Questions tagged [hvac]

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

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1answer
108 views

Which terminal should I connect it to for a “C” wire on an american standard AM4A0A30

I'm trying to connect a 3rd gen Nest thermostat. I have a 2 zoned heat and 1 zone AC. The zone with this thermostat has a boiler wired Rw, W1 and HVAC wired Rc, G, Y1. It's summer so I'm only using ...
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1answer
51 views

Custom HVAC control

I currently have a Nest controlling my LP furnace. I'm getting an evaporative cooler installed and I'd like to also control it with my Nest. This post gave me a good starting point, but I'd like to ...
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1answer
25 views

3-zone HVAC (HZ432) one zone's a/c stops working when hot in afternoon

I have a 3-zone HVAC. All 3 zones a/c worked fine until recently. Now, in the morning, before it gets too hot, all zones still work fine. But in the afternoon, when it gets hot, the a/c to zone 2 ...
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2answers
83 views

Thermostat White-Rodgers 1F82-261 switches to stage 2 heat for no apparent reason

I am running a central heat system that uses a heat pump as stage 1 and a gas furnace as stage 2. The thermostat used is the White-Rodgers 1F82-261 which supports 2 stages of heat. When using regular ...
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1answer
35 views

How thoroughly should HVAC evaporator be sealed?

I noticed that cold air was rushing out of the seam near my AC evaporator, so I added foil tape around the seam (see photo). Is that appropriate, or does that minor leakage serve a purpose? The rest ...
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1answer
54 views

How do I remove these ceiling diffuser flaps?

I need to move this diffuser away from the wall and can't figure out how to take out the flaps that are installed. They don't have any screws on the inside that I can see. Is there a trick to ...
1
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1answer
41 views

Running AC/Heater when washing a cleanable filter

I have a heat pump/AC system with a washable air filter. I was told to clean the filter out and run water through it once a month. He told me to let the filter dry for 3 hours before replacing it. I ...
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1answer
61 views

Connecting Common Wire to Control Board

I have a heat pump and want to add a thermostat that requires a common wire. I have read through many threads that show how to add a wire but I already have a few extra in the bundle so its not so ...
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1answer
44 views

Is the PY4G HVAC unit compatible with Nest Thermostat?

I recently bought a Nest Thermostat and I've had nothing but trouble with it. The main symptom is the fan and the AC compressor won't run at the same time. Power only comes through the green wire, not ...
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2answers
54 views

Installing Nest Thermostat. C Wire not hooked up inside furnace

Good morning. I am looking to hook up a Nest 3rd Gen thermostat that I purchased. I noticed I had a C wire upon pulling the old thermostat. Problem is it is not connected inside of the furnace. I have ...
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2answers
246 views

AC contactor 1 pole or 2?

I wanted to title this: Outside unit running, but thermostat is off but I'm 99% sure its the contactor unless someone here says otherwise. Thus my real question: which contactor should I buy? I typed ...
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0answers
29 views

Using existing hot water vent for extraction

I have a room in the basement with equipment (computers) that gets really hot. There is an ac vent but the thermostat is nowhere near the room. Also in an alcove is the hot water heater behind a ...
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2answers
30k views

Why are almost all of my house's HVAC floor registers placed near exterior windows?

My current house is a single story built over a crawlspace and all the HVAC registers are in the floor. In all of the larger rooms, at least one (and usually more) register was placed near an exterior ...
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1answer
18 views

AC red wire placement on control board?

So a fuse(3) on my control board blew at the same time my ac capacitor did. I replaced the capacitor with the exact one that was on the old unit and when replacing the fuse noticed a stray red wire... ...
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1answer
16 views

Adapter for NTC boiler probe

I just bought a replacement NTC probe for my boiler (bought with specific part number) but once the item arrived I noticed the connector wasn't matching. I think this is due to past maintenance when ...
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1answer
25 views

Window air condition location placement question

1800 sqft + basement On main floor 2 window air conditioners 19k btu combined Upstairs 1 5k btu air condition There is 3 bedrooms upstairs, does it make sense to jist pit all the ac units upstairs ...
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0answers
18 views

New XR17/TAM9 HVAC 3-ton installed, return doesn't line up with old one

The return size was 18x24. Not it's 15x15. I haven't paid them yet. Should I demand this fixed before payment is made? I've already brought it up, and he said "nah, it's fine." I hate ...
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2answers
326 views

How to hardwire combined HVAC system for cooling?

I had to borrow the Nest thermostat from one of my units for another one where it was more needed, while a replacement is on the way. The unit from which I borrowed is combined HVAC (heat+cool) with ...
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2answers
136 views

Coleman furnace flame quits after 20 minutes

Coleman DGAA090BDTA furnace flame quits after 20 minutes, below thermostat temperature. Fails after 3 auto attempts to reignite. I power cycle unit, still does not ignite. Wait 15 minutes, ...
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2answers
70 views

After installing a mobile AC, I do have hot air intake from the front door

I have installed an appliance like the following one: Its hose is connected to what acts as the 'chimney' of the building. Now whenever I turn it on, I can feel that hot air is coming from the front ...
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2answers
75 views

Air conditioning fan not turning, motor very hot

The air conditioning in one zone of my house isn't turning. I have a Goodman air conditioning unit in that zone. I noticed that the fan motor was very hot (estimate 150 degrees F). It was much ...
2
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1answer
104 views

AC service disconnect keeps blowing fuses

About 1-3 times per summer the same fuse blows in my AC service disconnect. Always the one on the left. The fuses are 30A and on the panel there are two 30A breakers. The fuse blows typically on a ...
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2answers
74 views

How can I install a Honeywell Wifi RTH6580WF1001 thermostat in place of a Honeywell RTH2300b?

I have separate heating (hot water) and air handler (cooling System). The current thermostat I'm using is a Honeywell RTH2300B and the new one I want to install is a Honeywell Wifi RTH6580WF1001. The ...
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2answers
29 views

A/C intermittently won't cool

I have a 2 zone system that intermittently shows temp 2 degrees or so above set point; on one or the other thermostat, day or night. At some point, the condenser kicks back on and everything works ...
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2answers
80 views

Can I pull a common wire off an evaporative cooler transformer relay?

I have a Nest thermostat currently controlling a LP furnace. The old thermostat didn't have a common wire connected, but there was a an extra wire in the bundle and a common terminal on the furnace ...
1
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1answer
65 views

Why does my thermostat show code 'PF' after running the fan or A/C?

After running either just the central HVAC fan, or the central HVAC AC for just a few minutes, the Bryant thermostat (Model TSTATBBPB101, C Wire attached) screen momentarily shows "PF", and then goes ...
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1answer
59 views

Does anyone know what this pipe is in an HVAC system?

In a new rental (one story, approx 1400 sq ft), one of the bedrooms was not as cool as the other two. I noticed air flowing from the attic door in the ceiling, so went to investigate. The pipe (thin ...
2
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1answer
227 views

Ecobee Smart Thermostat- Using Room Sensor as primary control

This is ultimately a fairly simple question about the Ecobee3 thermostat and the wireless room sensor functionality, but I'll explain my situation first. Twin home, 2 stories + finished below grade ...
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1answer
203 views

Nest thermostat installation to furnace and heat pump

We have T874G1196 thermostat by york (can only find honeywell documentation) MB7BM-1200K-B air handler H8HK015H-21 electric heater Thermopump (heating and cooling) We want to connect it to a nest ...
0
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2answers
54 views

Can the wire from the y terminal on thermostat be connected to the c terminal on heater board as pictures show?

My nest was installed with no c wire and it lost power. At this point the tech looked at the wiring diagram in a/c unit outside but I do not know what he did. A/c worked but later nest had no power. I ...
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1answer
64 views

Should I open my AC register in the basement to help with condensation?

Really hot in NJ this week, excessive heat warnings, and the like. Daytime Temp: 96 degrees Daytime Humidity: 55% Feels Like: 105 degrees Nighttime Temp: 79 degrees Nighttime Humidity: 87% ...
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0answers
16 views

Trane HVAC in horizontal position - why does evaporator throw condensation?

I appreciate assistance from anyone who has had or understands the problem. I have a Trane HVAC system in a horizontal "left" flow configuration in the attic. Ambient temperature is about 95 ...
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5answers
24k 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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0answers
14 views

Low air flow from the 2nd floor bathroom register and I can't find where it connects to the main air supply duct

My air supply system is very straightforward, with an extended plenum in the basement ceiling with 13 branch ducts. But, the house has 14 registers. There are 5 registers on the second floor but only ...
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0answers
43 views

Condo fan coil thermostat fan never turns off, cooling is humid

My thermostat in my condo is a honeywell thermostat and it the only options it has are System and Fan. Fan is set to auto (other option is Lo Med Hi) and the System is set to Cool (or Auto or Off). ...
0
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1answer
52 views

Where to install C wire?

I need to run new thermostat wire since I don't have a C wire to power my smart thermostat, but need some guidance on where to hook it up. I have five wires at my thermostat, two going back to my ...
0
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1answer
38 views

External Air Conditioner Condenser Capacitor replacement

I have a couple of questions about testing and replacing the capacitor on my home heat pump external condenser unit. 1. How can I reliably test the capacitor (what tools do I need?) 2. What safety ...
0
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2answers
102 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 ...
0
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1answer
55 views

Is it more efficient to turn my AC unit off periodically vs. keeping it on only while in the room?

I have an AC unit in my bedroom + workspace. I use its "auto" fan speed and "energy saver" mode (rather than "cool" or "fan only"). I'm wondering, which strategy is more energy efficient and by ...
2
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1answer
80 views

Competing conditioned/combustion air flow; worry about CO?

My home has a partially-below grade basement that has a "Wave" ventilation system that brings cool, conditioned air in from the main house. The basement has an equipment room containing an oil burning ...
0
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1answer
52 views

Half of furnace turned off?

I moved into this house about 10 years ago, I noticed on the furnace that one of the breakers for the electric coils is off with a note saying "Leave breaker off". After cleaning out the blower for ...
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0answers
14 views

water in insulation boards - best method to dry out

I have a horizontal flow brand-new HVAC unit, with a 1" thick insulation board plenum which has had some water ingestion on the bottom panel. The unit is in the attic. I'm quite confident the water ...
0
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1answer
32 views

Could my furnace be leaking due to condensation neutralizer?

I posted this and the main suspect was condensation pump but after troubleshooting, the pump is working fine (tested standalone). Now I wonder if the leak could be due to the condensation neutralizer; ...
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2answers
38 views

Where should my furnace filter go in a Lennox G40UH24A045 series furnace (Merit)?

I cannot find the filter and my furnace is not providing any heat. The limit switch is working fine as is the flame sensor. Diagnostic lights are: 1 slow bling 2 on Any clues? Thanks
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2answers
2k views

how to bypass an HVAC unit float switch (safe-t-switch)

rats keep chewing through the safe-t-switch wires even when I taped them up heavy. before I get rid of all rats I need to just bypass the float switch. at least then I can use the heat while I'm home.
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1answer
76 views

HVAC York diamond 80 furnace A/C

So I have a York diamond 80 furnace and the motherboard burned out so Lowe’s came and replaced it. I’ve been using the heater because it’s winter right now but the other day I accidentally hit the ...
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2answers
104 views

Goodman furnace flames out after 5 mins from cold start

Problem with Goodman Furnace flaming out. After it has been off for about an hour it will flame out after it starts and runs for 5-10 min before it satisfies themo setting. Restarts and finishes cycle....
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2answers
68 views

Central AC Unit - Intake is very cold

So my central AC unit started doing something that I have not experienced before. Once the AC stops, cold air comes out of the intake vent, like really cold air. This has lead to ice forming on the ...
0
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1answer
94 views

Is my furnace leaking water?

I have water accumulated in my basement, that I squeezed out using towel. It was about 8 gallons of water in all. The only source I can see is the furnace whose surrounding is wet but I have never ...
2
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2answers
214 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 ...