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

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0
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2answers
59 views

Is it possible to create a better temperature controlling system?

I have a two story 2.5k sq ft house with a varying degree of temperature throughout the house. The main problem is that the air coming out of vents are very weak if almost nil. Only the living room ...
1
vote
1answer
64 views

Is this HVAC capacitor dead?

HVAC system stopped blowing cold air today. Last time it did this, we gave it a 2-3 hour break, in case it was over-heated, and it came back. Today, same deal, but no cold air after a few hours. I ...
0
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0answers
138 views

possible HVAC Selector Wiring Solution?

I moved into my current home last winter. This house has an old zone controller MasterTrol Mark V model Mabs-V-3. UPDATE: just found that all wires connected to M? end nowhere. So I remove all the ...
4
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2answers
928 views

Connection for C wire on Mastertrol Mark V zone control panel

I have spent hours searching the web for information on this 20+ year old zone control panel, which supports 3 zones of Heat and A/C. The thermostat I'm replacing (on Zone 3) connects to T4/T5/T6 as ...
0
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0answers
24 views

Electric HVAC unit runs and stops randomly

I just turned on my heating unit for the season and it seems to be running and stopping intermittently. I'm not sure if this something to be concerned. This happened last season as well and I called ...
2
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2answers
88 views

Can I remove the insulation from flex duct

I am trying to fit a 7" flex duct between some floor joists and it would fit better without the insulation. Can I remove the insuluation and just use the plastic part?
2
votes
1answer
5k views

Why won't my Heil 7000 natural gas furnace ignite?

I have a Heil 7000 gas furnace Model: NUGK100DH12 Serial: L933050100 When we turn it on at the thermostat, the exhaust blower will kick on. We checked to be sure the gas is reaching the unit and ...
1
vote
1answer
87 views

Foil tape failure in HVAC unit

On a recent trip up into my attic, I found out that the air conditioner was blowing cold air into the attic. In several places at the AC unit, the foil tape had become unsealed. In the interest of not ...
0
votes
1answer
57 views

Should my A/C compressor come on when I turn only the fan on?

I have a bog standard HVAC system with a Nest thermostat. When I tell the theromostat to turn the fan on for 15 minutes the A/C compressor also kicks on. Is this normal?
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4answers
134 views

Running air handler condensate drain into sump?

The condensate drain from our air handler now runs across the wall and into the laundry sink. This is stopping us from attaching shelving to the wall. I noticed that the sump pump pit is right next to ...
1
vote
1answer
125 views

How do I reinstall round 6" duct pipe in my basement?

The 6" duct pipe was removed in my basement. I am trying to put it back up, but the pieces will not go together. The pipe is no longer round, and even when i try putting pieces together that have the ...
4
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3answers
928 views

Is there a trick to getting round HVAC duct pieces to fit together

I have been doing some basic HVAC duct work as part of a remodeling project and I can never get the pieces to fit together without massive amounts of elbow grease and mangling the ends. Is there some ...
0
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0answers
36 views

Central AC is Icing up, but not cooling my house

My central air conditioner isn't cooling like it used to. I noticed that the refrigerant lines entering the evaporator coil in the plenum were icing up. What might the problem be?
1
vote
1answer
218 views

Replacement thermostat wiring

I have an American Standard heat pump AC. I'm replacing a White-Rodgers manual thermostat (where I move a switch from cold to heat) with a Honeywell RTH7600 (which will automatically switch from cold ...
0
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0answers
32 views

Why is my A/C's breaker tripping all the others?

I noticed the A/C wasn't coming on - even the outside compressor - so I checked the breaker and the two switches that the A/C is on were tripped. At this point no other breaker was affected. I went to ...
0
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0answers
247 views

Furnace not working properly with digital thermostat

I have been attempting to use several different types of digital thermostats to replace my old mercury thermostat, however none of them are able to control the furnace properly. All of them are able ...
1
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2answers
30k views

Why won't my A/C turn on after I replaced the thermostat batteries?

Our thermostat died yesterday, but after replacing the dead batteries with fresh batteries, and confirming the LCD screen was operable, our AC no longer turns on. I have attempted a factory reset on ...
1
vote
1answer
102 views

New condenser fan motor burned out

AC technician replaced my condenser fan (through a home warranty service). The new fan worked for 5 min and stopped working after that. the fan motor was extremely hot (180F or more) The old fan motor ...
0
votes
1answer
46 views

Should I add an escape register for added ventilation in A/C duct to reduce condensation?

I have a condensation and drippage problem where my 8" exposed circular AC duct comes out of the ceiling. Above the ceiling is the attic, meaning it gets pretty hot. The pipe comes out of the ceiling ...
2
votes
1answer
92 views

Is there a reason for an exterior vent not connected to anything?

I have an exterior vent on the side of my house not connected to any piping within. You can look inside and see wood/concrete/insulation into the cavity between the basement ceiling and main floor. ...
2
votes
1answer
103 views

Can a problem with heater stack liner cause outside chimney mortar to crack and fall out

I had "high-efficiency" furnace installed in 2009. In 2011 chimney required full grind-out and repoint job, and chimney saver solution was applied to prevent water damage. Service lasted only 18 ...
0
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0answers
53 views

Which should I do first? replacing furnace or resurfacing concrete floor?

I'm going to get two things done in my basement soon (by hiring professionals), but I'm wondering what the right order of operations is. One task is to replace the gas furnace that sits near the ...
18
votes
1answer
11k views

Humidity Levels

What is a healthy and safe humidity level that I should try to keep my house at?
-1
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1answer
42 views

What is wrong with my air conditioner

I have been using my air conditioner on and off all summer. The weather hasn't been really that bad this year. But now that the weather is reaching high 80s, my air conditioner decides to die on me. ...
2
votes
1answer
1k views

What can cause an A/C to freeze up

Our A/C evaporator coil freeze up last year, so I called out a technician. He said that it was charged with the proper amount of Freon, and my problem [paraphrased] "something had narrowed the inside ...
7
votes
5answers
12k views

How much cooling can I expect from a central air conditioner?

Yesterday's high was 106.0F, low of 79.2F, full sun all day. AC set at 78F, indoor temperature reached about 85F. Today's high was 105.4F, low of 81.1F, full sun all day, now about 102 at 7pm. AC ...
1
vote
3answers
610 views

Electric panel distance from windows and/or gas service entry

I can't find anything specific anywhere else, but what is the minimum distance a main electrical panel can be from a window when the panel is mounted on the outside of the house? Additionally, is ...
0
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2answers
100 views

Home inspection requires exhaust to attic exterior

We have sold our 1995 built home. One item that needs to be addressed is "Bathroom fans vent to attic and need to exhaust to the exterior of the attic to prevent moisture condensation in attic." I ...
1
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1answer
316 views

Air handler condensation draining problem

For the life of me, I cannot figure this out. My air handler and heat pump were installed in 2006 and work great. For the first summer since I've owned the home, condensation started to not drain ...
0
votes
1answer
181 views

Furnace filter inserted backwards, will this cause permanent damage?

Just found out that my wife changed the last furnace filter and inserted it backwards. This was noticed after the ac was not cooling the house very well. I went outside and noticed that the coil ...
0
votes
1answer
125 views

How to connect a DIY thermostat to the HVAC System

I am building a DIY thermostat similar to this blog. I want to connect it to the HVAC system of my home. How do I do that? I found this post which is very informative but doesn't completely answer my ...
0
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0answers
21 views

Need to run a “C” wire to thermostat but control board has no “C” [duplicate]

I am looking to replace a thermostat with one that needs a C wire... which my current thermostat does not. I have some extra wires in the thermostat wiring that are unused... so I went down to the ...
6
votes
3answers
1k views

How do outdoor mist-cooling A\C units fare in real-world usage?

I live in Phoenix where summer outdoor temperatures regularly exceed 110°F and humidity around 15% or lower is not uncommon. In this environment a mist system can easily pull the temperature down ...
1
vote
1answer
80 views

A/C Unit Has Leaking, Has Ice Buildup

Came home yesterday to find that the house was burning up and the thermostat had automatically switched itself to heat... in the summer! We didn't know what was going on, and assumed some sort of ...
1
vote
1answer
111 views

What could cause a heat pumps line sets to be the same temperature when running?

The symptom I'm dealing with is that the heat pump system isn't cooling as much as it should. Tested it today, was about 79°F inside and outside; system was blowing air at about 73°F. ...
5
votes
6answers
16k views

How often should I run a bleach and water solution through condensate lines?

How often do you need to run a bleach and water solution through the condensate drain lines (of a heat pump) to keep the bacteria away? What are the recommended parts (e.g. 1 part bleach, 10 part ...
1
vote
2answers
63 views

What can I do to avoid tripping over HVAC drain line?

The drain tubes for the Furnace and AC run about 10 feet across the laundry room to the drain in the middle of the floor. Unfortunately this is a fairly high-traffic zone (seven people living in the ...
3
votes
2answers
395 views

Can a HVAC solve my ventilation problem?

I have a problem with my house such that with all my windows and doors closed the house smells and the air feels stale. I'm thinking of purchasing a high efficiency HVAC to vent the stale air out and ...
0
votes
0answers
124 views

Thermostat replacement

My old thermostat is a carrier t-stat and has a jumper wire between o/w2* and L I am upgrading to a honeywell wifi t-stat, should I install the same jumper wire on the new thermostat? I have an ...
1
vote
2answers
421 views

Undersized AC - Options?

Background: Our two-story house is about 3,000 square feet. When we bought it last year, it had two separate AC units, a 2.5 ton and a 4 ton. They were both old and died last month. We had them ...
0
votes
1answer
219 views

Inverter air-conditioning units or non-inverter air-conditioning units?

I want to purchase new 8-9 units of air-conditioning for my new house. For the hall, kitchen and all the bedrooms. Some people say inverter air-conditioning is only suitable if you are using more ...
7
votes
6answers
10k views

Where should my furnace filter go in a Lennox G40UHX series furnace?

I have a Lennox G40UH(X) series furnace, which is installed in our attic (We have a single-story house on a slab). Because the furnace is installed in the attic, it is "laying down" on its side, and ...
11
votes
2answers
11k views

Why is my Nest thermostat not working with A/C?

I installed Nest thermostat a few weeks ago, replacing an old Lux programmable thermostat (there was nothing wrong with it). I connected 4 wires (R,W,Y and G) to the Nest. But as soon as I'd ...
1
vote
2answers
809 views

Wifi Thermostat wiring

Replacing 2 Hunter thermostats with a Honeywell RTH9580 Wifi. Neither unit has a C wire - I'm comfortable with the upstairs high efficiency unit, but the downstairs older unit has thrown me for a ...
3
votes
2answers
627 views

Can I use an unused wire as a “C” wire?

I just bought a new thermostat that is Wi-Fi enabled and it requires connection to a "C" wire. The old thermostat does not have one running to it, but there are other unused wires. The thermostat ...
2
votes
0answers
86 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, ...
4
votes
3answers
4k views

Why does the pilot light go out when the furnace is running?

Every time the furnace fires up, it blows out the pilot light. Sometimes it will run a full cycle and blow out when it shuts down, and sometimes it will blow out about a minute into the cycle. We ...
4
votes
1answer
3k views

What would cause my furnace to only work with the filter removed?

My Carrier furnace works fine without the air filter in place on the return. With the filter in place it works for a while and then stops with a complaint about "limit, or flame rollout is open" ...
3
votes
2answers
4k views

What would cause a furnace to shut off prematurely?

I've got a Carrier Weathermaker 8000 furnace that shuts off about 90 seconds or so after ignition, started doing this recently. I get flashing code "33" which indicates: The code indicates: 33 ...
3
votes
2answers
551 views

What is this name of this vent attachment next to my furnace?

What is the name of this silver vent attachment thing at the bottom of the picture? It is attached to the side of our gas furnace. The black part is an insulated air duct which goes to a vent ...