to replace a load bearing wall in unfinished basement. There is flexible duct attached to plenum that I need to temporarily move out in order to put the beams in. Do i just need to cut ...
1
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1answer
186 views

Why isn't my Lennox G26Q3/4-100-6 furnace firing up?

I replaced the batteries, does not click when it calls for heat in the thermostat. fan blows but no heat. I took off inspection door, held the safety switch in, a blue light is blinking constantly, ...
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1answer
116 views

Hvac fan runs and shuts off in a cycle when in heat mode

I have a Heil hvac model. N44336336GKE100, The system works ok when in cool mode but when in heat mode the outside fan runs for 30 sec then shuts off for 20 sec and continually repeats the cycle. I ...
2
votes
1answer
267 views

What is the optimal duty cycle for a furnace?

A heat load calculation of my home says it requires ~36K BTU/hr of heat at a normal winter temperature (40°F), and ~52K BTU/hr at the design temperature (24°F). An HVAC contractor has proposed ...
1
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1answer
80 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 ...
2
votes
1answer
40 views

If water level is rising on its own on oil heating unit instead of going down, could I have a leak? Or something worse?

If water level is rising instead of lowering on oil heater unit, is there a leak? Could something worse happen. Oil man had to drain water to lower water, and said to watch it to make sure it doesn't ...
1
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1answer
60 views

How do I compare furnace models?

I need a new furnace, and I have quotes from two companies, for three different brands of furnace, Carrier, Trane, and Lennox. Both companies have provided the model numbers of the units they would ...
1
vote
1answer
108 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 ...
1
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0answers
25 views

Is there a “bending rigidity index” of some sort for semi-rigid aluminum ducts?

Some semi-rigid aluminum ducts bend easily and others do not. I want to purchase semi-rigid aluminum ducts online of a specific bending rigidity/stiffness that minimizes sagging but can be easily ...
0
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0answers
145 views

What makes a furnace pilot valve whistle?

I have a furnace that started whistling, recently. I have read that gas pressure changes can cause this. Others have remarked how seasonal gas changes can lead to a properly-adjusted furnace to ...
0
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0answers
18 views

Installing a Wifi Honeywell Thermostat with a C wire [duplicate]

can someone please help me out here. I'm installing a Honeywell Wi-Fi Thermostat and this Thermostat requires a "C" Wire. Can someone please tell me by looking at the pictures attached if I have a "C" ...
0
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1answer
55 views

Does cold galvanizing compound restore the rust protection of a galvanized duct?

The house is a ranch built on slab on grade with a newer furnace in a downflow configuration with A/C. The in-floor clay tile supply lines are in good shape and clean. The original 60 year old in-...
2
votes
2answers
920 views

Wifi Thermostat to Reznor Garage Heater. No “C” wire connection on terminal strip

I just had a 75000 btu Reznor UDAP garage heater installed. Can I run a "C" wire for a smart thermostat if I don't have a C connection on the terminal strip? There is a C connection on the circuit ...