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

learn more… | top users | synonyms

1
vote
2answers
3k views

What to do about different rooms in the house being a completely different temperature?

I moved into a 30 year old home last December. There is a problem with the HVAC. I have included a very crude drawing of the floor plan The problem is that I can't maintain a comfortable ...
2
votes
0answers
13 views

Why would my boiler expel steam when it's set at 180F

So, I have recently had some issues with my boiler system. After hiring some guys to stop by and take a look at it, they told me that the boiler pressure reducing valve, pressure relief valve (stuck ...
1
vote
1answer
44 views

Is my HVAC system unbalanced?

I bought a home back in August and the previous owner had a new 3-ton HVAC system installed. Basically right now the HVAC is located in the upstairs hallway, and the way the duct is set up is there ...
1
vote
1answer
40 views

Adding a C/Common wire to HVAC system

So I'm looking for some help in identifying where I can attach a C/Common Wire to my HVAC system, but unfortunately my system doesn't have a control board that I can easily attach a powerkit to. For ...
0
votes
1answer
546 views

Can I have a separate thermostat for a wood boiler?

I want to wire a separate thermostat for my outdoor wood boiler so that just the furnace fan will come on without the propane kicking on. This is a Coleman furnace. Is this possible and if so, how ...
2
votes
1answer
4k views

Does a compressor with a short to ground really require a complete system replacement?

My 24 year old home A\C went out some time Sunday morning. I had a tech come out and look at it, and was told that the compressor is shorted to ground, and that this means I have to replace the entire ...
3
votes
5answers
102 views

How can I vent a portable air conditioner when there's no window?

My shop does not have central air and does not have operable windows. There is a steel door in the back and cinderblock walls. My landlord is against me cutting a venting hole in either the steel ...
1
vote
3answers
115 views

Transfer Grille Baffle

I just finished building a new home and as part of the Energy Star rating transfer grilles were installed above each of the bedroom doors to allow air exchange when the doors are closed. The problem ...
1
vote
0answers
15 views

Home A/C Slow to Start

When I turn my AC thermostat to cool, I can hear it click but the outside unit does not start and no air blows inside. Several hours later everything turns on and it works fine. If it turns off, ...
3
votes
3answers
332 views

What material is allowed for a furnace room ceiling material?

What types of material, other than drywall, are acceptable by Ohio HVAC Code for the ceiling of a small furnace room which will: Have return air ducts (only) passing through it to attic space. Butt ...
2
votes
1answer
30 views

Can I use a power gable fan and ceiling louver vents to pull cool air into my house?

I live in L.A. We only have really hot weather 5-10 days a year and it usually cools off at night (outside). I also have a large Gable vent in my attic. (recently added with addition) I would like ...
2
votes
2answers
49 views

How should I wire a Trane air handler & heat strips?

Looking for validation or correction on my understanding of requirements for wiring 5 ton Trane air handler with 20kw heat strips. Of course, I read the label and identified that there are (2) 240v ...
0
votes
2answers
165 views

How can I move hot air from a cathedral ceiling to colder bedrooms?

My main living room has a 25 foot cathedral ceiling with a ceiling fan including a staircase going to the second story bedrooms. The thermostat is situated in this space. There is space to install a ...
1
vote
1answer
21 views

Good replacement actuator?

I have 2 Belimo actuators that control dampers for A/C ducts in my house that the motor has gone bad on. I can't find much info about the model "LM24-T US" so I think it has been discontinued. I ...
1
vote
1answer
22 views

Sound proofing HVAC ducts

We have an HVAC system in our house where the duct work is all sheet metal with no insulation on the interior of the ducts as all of it is buried under inches of foam roofing insulation. Works great. ...
1
vote
2answers
57 views

How can I use a WeMo controller on a non-standard outlet?

I have an older A/C unit that uses a 6-15p plug. I want to be able to remotely control the unit with a WeMo, but it uses a 5-15r receptacle and plug. The A/C unit says its rated for 208V, and I ...
1
vote
1answer
45 views

HVAC replacement

we just recently purchased an older home- 1978 - 2200 sqft, 2 stories, 2 14x20 returns - one downstairs, one upstairs, 5 ton 10 seer system, 10yr old goodman air handler but the condensor is unkown ...
14
votes
10answers
16k views

Do thermostat-controlled, auto-adjust HVAC vents exist?

The residential forced-air HVAC systems I have seen are controlled by a single thermostat in one room. One has to manually adjust the vents in order to adjust the temperature in other rooms. Is ...
0
votes
2answers
459 views

No electricity going to thermostat

Our old thermostat is working but I want to change to a new one (nest thermostat). I have two exact HVAC unit at home. I change one it works but when I change the second one it doesn't work because ...
0
votes
2answers
1k views

Installing Honeywell WiFi Thermostat

I am trying to upgrade to a programmable thermostat. I bought the Honeywell RTH9580 with WiFi. I can get power to the new thermostat and get the fan running. However, it will not work when the fan ...
2
votes
3answers
532 views

Can I cap the air return in my unfinished basement?

I noticed today that there is a massive air return in my unfinished basement. The opening is about 2 meters from the blower, and as large in diameter as the return duct coming from the upstairs. This ...
8
votes
1answer
39k views

Why is my air conditioner tripping the circuit breaker?

Our air conditioner recently stopped blowing out cold air. When I went to check on it, I noticed that the outside unit wasn't coming on. We had had problems with ants in the contacter in the past, ...
2
votes
2answers
14 views

How can I install Air condiitoning timer

want to install a timer on split air conditoning unit to accomadate my energy plan hours, too many people change the thermostat. could another thermostat be used at the pump, controlling one of the ...
3
votes
3answers
518 views

Does my crawl space need venting

I have a crawl space under my main entrance of the house. It's about 3' tall. I added a heat duct because the floor at the entrance was always cold. So my question is do I need to vent the crawl space ...
0
votes
1answer
497 views

How can I add a C-wire to a Venstar T5800 thermostat?

I am trying to replace my existing thermostat. My old thermostat has: Rh, W (coming from the heating unit). Rc, Y, G (coming from the AC unit). On the Venstar T5800, I can map as follows: Rh+Rc ...
0
votes
1answer
890 views

why does my heat pump wiring diagram show 7 wires going to the thermostat but the thermostat only says it needs 5?

Here is a link to the wiring diagram for my heat pump. The thermostat that I am planning on buying has the following terminals C, G, Y, O/B, RC, R, Aux, E, and L. The instructions say to jump the RC ...
4
votes
2answers
747 views

ductless AC split systems?

Does anyone have the ductless split AC systems offered by Mitsubishi, etc.? Is installing them a DIY job? Can you share your comments about them, in general? Edit: Inspired by DA01 comment, I'd ...
0
votes
1answer
91 views

How can I determine what grade air filter is appropriate?

I'm trying to figure out what kind of air filter is appropriate for my house. My local home warehouse store stocks over a dozen options. The primary difference between them seems to be Microparticle ...
2
votes
0answers
38 views

Is there a wireless way to cut off the HVAC y wire from my generator transfer switch?

I recently had a Generac Synergy generator installed, which went smoothly, however there was no good way to get the Y wire from my thermostat to the transfer switch and back in order to allow the ...
1
vote
2answers
3k views

How to diagnose a broken Aprilaire humidifier (Model 600)?

I have an Aprilaire Humidifier Model 600 (or maybe 600M) mounted on my furnace. The humidifier is not turning on (i.e. letting water flow over the filter) when the furnace is on. The below images ...
4
votes
2answers
1k views

How well do whole house humidifiers work?

We are moving to an area where it gets cold and snows in the winter. We come from a desert area where it is never very cold except for the dead of winter, and where we use the heater very seldom. We ...
4
votes
1answer
56 views

Is it possible to install a whole house humidifier away from the furnace?

My building is essentially a single extremely large room. It's a 25'W x 45'L x 20' H concrete box, with an open mezzanine over the back 1/3 of the box. The HVAC system is gas-fired forced air, ...
0
votes
1answer
569 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 ...
2
votes
3answers
2k views

How “freely” should a central A/C condenser fan spin

Last year my home's central air condenser fan motor stopped working. When I noticed the house wasn't cooling down I went outside to investigate and found there was a humming sound coming from the ...
1
vote
2answers
32 views

Furnace blower motor won't turn off

I've replaced both limit switches on my Comfortmaker furnace plus the control board. Blower continues to run and the unit will still heat my home. Component changeouts did not make a difference in ...
2
votes
1answer
81 views

Is it possible to add a “C” wire to my electric heater?

I bought a Wifi Thermostat but my old thermostat did not have a Common Wire. I can't use any of the swapping the G for the C solutions because I have an electric heater. I was told by Honeywell that I ...
0
votes
2answers
142 views

Gap between 6“ dia wall thimble & 6” hvac pipe

I bought a 6" dia aluminum wall thimble to vent my 6" dia hvac steel exhaust pipe through to the outside. However, the diameter of the 6" thimble is actually 6 3/4". How do I effectively insulate the ...
5
votes
3answers
3k views

Should I be concerned about fridge/freezer airflow?

We just recently had the following counter/cabinet system put into our basement family room. After everything was done, I started to get concerned about airflow. The enclosure was built in such a ...
1
vote
1answer
42 views

Damper close to main supply vs damper close to the register end: what is the difference between the two positions?

For the air duct that feeds a room, what is the difference between installing a damper at the register end and installing a damper close to the main supply duct?
5
votes
7answers
23k views

How can I prevent my HVAC condensate drain line from freezing?

Last night, my heat (forced air) suddenly stopped. Today, a plumber figured out that my heater is 90% efficient, produces lots of condensate, and the drain line had frozen. We went outside and saw ...
7
votes
1answer
97 views

Decrease dust in an old house, forced air

My house was built in 1940. I have noticed the forced air pushes out a lot of dust. This is evident from lint collecting on the bathroom vanity below a vent. It only collects lint during Summer and ...
1
vote
1answer
85 views

Did I wire this thermostat properly?

Just want to make sure I have this correct: Have M1MB 070a BW heat/ac unit w/ a 710152B control board and a Coleman outside condensing unit. -Have a four wire thermostat. R,Y,G,W -Have 2 wires coming ...
0
votes
0answers
26 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 ...
0
votes
1answer
101 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 ...
1
vote
1answer
201 views

Why does the blower in the attic vibrate during heating when it is really cold?

We have a Carrier heat pump system in our home, and the blower is located in the attic. When it is especially cold, the blower runs on high (there are three levels: high, medium, low). During this ...
1
vote
1answer
205 views

Can I remove my vent covers without disconnecting the duct?

I have an old house with flexible duct work in the ceiling. There is mold in at least one. Can I remove the vent covers to clean or will that disconnect the duct work in the attic from the vent ...
2
votes
1answer
233 views

Why does my heat pump keep triggering the high-pressure cut-off?

Our Rheem heat-pump is on the fritz. It keeps triggering the high-pressure cut-off on the outdoor unit. We've had problems with this happening before, but only when the outside temperature got to ...
1
vote
1answer
78 views

Why would only 1/3 of my registers be blowing warm air?

I have a Coleman gas furnace in a wall space in my house which somehow shares the blower on my a/c unit on the roof because it turns on when furnace is called to start, though it does bump up after a ...
4
votes
2answers
45 views

Solution for fiberglass ducts that have collapsed in basement?

I have two furnaces in my house, one for the basement and one for the rest of the house. I noticed that while using the basement furnace this winter that no air was coming out of any of the basement ...
0
votes
1answer
517 views

Where is my common wire on the unit?

I have 2 systems in my house, my heat is gas hot water radiator heating and A/C is a separate newer system. I'm trying to figure out if I can run a C wire off air handler from the A/C system to run ...