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

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connecting into 24v on HVAC transformer [duplicate]

I've located available 24v to tap into on my transformer but what's the physical procedure to add my tstat wire for C?
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77 views

Will a DIY Air Conditioner help my HVAC Central Air system?

So the husband and I just moved to Texas. We went away for the weekend and turned our HVAC central air from 68F and ON to 75F and AUTO. For some reason when we got home the AC wouldn't drop. Now I ...
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1answer
30 views

Just installed central 4 ton fau condenser and evaporator but don't know how to install thermostat from condenser to fau to the thermostat

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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62 views

how to install a casement window ac unit in a standard horizontal window?

Ok... I have scoured the internet. I was given 2 casement window ac units. Both of my heat pumps were stolen and this is an army wife turned widow make do type situation for while I save to replace ...
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2answers
84 views

Issues after capacitor replaced on AC unite

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 built 6 yrs ago) ...
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2answers
134 views

No AC. I have a few HVAC troubleshooting questions

I'm having issues with my AC. Basically, the symptom is that I feel cold air coming out of the vent, but it has no pressure, almost like I have to put my hand IN THE VENT COVER to feel any cold air. ...
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1answer
151 views

ecobee3 Installation - Thermostat Y Terminal (yellow) Wire Connects to C Terminal Board

enter image description hereI'm attempting to install a new ecobee3 on an older Coleman Evcon gas furnace and AC HVAC system. The system is what I would consider typical residential as far as I can ...
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52 views

My A/C Unit stopped working after replacing blower motor

Any idea what I may have done wrong here or how to check? I replaced my blower motor (it was 100% compatible and had the proper capactitor), and upon starting it up the blower did nothing and the ...
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25 views

Residential HVAC: one main thermostat, what do the other thermostats in the rooms do?

Are the other thermostats only meant for non-force air heat only? Does it mean only one thermostat in the house needs to have both heating and cooling, and auto or fan-only switches? It sure make ...
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87 views

replacing single pole York A/C contactor

I am trying to replace a single pole contactor with burned contacts on York package unit Model D3YS030N064069. The old contactor has four 24 volt lugs on one side. The new contactor has 2 on each ...
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1answer
55 views

Bring HVAC Ducts to the Ground?

I'm finishing my basement. Is there any benefit to bringing the vents from the basement ceiling to the ground after I finish framing?
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47 views

Changing Trane Baystat240a to another thermostat

I want to change my current thermostat to a programmable electric one (no batteries). Could someone verify if it does have a common wire and if all wiring could fit modern thermostats? Looking at the ...
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1answer
244 views

Need to know where to connect my C wire [duplicate]

I had the extra wire in the wires run from my thermostat to my A/C, but the old thermostat did not need the C wire, so it was cut and stuff on both ends. While installing the new thermostat I ...
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35 views

How much refrigerant in an average 12 cu. feet freezer?

How much refrigerant goes into a 12 cu.ft chest freezer? On the nameplate it says ______POUNDS ___16___OZ (nothing written in front of pounds) is there really only 16 ounces of refrigerant in those ...
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2answers
242 views

G to C trick not working for cooling. Honeywell RTH9080WF

My electric furnace has no c terminal. Furnace is heat & cool both. (Lennox Electric Fan coil Model CBS18-21-3P). I installed Honeywell RTH9080WF. I switched G to C on my thermostat and got the ...
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2answers
125 views

How to repair pierced refrigerant line in chest freezer?

My idiot friend was screwing brackets inside an ice cream freezer with self-tapping screws, and one of the screws pierced a copper line containing refrigerant. Apparently it made a crazy hissing sound ...
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27 views

HVAC 3A fuse shorting on cool

I recently came back from a trip, and the thermostat was still working. On turning the AC on, the wall-powered thermostat decided to die. Upon investigating in the attic, I noticed the 3A fuse had ...
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20 views

Can I add another heat run to my furnace?

I'm looking to add a bedroom to the basement and would like to add a heat run to the new room (return air will occur through an opening between the ceiling joists). This seems easy enough, but I ...
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1answer
128 views

How to fill / seal in-slab hvac ductwork?

My house is built on a slab. Within the slab are "channels" which act as ducts for the HVAC system. I assume it is partially lined with metal but based on photos from an HVAC-cleaner, it's hard to ...
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35 views

How to fix uneven central heating and air?

My central heating and air conditioning system does not heat my home evenly. Half of the house gets significantly warmer / cooler than the other half. I have tried adjusting the registers, but to no ...
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16 views

Will a Carrier heat pump generate hot air in the heat mode if the compressor is bad?

The heat pump works ok in putting out heat, but puts out hot air in ac mode as well. Had an hvac tech look at it. He replaced the capacitor and said the compressor was bad. Can the heat pump put ...
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59 views

Adding dual zone capability to an existing HVAC system in a house with existing 2 zone manual ducting

I have a house that has existing dual zone ductwork in place (separate ductwork for the upstairs and downstairs) that has manual dampers. I recently replaced the HVAC system with a new geothermal unit ...
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62 views

Troubleshooting pressure error code for Trane XV80

I have a ~7 year old Trane XV80. Recently, it started throwing up the pressure error code (3 flashes). Inducer fan would start, but the burners wouldn't light. Being lazy, I would basically power ...
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1answer
531 views

Can I connect two wires to a single screw terminal in my HVAC system?

I am installing a new honeywell WiFi thermostat but the old battery operated thermostat had batteries and no "C" wire. I look at both the thermostat and the air handler and found an extra un-used blue ...
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5 views

No “C” terminal on Trane air handler [duplicate]

I am installing a new honeywell WiFi thermostat but the old battery operated thermostat had batteries and no "C" wire. I look at both the thermostat and the air handler and found an extra un-used blue ...
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1answer
158 views

heat pump/air conditioning wiring to thermostat

We decided to change the thermostat of our heat pump/air conditionnning unit. First 3 images are the old unit. The first 3 wires(1 and 2 picture) yellow red orange were not connected to anything, just ...
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1answer
103 views

Smart Thermostat - No C-Wire - No Controller Board

This one seems to be a little different from previous questions on the subject. Here is the dilemma, I don't see a transformer. I have included a few pics. There are Three wire bundles. For ease ...
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154 views

Why would my AC turn on and off randomly?

My AC unit turns on and off randomly regardless of whether the thermostat is set on or off. I've even tried removing the batteries. Does anyone know why this might happen?
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156 views

Would increasing the size of the A/C duct for my kitchen improve cooling?

As part of an ongoing kitchen project, I'd like to relocate the existing a/c register in the ceiling (which is located next to an interior wall) to the center of the room and upsize the duct (and ...
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2answers
93 views

Why do I have to start my furnace manually every morning?

The oil furnace works fine all day and evening, then overnight I have the programmable thermostat lower the temperature at 11pm. But every morning at 5am when the thermostat tries to turn the ...
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0answers
39 views

What to look for in central air installation?

I'm having an HVAC company install a York central air unit in my house today, and I'm wondering what things I should be looking for in the quality of the installation? Existing York central heating ...
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1answer
125 views

Fan coil wiring problem with new thermostat

I'm trying to upgrade to a new line voltage thermostat. The new thermostat has many more connections, including three fan speeds. My current system has a manual fan switch on the wall so all I need ...
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32 views

Why does the A/C come on downstairs when heat is on?

I just moved in to a 2-story house. It is zoned upstairs and downstairs. If I turn the downstairs thermostat to OFF and the upstairs to COOL, the HVAC in the attic comes on, the outside compressor ...
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18 views

What could be causing my goodman furnance to not work?

My furnace starts, than the blower motor runs constantly, but trips out on roll out limit switch. The air inlet and outlet lines appear to be unobstructed, but when it shuts down there seems to be ...
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47 views

Baseboard heat not keeping up

This is my first winter in my house which was built in 1991. A Navien CH-240 that provides both hydronic baseboard heat and hot water was already installed. We have two zones, upstairs and downstairs. ...
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74 views

Furnace blower intermittently stops working

The blower on my furnace is set to be on constantly. The last two nights in a row I have woken up in the middle of the night to hear that the blower is not running and that the temperature is dropping ...
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15 views

What could cause my Trane furnace to not light?

after I set my thermostat for heat the combustion fan motor comes on but the burners does not fire, and after like two minutes everything turns off and the LED flashes two times, which means SYSTEM ...
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19 views

baseboard heat problems it makes loud noises and does not heat 2 zones at the same time

The baseboard heat will heat the main floor and not the upstairs and vice a versa. What could be the problem, it also makes loud noises.
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200 views

Is it normal for this PVC pipe to be dripping from under the eaves?

I have a 2 story house, 14 yrs old. There is a PVC pipe under the eaves over a window on the 2nd story, that has been dripping more than normal the past couple of days. Our AC unit is located in the ...
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20 views

What type of control systems are available for a home with multiple HVAC systems?

Our new (used) home has two HVAC systems, one for upstairs and one for down. There is a thermostat in the dining room, which is directly affected by sun. And one in our bedroom, that clicks all ...
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12 views

old furnace and thermostat upgrade

In a furnace that has no circuit board, can the C wire be connected between the C terminal on the thermostat and to one of the contact leads on the 24V transformer and operate safely?
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1answer
107 views

The hot water is working but the radiators will not heat up!

We have a Utica Boiler model number SFH4150WT and we are receiving hot water but the radiators do not heat up!!. We tried bleeding the radiators, they only heated up a little bit but after about 5 min ...
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1answer
295 views

Will splitting a duct to extend HVAC to an addition cause problems?

I'm building a 15 x 26 addition off of current family room to use as a music room. The family room has 2 vents(registers) where the family room meets the new room, and because of convenience they ...
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39 views

How do I measure the size of a duct that runs through a finished wall (the register end is accessible)?

I am trying to redo a Manual D for my house (heating mainly). I can pretty much determine the length of each run but I can't figure out the exact size of the ducts that are already installed The ...
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44 views

What size exhaust fan do I need for a pool house?

What size exhaust fan ( how many CFM ) do I need for my pool house . The pool is 36 feet x 18 feet x 8 ft deep, and is kept at 32 C. The building is 42 x 28 feet, 10 feet high ceiling, all insulated, ...
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58 views

What could be the reason why all my registers at foundation slab level have weak air flow?

In the picture below all the ducts that have a long leg going toward foundation have weak air flow. Read the details on the picture Could anybody tell me what is the problem with these guys? The ...
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60 views

How can I adjust a whole-house ventilation bathroom exhaust timer?

We have a home built in 2008 in west-central Minnesota. As a cost-saving (I perceive it as such, and may be mistaken) measure to fulfill air quality and venting code, the builder set up an upstairs ...
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71 views

Whole house humidifier - can you use a steam/mist with a heat pump?

Just moved into my new house and first time with an electric furnace and forced air with a heat pump (rheem) - and immediately we noticed that our skin is super dry and cracking. I was looking into ...
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55 views

HVAC ducts ready for finished basement?

I'm starting to finish my basement. Before I do so, I want to be sure the ductwork is sufficient to keep it warm during Colorado winters. The basement was finished when we moved in, but gross, so we ...
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1answer
655 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 ...