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

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3
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57 views

How to repair buckled duct work inside wall?

Background My house was built in the 1930s, I assume these ducts were installed when the home was built. This duct goes from the supply plenum in the basement to the 2nd floor master bedroom. The ...
3
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141 views

Adding vents to duct?

My house has forced air HVAC. When I finished the basement, I used a closed cell foam insulation that worked very well. The basement will get only 8 degrees cooler than the first floor during a time ...
2
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311 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 ...
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94 views

Should I install the jumper on my new limit control?

I needed to replace fan and limit control (White-Rodgers, model 5D51-35), because the fan switch was broken (fan would constantly run) and heat would not stay on. I took a picture of the control, ...
2
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632 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 ...
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26 views

Thermostat and thermostat system for small business with several units and tenants

Am the facilities guy in a small church and pre-school. There are 8 heat pump units through out the church/schoool. Each has a stand-alone thermostat and they are all different. I would like to get ...
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18 views

Single Stage or 2 stage furnace

Just bought a house that has a furnace on last legs. House is 1941 masonry (Chicago). 3 floors: finished basement, first floor, 2nd floor (converted attic with vaulted ceilings and way too hot). Total ...
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27 views

Should I install a doorway fan or dehumidifier?

I have central air in a rancher (one floor), and the living room is on one end of the house. That room is on a slab, and has always been noticeably hotter in the summer and colder in the winter than ...
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28 views

Help AC question

We purchased a home last year, at one time it was zoned with separate AC units upstairs and down. Well a past owner took out the upstairs unit but left the blower in the attic, there is duct work ...
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43 views

A/C still blows when unit is off.

Our A/C is turned off but we still get cold air coming out of the vent diffusers. This is from our downstairs unit. Is that a problem?
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56 views

Can I remove HVAC pipes after exposing the ceiling?

I recently removed the drywall ceiling from my basement and have two related questions about removing the HVAC ducts/pipes. Pictures attached here: http://imgur.com/a/qep4w 1. Is it OK to remove the ...
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35 views

How to Change Chinese HVAC Thermostat

I am looking to put Nest thermostats in the house, I have now found out my entire house (one in each room, 6 of them) has been wired with HVAC Chinese U12A UNIVERSAL A/C CONTROL SYSTEM urrgh – they ...
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80 views

How can I use a portable A/C unit to cool my clean room?

So, I have built a room inside my shop, a clean room for finish and airbrushing. I want to cool this room as I spend more time in it than the rest of my shop (garage) So, I get a portable unit. ...
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187 views

Can't find the circuit board of my HVAC system

I'm trying to install a wireless thermostat for my church building's HVAC system. Currently there is no C wire, so I tried to see where the circuit board was so I could install one. I couldn't find ...
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49 views

Does polarity matter when wiring a humidifier solenoid?

The 56 was receiving 24vac whenever the furnace was on via a red wire and a white wire. 24vac was supplied to the solenoid when humidity was called for via a pair of junction terminals. The 4655 is a ...
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43 views

Should I look into getting an active or passive whole-house humidifier?

My wife and I moved into our place a few months ago. Now that is is winter, the humidity levels dropped down to 20% throughout the house. We want to install a whole-house humidifier to raise it up ...
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54 views

How to clean carbon build-up on Honeywell whole house air purifier made of aluminum?

Bought a house recently that has a Honeywell F300 whole electric house air purifier/cleaner. The cell's aluminum fins have a black baked-on dust that I expect is preventing the unit from working as ...
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45 views

Testing the exhaust of a natural gas furnace?

I recently had maintenance performed on my natural gas forced-air furnace. During this maintenance, the technician went outside and used an electronic handheld device with a wire-attached probe to ...
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78 views

Can ultrasonic humidifiers be used in a bypass setup for a whole house humidifier?

My home is about 3000sqft, with lots of high ceilings. I'm having trouble keeping the relative humidity up in the winter. When it gets down to 10F outside, the RH drops down as low as 25%. This is ...
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28 views

Why is my hydro kinetics system blowing out cold air?

I have a hydro kinetics system that is blowing out cool air when set to heat. Thermostat was replaced when I bought the house a year ago so I don't think that's the issue. Toggle switch is set to ...
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34 views

How can I reduce the noise from an HE boiler vent?

I have a HE boiler that is direct vented out the side of my house on the neighbors side, they find the 'roar' of the exhaust to be very annoying. Have anyone tried troubleshooting these to ...
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161 views

How can I install a furnace register in a kitchen-cabinet toe kick?

I'm planning to install new kitchen cabinets. I'll be covering up the kitchen's existing sidewall diffuser with new cabinets, so I'd like to relocate it to a new register in the toe kick of the sink ...
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996 views

How can I tell if my bathroom ceiling vent is working properly?

Seems to take the vent forever to clear shower vapor from room. I purchased a vent that had a good rating. It is vented to the outside. How do I know if it is working properly and actually venting to ...
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1k 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. ...
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89 views

How do I troubleshoot my central A/C?

It's 79 outside right now. It's been running for hours and it's remaining 79 inside. I'm in a brand new 2 story home in Monroe, OH. It has rained a lot recently but I just feel like it should be ...
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93 views

Why doesn't my A/C get power when using the alternate C-wire thermostat hook-up method?

I changed my old Honeywell thermostat for a new Honeywell WiFi thermostat. I installed it just as the directions stated. I used the alternate C-wire method as the old unit did not have one. ...
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2k views

How do I size a wall sleeve for a through-the-wall air conditioner?

We are shopping for a through-the-wall air conditioner. We do not currently have a hole in the wall with a sleeve in it. We are trying to figure out what sleeve to buy. The air conditioner we like ...
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1k views

What's causing my draft inducer to stay on?

I have a new, 3-year old, high-efficiency, gas furnace in my home. I recently realized that my draft inducer, which normally kicks on before the burners and before the main blower, is not stopping. ...
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946 views

How can I properly drain heatpump condensate?

I have a heat pump in the attic That drains to the ground outside two floors below. I naively added a hose fitting so I could redirect the water where I wanted it, slightly up hill. This created a ...
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12 views

New Common Wire To Programmable Thermostat-What Went Wrong?

Any help with this problem would be greatly appreciated! I've read a number of the related posts so if you're reading this, chances are I have already benefitted from some of your wisdom. While ...
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23 views

Ac running but my blower will not

My ac unit stopped feed cold air from the unit outside. The main fan on top is spinning fine and my lines are freezing but the blower in the unit is just barely turning. Can someone tell me what would ...
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23 views

Older home with no AC plenum…replace our entire AC system as suggested?

We have an older home that has a large living-area/fireplace room; the AC unit sits over it in the attic. Earlier this year, in that room, we noticed a crack beginning to form in the ceiling sheet ...
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0answers
20 views

Goodman A/C unit sparks at high pressure line on furnace. Blows breaker

Got a 10 year old A/C unit and notice breaker blown. Flipped breaker and noticed a spark where the high side line goes into the plenum of the furnace and the breaker blew again. A/C repairman checked ...
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0answers
29 views

Furnace not working

I came home to my furnace having no power even to show trouble codes. I turned off my breaker opened the blower door and it had a blown 5 amp fuse on the curcuit board. I replaced the fuse turned the ...
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0answers
18 views

Why does my furnace blower motor stop working after 20 minutes?

The furnace blower motor stops working after 20 minutes, but the central air unit outside continues to run. The blower motor will not start again until after it has cooled off or unless I assist the ...
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37 views

What could cause a 5 ton Goodman packaged unit on the roof to turn on and off randomly?

With the thermostat on cool and manual the unit (fan + compressor) will turn on sometimes right away, and sometimes after hours. Then it'll run for either minutes or hours before turning off, either ...
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20 views

AC fan not turning on. It's silent

Replaced the capacitor 2 weeks ago because AC (Lennox) outside fan was not running, blowing in warm air. And the unit started working. Then again yesterday (95F outside) same thing. Replaced the ...
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35 views

Why would a blower motor work with A/C, but burn out with furnace?

I've gone through 2 blower motors since I purchased the home 3 yrs ago. I never have an issue with the blower when the AC runs; but it keeps dying in the winter with the furnace. I've had 2 HVAC ...
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32 views

Why is ERV (return-return) installation not recommened?

I just had an ERV installed I was expecting the install to be return-return (ie indoor air from return duct pushed outside, and outside air pushed back into return further down the return). The ...
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0answers
50 views

noisy Air-conditioner compressor

I bought a new split AC that worked great for a week or so, but now I can hear some annoying noise coming from the outdoor unit. The outdoor unit in installed on a flat roof so I can hear this noise ...
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0answers
21 views

How to connect honeywell wifi thermostat to trane A/C unit

My current system has 4 wires to the thermostat. I need to add the C wire for the new honeywell wifi thermostat. On the wiring board of the a/c I found 26vac on one terminal. The red wire to the ...
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0answers
31 views

Moved thermostat now ac wont turn on

So i was moving my thermostat to another room. I cut the wire to splice a new wire in. I got zapped first then spliced the wire. Now my thermostat is good to go but when it calls for the ac to kick on ...
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0answers
75 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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61 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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0answers
50 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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0answers
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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84 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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0answers
46 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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0answers
34 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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26 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 ...