Questions tagged [hvac]

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

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2answers
56 views

How to clean a reusable HVAC filter

My HVAC system is around 15 years old and I have a washable air filter. The tech who looked at it last told me to clean the filter out and run water through it once a month. He told me to let the ...
3
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1answer
93 views

Can I change an orifice to make an R22 evaporator unit compatible with a 410a unit?

I have an R-22 system that was never hooked up or run. It was put in place and then the project was put on hold for several years. The outdoor condenser unit is no longer available obviously. We just ...
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1answer
52 views

Ductless AC Initial Charge

I just purchased an LG mini-split set: 18,000 BTU indoor unit https://www.supplyhouse.com/LG-LSN180HSV5-18000-BTU-Ductless-Standard-Multi-F-Air-Conditioner-Inverter-Heat-Pump-w-Built-In-WiFi-Indoor-...
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1answer
28 views

AC Unit Not Cutting On

My AC unit has the thermostat indoors, a unit in the crawl space and the outdoor unit. Everything was working until I had a contractor come out and add insulation in my crawl space. Now the heat/air ...
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0answers
26 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 ...
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1answer
10 views

coleman/york furnace 7 red flashes

My furnace "fails to start" 3 times, then it flashes 7 beeps and quits trying. I can hear it start then the flame "just stops" 3x in a row. What gives?
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1answer
54 views

Flexible round duct - What to use

I'm re-routing some 10x3.25" duct through a bulkhead in my kitchen. Planning to change over to 6" round duct for a 4' segment that is relatively straight (no 90s). It was my intention to use non-...
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0answers
25 views

How can I hot wire my AC unit from my furnace without a hot red wire?

My power control board inside my furnace seems to be broken and a service technician cannot come out until after the memorial day weekend. My thermostat is not receiving power. Using a multimeter I ...
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2answers
139 views

Unthreaded holes for AC fan motor mounting screws?

My AC is not working. It is a Trane AC (Model 2TTB0030A1000AA). In the process of diagnosis I tried replacing the capacitor, and that did not help. I tested the fan blades and they no longer spin ...
2
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1answer
40 views

Do any home thermostats have an adjustable control range?

I am having trouble with AC and need to replace it soon ; so I have been listening to it cycle .I knew it only stayed on a short time but I just found it runs less the 2 minutes ; that is with ...
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1answer
66 views

Sealing a closet door that has a gas fired water heater in it

Does anyone know how to make a self sealing door? There's a bedroom in my basement, and it has a door in there that allows you access into the HVAC room (which can be entered from another door in ...
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0answers
29 views

Air conditioner will not shut off

I cannot get my air conditionar to turn off at the thermostate. I turn it to off or auto and it still runs. I have to flip the breaker off to get the unit to turn off. What could be wrong?
2
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2answers
74 views

Should I insulate metal duct work in basement?

I have a balloon frame house with an unfinished basement. The air handler and furnace are in the basement too. Last fall, we had the duct work removed because it was wrapped in asbestos tape that ...
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1answer
32 views

Replacing A/C thermostat

I think that my mother has a bad thermostat. When the A/C is turned on, the furnace blower works but not the outside unit. However, when I press the contact switch (outside), both the compressor and ...
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1answer
65 views

Two HVAC units on one condensate drain line

I am renting a house with two HVAC units - one upstairs and one downstairs. There were two condensate drain lines (one per unit). The units were older so when they quit working efficiently the ...
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1answer
31 views

Blower Motor Heat and Cool Control Board

I’m an electrician by trade but i have a friend who needed his blower motor replaced. The parts store sold him a motor but it only has one hot leg. The control board has a hot for cooling and a hot ...
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0answers
31 views

Installed Honeywell R8285A 1048 control center combined with a Honeywell PRO 8000 thermostat

to operate an inline duct fan on a long run to a new addition. Thermostat in the new addition activates fan when the thermostat is set to cooling perfectly. I can use it to manually turn on the fan. ...
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1answer
48 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 ...
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2answers
78 views

I have an unused C wire hooked up to thermostat and have no idea where to connect it to the furnace for power

I know this question gets asked all the time but I've spent hours staring at forums as well as my furnace and at this point I'm desperate. I just bought a nest thermostat that needs a C wire ...
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1answer
50 views

HVAC blower fan won't stop

FINAL UPDATE: I have found the culprit - the Nest thermostat itself. First, I disconnected the t'stat at the control panel and found out that the fan would no longer start upon powering the system. ...
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1answer
77 views

Need to identify wires coming from external AC Unit

idiot DIY'er here :P. I recently installed a smart thermostat and long story short; I removed the two wires from my furnace's board for the external air conditioning unit in the process. I was going ...
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2answers
42 views

a/c doesn't turn on when temperature is reached

I just changed my thermostat and it does the same thing [as the old thermostat did?]. I get up in a.m. thermostat is set at 77 F. When inside room temp reading on the thermostat reaches 77, a/c doesn'...
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1answer
55 views

Cutting 4" hole on Rim Joist

Would it be advisable to cut a 4" hole on the basement rim joist to install a bathroom fan. The joist size is 8" and is supported by a basement wall.
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1answer
50 views

Remove switch that controls thermostat

I recently bought a condominium in a large building, built in 2005. It has a single thermostat, and the thermostat works fine. But right next to the thermostat, there is a switch. It looks like an ...
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1answer
28 views

a/c condensation line not draining

I have a unit that is installed in the attic and is about 2 years old. For the first year everything was fine and then one day it wouldn’t run. So I hooked up the shopvac and sucked the condensation ...
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0answers
15 views

Ac unit blower cuts on off on off

My blower fan cut on off on off on off that fast then it stays on and runs fine. Only dose it at the beginning of the cycle
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0answers
18 views

Name of A/C hose fitting

I have a set of R134A manifold gauges that I would like to use to pull a vacuum on an R410A system. My hoses terminate at the R134A quick connector with the threading on the right of the attached ...
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1answer
31 views

Old furnace with extra wire, but no c terminal Janitrol, 19 year old furnace

I've searched multiple threads regarding this, but I didn't manage to find any that seemed to match my use case. My board doesnt have a C terminal, and it doesn't have the other terminals connect to ...
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0answers
24 views

How do I plug an old duct

While renovating my kitchen, I came across an old exhaust duct in the wall. It goes through the chimney bricks and into the interior of the chimney. The boiler uses a duct within the chimney that is ...
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1answer
54 views

Overflow line tied with Condensate Line

had a house inspection done and the inspector told that Irregular materials were used, I am attaching a pic. how much work is it to repair it? is it a easy fix? Thank you
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1answer
28 views

Can I safely jumper between either G or Y and RC at thermostat panel to troubleshoot AC problem?

I'm trying to troubleshoot a non-functioning AC. The fan does not come on and there is no cool air/condenser does not run. My thermostat is a Braeburn. Three things I'd like to try for ...
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0answers
34 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 ...
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0answers
42 views

Is this where my HVAC air filter goes?

I moved into a home that was poorly taken care of by the homeowner before. It dawned on me today that I've never replaced the HVAC filter (I guess I'm bad at taking care of the house too :) ) in the ...
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1answer
41 views

Furnace with no “C” connection

I have a mobile home furnace. This furnace only has a 4 wire connection terminal, G,W,R,Y. I also have a condensing unit outside with the 24 volt 2 wires coming to the furnace. I know I connect one to ...
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0answers
40 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 ...
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5answers
69 views

How to size a whole house fan?

I'm in the middle of a home addition and am thinking about adding a whole house fan. The finished size of the house will be about 2000 square feet - approx 1500 on the main level, and 500 on a lower ...
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0answers
20 views

HoneyWell baseboard thermostat

Hello everyone! Need some help here (trying to help a family member) They recently purchased a home that has a furnace and AC ( with central air) in each room there at these honeywell thermostats. ...
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1answer
35 views

Why doesn't my HVAC system use the away temperature setting?

I have a Carrier Infinity dual-fuel 5 stage HP w furnace. I set the away temp much lower than the home temp but the HP keeps running to bring the temp up to the next home temp. I would think the ...
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0answers
15 views

Lennox Furnace Troubleshoot Assist

I have a Lennox Elite G50UH-24A-070-15. It quit entirely and threw the error "Pressure Switch open or blocked" according to the diagnostics panel on the front. Recent renos so thought it was clogged/...
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1answer
34 views

How should I support rectangular duct in wall?

In California, I'm installing a 3x14 rectangular supply duct from my attic to my first floor. It goes vertically through the second floor wall, through the floor, and ends in the first floor ceiling. ...
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0answers
22 views

Draft Inducer Takes a Long Time to Start

When I turn the thermostat up I hear the draft inducer relay click, but the inducer motor doesn't start immediately like it used to. There's quite a lag time before I hear the draft inducer fan start ...
1
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1answer
60 views

Converting I+ I- thermostat to 'standard' wiring

I've been replacing my thermostats with the RadioThermostat CT50, which reports to my home-brew home control/alarm system. I have a 3-year old AireEase 4-ton unit in the shop that has a Comfort Sync ...
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0answers
33 views

AC Goodman unit not powering on

Is getting hot and I tried to power on my AC unit, it only blows warm air and no sound from unit outside, fan is not moving, no noise. Checked indoor fuses were on and reset them Checked outdoor fuse ...
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1answer
67 views

convert a onan 110v generator to 220v

My RV has roof-top air conditioning units. The generator will run 2 units. I would like to convert the RV to a mini-split system with 2 air handlers. They require 220V, and draw 25 amps; however my ...
14
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6answers
4k views

Is Electric Central Heating worth it if using Solar Panels?

I understand that electric heating is less efficient and comparatively more expensive than gas heating (propane or natural gas), but considering I live in Texas (a lot of sunlight) and I intend to ...
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1answer
16 views

Furnace burners shut off an hour after running?

Older furance that wasnt holding pressure. Leak was found and gas valve replaced. Gas is on. Fired it up yesterday for the 1st time. The house has been vacant awhile. We had no problem. Came ...
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2answers
47 views

A/C blower does not work after a power surge

My outside unit works but my inside unit does nit turn on, its a bryant a/c system. On the unit it says the circuit board is built into the blower motor. The transformer buzzes. Can I replace the ...
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0answers
17 views

Furnace limit switch only reading 12 volts, I have 24 volts coming out of transformer

12 volts at primary limit switch, 24 volts out at transformer 24 volts at c & w terminals when stat calling for heat. furnace will not light, trouble codes call for bad primary/secondary limit ...
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1answer
42 views

C Wire in Air Handler

Can someone please help me find where to connect a C wire for my smart thermostat? Here are some pictures with descriptions. It is difficult to get to the 24v connection in the back. My schematic ...
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0answers
24 views

Circulating main floor AC to above and below floors

In the summer the main floor with the AC is always comfortable, the basement is a bit warmer and the 2nd floor unbearably hot. I'll be adding more insulation under the roof to help, but short of ...