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Questions tagged [hvac]

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

3
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0answers
38 views

Why isn't my furnace igniting?

I noticed cold air from my Carrier 58SS furnace. The main burners were not lighting. The pilot flame was strong, but yellow. When I tapped on the gas valve, the pilot shut off. I removed the pilot ...
2
votes
0answers
66 views

Junction Box Blank Cover in HVAC Duct

I am starting a bathroom remodel second story that requires a length of NM wire to be lengthened by a few feet. I realize I can't do this hidden in a wall or floor and need this done in accessible ...
2
votes
0answers
56 views

Mini-split HVAC in new build?

Next few weeks I will be in the process of getting quotes for mini-split HVAC system. Curious, if anyone has gone ductless and if so, how is that working out? The house will be a a two story build(...
2
votes
0answers
55 views

Replacing a motherboard on a Carrier 8000VS Furnace

Hi guys, I am trying to finalize the wiring of my new carrier motherboard. I have about four more wires to connect and the new motherboard is slightly different than the old one. The pictures I’ve ...
2
votes
0answers
1k views

Difference Between Take Off and Starting Collar - Which One Should I Use?

I am in the process of installing a whole house humidifier. I am planning to mount it to the supply side and need to connect the bypass to the return. I'm not sure if I should be using a take-off or ...
2
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0answers
422 views

Installing Ecobee3 with Trane Furance

I am installing an Ecobee3 and have found that, while the common wire exists, it is not connect to the furnace. The wiring schematic for my specific furnace can be found in this PDF There is no ...
2
votes
0answers
5k views

Increasing gas pipe size from 1/2“ to 3/4” at appliance

I'm planning to purchase and install a new condensing tankless water heater (Takagi T-H3J-DV-N) that will supply both domestic hot water and space heating (radiant via heat exchanger, separate closed ...
2
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0answers
1k views

Trane Weathertron Stat to Honeywell RTH2510

I have a Trane Weathertron thermostat thst I am replacing with a New Honeywell RTH2510. This is a heat pump with auxiliary electric heat. The wires on the Tran thermostat are. R, T, O, G, Y, B, X2 ...
2
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0answers
67 views

Air handler for an AC in the attic collect about 1 cm of water in it before it is high enough to drain… problem?

My air handler in my attic won't drain water(because the hole is 1cm above the pan) until the water reaches that hole. Why is this setup this way. From what I have read, NO water should be in the ...
2
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0answers
3k views

Reducing air conditioner compressor vibration noise

I have a two year old Carrier air conditioner with an outdoor condenser. The condenser sits on a plastic pad on the side of my house, and I have two--one for downstairs and one for upstairs. ...
2
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0answers
550 views

How can I insulate and elevate an A/C line set on a flat rubber roof?

The Scenario An apartment building with a flat black rubber roof. The A/C condenser is on a platform on the roof with an air handler inside the unit. The line set runs across the roof for about 20 ...
2
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0answers
855 views

What are good Relative Humidity and Temperature settings on an MHRV and are the settings related?

I need to configure the threshold Relative Humidity and Temperature settings on an whole house MHRV system. The way the system works is that if the RH threshold is exceeded the system increases the ...
1
vote
0answers
27 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....
1
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0answers
23 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 ...
1
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0answers
32 views

AC unit not turning on

My A/C doesn't come on when I set the temperature on the Braeburn thermostat very low. Also, the recirculation fan doesn't come on when I set the thermostats fan setting to 'on', as though the indoor ...
1
vote
0answers
38 views

Is one large whole house fan better than two smaller ones?

I'm having an addition put on my house and I'm considering the "Quiet Cool" line of whole house fans. The fans are quite expensive and price wise two small fans are almost the same price as one ...
1
vote
0answers
46 views

Controlling one FCU with two thermostats

I have a chilled water fan coil unit that will feed two areas, living and the bedroom. I want to control the FCU with two thermostats, one in the living and one in the bedroom, (preferably) in a ...
1
vote
0answers
24 views

U.s. boiler / Burnham boiler alterations

i have a 203ncl-tei2 boiler installed in danvers Massachusetts. Regular elevation. This boiler also has a failed tejurland (universal control) powerventer motor on it that is only humming, not ...
1
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0answers
205 views

Daikin Mini Split Runs Constantly

We had a Daikin ductless system installed as a replacment for our old system that finally died. We have 4 total units inside the house, with 1 in each of the 3 upstairs bedrooms and a larger 18K BTU ...
1
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0answers
46 views

Can I use an available wire as a C-wire by adding it to an unoccupied 24v terminal?

I want to add new thermostats in my home. Luckily, the wiring to my thermostat has an unused wire in the bundle for the required "C-Wire". It has R,G,Y,W, and an unused blue. The thermostat wiring ...
1
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0answers
66 views

Why is there a hole in return duct

There's a hole in return duct going under my house; why?
1
vote
0answers
40 views

HVAC indoor fan stuck buzzing

My old Sanyo SAP-KRV123EHA had a noisy ball bearing in the indoor fan unit. Since Sanyo is no longer making these units I tried replacing the fan bearing with ceramic ones. After assembling the motor, ...
1
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0answers
23 views

Furnace won't light when fan commanded on

House and furnace are 5 years old. Furnace is an Allied A95UH2V090C16S-07 and is interlocked to a Lifebreath HRV. Functioned fine up until a couple days ago. My wife calls me and tells me that ...
1
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0answers
34 views

thermostat does not accept C wire connected to AC unit

I have three identical thermostats, model Radio Thermostat CT101. Two of them have C wires connected to the burner and work fine. The third one controls a heating zone and also central AC. It has R ...
1
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0answers
29 views

CAR duct in same bay as electrical wire

I'm going to install a cold air return (CAR) duct through an interior wall that has some electrical running through it. The CAR duct will run vertically, but near the bottom third of the bay there is ...
1
vote
0answers
14 views

Can I place the MUA vent directly beneath the range?

In California, I'd like to upgrade my range hood and may require make up air. I've seen these installed in the toe kicks of kitchen cabinets. Would it be acceptable to install registers directly ...
1
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0answers
26 views

Heating zone only partially working for gas boiler

I did all of these things: Checked the pressure and temperature, which looked OK Attempted to "purge" the area. The zone (let's call it Zone 2), was purged by opening the valve on the return. I had ...
1
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0answers
43 views

No 24VAC between R and C on Rudd R801 Control Board

I’m replacing a older programmable thermostat with Ecobee 4 which is to control a Ruud R801 HVAC unit installed last year. I have access at the thermostat to a wire (orange) that goes to the C ...
1
vote
0answers
45 views

Honeywell Thermostat to Nest E Dehumidification

I am trying to replace my Honeywell Prestige IAQ thermostats. I noticed that my downstairs thermostat has a dehumidification option (upstairs shows no such option). I checked the wiring at the ...
1
vote
0answers
30 views

Dual energy controller 2AC02700701 runs heat pump with low fan only

I am running a central heat system that uses a heat pump as stage 1 and a gas furnace as stage 2. The thermostat is not directly connected to the furnace and heat pump motor, instead to goes through a ...
1
vote
0answers
263 views

Where should I connect my C wire on Goodman GMP075-3 Rev.B

I am trying to install an ecobee4 to replace a digital battery powered thermostat. I removed the existing thermostat and found that there was a spare blue wire that was wrapped around the others that ...
1
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0answers
389 views

How to wire a Taco zone valve controller with ecobee

I'm having an issue with wiring my Weil McLain gas boiler. It was wired up fine and working for a single zone. I added (2) 4 wire zone valves in. So I now have 2 zones, a Taco zone valve controller(...
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0answers
40 views

unique ? about venting tankless water header

I am installing a tankless water heater at the house. My question is unique because I can not find a reference anywhere in the code and the installation manual about where to place my exhaust vent. I ...
1
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0answers
22 views

Upgrade Rooftop HVAC

I am planning a rooftop HVAC upgrade. My current HVAC frame (leg) has cracked one of the 2 x 6 roof rafters that I have repaired with wood glue and anchor screws, so it is good now, but it served as a ...
1
vote
0answers
57 views

How do I calculate fan size for a single room exhaust system to reach a desired cfm when restricted to specific duct size/route?

I am wanting to exhaust a sealed room (except for air intake and exhaust). The room is 512 ft3, and due to positioning, orientation, and existing construction, I am restricted to using 6" flexible ...
1
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0answers
170 views

Trane xv90 blower won't come on regardless of what the thermostat is set at

I have a trane xv90 and the blower won't come on. I'm getting about 20 green flashing lights and then 1 red which kinda overlaps the 21st green. What does it mean? I had turned on my trane air ...
1
vote
0answers
50 views

What heating mechanism do I have and how do I turn it off?

This is a bit embarrassing but I'm unable to figure out how my house is actually heated. I have some vents in the wall (just above the baseboard), which blow out hot air and are controlled by one ...
1
vote
0answers
78 views

Changing AC Fan Motor/Capacitor with No Luck

Issues with a central AC unit: Turned it on and heard a buzzing sound, but the fan didn't start. Started by looking at the dual capacitor. We happen to have two identical units, so I tried the ...
1
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0answers
2k views

Carrier Infinity System says “System Malfunction”

On this, the day temperatures reached 95, my AC stopped working. Here are the symptoms: The thermostat says "Infinity System - System Malfunction Call Technician". The condenser outside is spinning, ...
1
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0answers
84 views

Correct wiring for Nest thermostat with dual HVAC system

Trying to wire up this new-fangled Nest Thermostat E (the cheapy edition) to my home HVAC system, but unsure of what to do. At the thermostat, I have G, W, Y, R, AND Rc wires, but the R and Rc wires ...
1
vote
0answers
810 views

Furnace Mainboard wiring with AC unit

I went to install a Nest on my upstairs HVAC unit. After installing the Nest I thought it was functioning properly. The next afternoon I came back to the house It was still hot, so looking into this ...
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0answers
326 views

Do I need to install the separate 24 VAC transformer on my Lennox furnace for a new Aprilaire 700 Humdifier

I'm replacing a whole house Aprilaire 760 humidifier with a new 700 model. It appears that everything is the exact same dimension so I'm intending to pull the old one out and simply install the new ...
1
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0answers
907 views

How to understand the red and green blinking lights in Trane gas furnace?

My 8 year old Trane Model tuh2d120a9v5va furnace is not giving out heat, but the blower is on. The service people are all busy due to the recent storms. I imagine the ignition is not working. ...
1
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0answers
820 views

Furnace Condensate freezing on siding

I am helping a client with an issue related to the condensate line on their furnace. It is a high efficiently LP furnace installed in an attic with a condensate line that drains to the exterior. The ...
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vote
0answers
28 views

Switch from 5“ HVAC Air Filter to 4” Air Filter?

Hi: I have 2 HVAC systems that use 20" x 24" x 5" air filters that are quite expensive to replace @ $60 each every 9 months. Would switching to 4" filters be ok assuming I change them slightly more ...
1
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0answers
42 views

furnace wont kick in

My furnace seems to work intermittently. overnight its seems to stop... i have checked the thermostat and it shows says it is heating. fan is on auto, but nothing coming out. when i turn heat to off, ...
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vote
0answers
1k views

Running Airwave/Fan schedule with Nest (With Fresh air intake HVAC)

I am trying to make sure I am understanding the research/studies behind using just the fan to help reduce energy to cool/heat home. Nest has the option to set a schedule to run the fan in home to ...
1
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0answers
2k views

Nest thermostat - electrical buzzing/humming noise

I have recently installed two nest thermostats (the black gen 3, and white model E). The system is gas radiator heat wired to the model E via the usual Rh and W wires, and Rh, Rc, Y, G, W wired to the ...
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0answers
49 views

Heat pump shut down after 15-20 secs in cool mode

I have a York Stellar 2000 series Heat Pump model E1CS add-on system to a gas furnace. The heat pump had been working fine for a great many years. It now has problem in the cooling mode. When the ...
1
vote
0answers
600 views

Putting a window air conditioner into an awning window

I bought a window air conditioner thinking that I could alter my awning window to accommodate it. I have since discovered that I can't remove the part of the window that swings out or alter it so that ...