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

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4answers
474 views

Is there a special low temperature thermostat?

I have a gas ceiling mounted furnace for my garage. I want to set my garage at 35-40° F (1-4° C). Is there a special thermostat to control furnace at that low temp? (I've seen one works as low as ...
0
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0answers
40 views

How to Calibrate a Make-Up-Air Controller?

My home is equipped with a make-up air line intended to bring some outside air to mix it with indoors air prior conditioning by the furnace. I am not sure why this is necessary but my question is ...
1
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1answer
406 views

Can I convert a window A/C unit in to a pool-water cooled system?

I have an 18,000 BTU A/C unit that blew a compressor last year. Perfect for a small project. I however could not find a professional to help me out, so maybe it's DIYable. I know just about enough ...
6
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1answer
241 views

Orange flame on all appliances

I have an orange flame in all my gas appliances (gas furnace, gas water heater, and gas stove) and cannot seem to determine the cause. Background So far, I have had the gas company come out. I had ...
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1answer
53 views

Bathroom, dryer and central vac - Can any of the exhausts be combined, and can any use the same penetration?

I have these three units within 5 feet of eachother. The place where the bathroom vents to is the only place within reach to have a penetration to outside. My options are to stack these three ...
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1answer
267 views

Thermostat C-wire replacement using a wall socket?

I have a Filtrete 3M WiFi thermostat. As expected, it takes a C wire, which my apartment doesn't have and the apartment maintenance folks wont' let met wire either. However, there's a wall socket ...
2
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1answer
112 views

Breaker box or heat pump problem?

We ran our forced air heat pump today. 15 min. in we noticed it just stopped running. Looking in the breaker panel I could see that the breaker for the heating unit had tripped. When I tried to ...
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0answers
145 views

Why would said gas furnace keep shutting off?

Seems that I have a gas furnace that is having some sort of heat/air sensing issue. Basically it shuts off after running for a minute or two. But if I remove the top plate of the furnace itself it ...
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4answers
2k views

Can I modify the vent from my high efficiency furnace to prevent possible damage to the exterior of my home?

is my high efficiency furnace vent installed properly? I'm based in Toronto, Canada. In some recent cold winter weather, the exhaust is causing a lot of ice buildup on the surrounding brick. To my ...
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3answers
207 views

Should I leave the fan switch on my thermostat set to fan rather than auto?

I purchased a new Amanda Furnace in Oct'2013. I am told in order to maximize a warm, consistent room temperature I should set the thermostat to the Fan position rather than the Auto position. Does ...
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2answers
858 views

Is voltage too high in C wire going to thermostat?

I've managed to add a C wire to my thermostat. I then decided to check the voltage between the R and C wires, and find that it read as 27.8 volts, not the 24 volts it was supposed to be. Could this ...
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1answer
88 views

When should HVAC returns be opened and closed?

My Pennsylvania house was built in the early 90s, has central heat (natural gas) and central A/C, and most rooms have pairs of closable air returns on the wall near the floor and ceiling. I've been ...
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1answer
16 views

Why isn't my aircon blowing cold air?

I have 2 x 9000Btu split aircon installed in my house three days ago. In fan mode it works properly but when I switch to cooling mode the upper pipe from the outside unit freezes immediately, not cold ...
2
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2answers
305 views

Air conditioner not blowing cold air

My HVAC system had a problem during the winter where the blower motor stopped working. I got a HVAC tech to come out and replace it. However, now that it's hot again, the cooling system is still ...
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1answer
494 views

How can I figure out why the low voltage furnace fuse blows on heat but not cool?

I have a Tempstar Model NTC6100KFG1 gas furnace. Furnace was working fine through the summer blowing the AC. It's been off for a month or two as we've been changing seasons here. When I went to turn ...
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1answer
322 views

How do I connect a WiFi thermostat to my furnace's primary control?

I would like to install a Honeywell WiFi controlled thermostat to connect to a Honeywell R7184U primary control. My question concerns the "C" wire. The R7184 has the terminals labeled 1, 2, 3 and 4 ...
3
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1answer
118 views

180º/gooseneck/u-shaped cold air return?

I am in the planning stages of moving a cold air return from an inconvenient spot in the floor to a nearby wall. The basic plan is to open up the wall on both sides (cutting one stud and framing in a ...
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3answers
499 views

How can I cut a cinder block wall to run large round duct through it?

When an addition was put onto the house that I own, the previous owner just ran the duct work into the crawl space through an old basement window. I want to re-route the duct work by actually cutting ...
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1answer
61 views

What is this fabric tape made out of?

Any ideas what is this fabric tape on my cool air return ductwork? High res close-up Some of it is separating or worse falling off of the duct work on the cool air return to my forced-air gas ...
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1answer
54 views

Propane HVAC system - convert to use wood burning stove?

is it possible to remove the propane part of the HVAC and replace it with a wood burning stove? If so what would I have to change - eg the chimney etc etc?
0
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0answers
33 views

How do I fix a blower fan snap disc that opens too soon?

My fan limit thermodisc opens too soon and shuts the fan motor down after the gas burners ignite and runs for about 2 minutes. I replaced the limit switch and still have the same problem. How do I ...
0
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1answer
63 views

I just had a heat pump installed. I had central air already so the duct work was there already for a/c. Should my vents in the ceiling be changed?

One person told me I need to change my Registers on the first floor that are in the ceiling because the house was set up for air not heat. They say the Registers I have keep the cold air going a ...
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3answers
1k views

How effective is a heat pump for AC and a heat pump/furnace for heating in New England?

We currently have a central AC unit and oil furnace. The AC is broken and the furnace is old, so we are thinking of replacing both sometime in the next year. We are considering replacing the AC with ...
2
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2answers
198 views

Furnace flashing 4 times (Ducane)

My Ducane furnace flashes 4 times, runs for 5 minutes, and then the burner goes off. When the limit switch is jumped it runs good. What needs to be changed here?
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3answers
201 views

extra thermostat, electric dampers and 1 furnace [duplicate]

I have a problem similar to others that have posted: balancing heating/cooling throughout the house. I have already played with adjusting the vent's air flow as well as the manual dampers in the ...
0
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1answer
194 views

can i use an inline exhaust to vent a kitchen and bathroom?

I have 2 bathrooms and a kitchen that are currently unvented. I would like to install an inline exhaust fan to service all three. I will be putting the exhaust fan just inside a gable that will have ...
0
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2answers
2k views

How do I connect the common wire in a Carrier air handler?

I am trying to install a new wifi thermostat in my home and need to locate the common terminal for my air handler. I have a Carrier model FB4CNF030. It's a new construction home and I have the blue ...
12
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6answers
573 views

Is it worthwhile to have ductwork cleaned?

Was rearranging some ductwork in my basement, and noticed that the stuff I took down was pretty filthy inside (especially the return air ducts). Is it worthwhile to have ductwork cleaned out? What ...
4
votes
1answer
145 views

How can I determine if my HVAC system has features which are not currently wired to my thermostat?

I recently upgraded to a Nest Thermostat. This new thermostat supports many more terminals and features than my previous thermostat. My old thermostat had the basic terminals; G,R,C,Y, and W. I am ...
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3answers
73 views

can I install a new thermostat by just turning off the power instead of turining off the circuit breaker?

Can I install a new thermostat by just turning the power off at the servicemen's switch, instead of at the breaker?
1
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2answers
323 views

Controlling separate heat and AC devices from a single thermostat

I have hydronic radiator heat powered by a gas furnace situated in one mechanical room of my house and a currently being installed central AC whose air handler is situated in another mechanical room ...
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2answers
1k views

Can a boiler water feed / pressure relief valve be repaired?

I am a homeowner trying to troubleshoot my hot water boiler system (Winkler Gas Boiler). I noticed recently that my boiler is reading zero pressure. The combination fill & pressure relief valve ...
2
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1answer
861 views

Is it normal for A/C performance to improve when vent covers are removed?

I recently moved my office to the second floor of our home and I haven't been able to get the temperature below about 78 even though the thermostat is on 72. My son's bedroom had been the same way ...
2
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2answers
718 views

Recommended proximity of HVAC vent to return air

I have an upstairs room with an HVAC vent in the ceiling above the door. The return air is in the hallway just outside of the same door. This room also happens to be the hottest room in the house (by ...
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2answers
189 views

HVAC air handler with a built-in humidifier

I am in the process of choosing an air handler to use only for AC. I plan to keep radiant heat. However, in the winter, I would like to use the AC system to blow humidified air to compensate for the ...
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2answers
304 views

Why doesn't my gas furnace ignite?

I had a Lennox slp98dfv installed last year - it has a surelight ignition - it now just blows cold air - so I assume the pilot light is out - but not sure how to light it - as u cannot manually ignite ...
3
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1answer
567 views

Why would my Goodman gas furnace start but not stay on for more than 2-3 minutes?

I've got a problem with my 15 year old Goodman furnace. It starts w/o problem, inductor begins working, hot surface ignitor lights up and ignites the gas. Then the main blower starts working and the ...
2
votes
2answers
83 views

How to measure air flow coming out of registers?

As my contractors finish installing ductwork and the air handler for my central AC system, I would like to have a measure of how many CFMs come out of each register, as a function of how the system is ...
0
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1answer
230 views

Can I use a heat gun to melt the Ice from the external part of split ductless system?

I've got a Mitsubishi Mr. Slim split ductless system in the "mother-in-law" suite of my house. There are 3 wall units connected to it, one in the front room, one in the bedroom, and one in the ...
2
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3answers
1k views

Does a whole house humidifier go on the intake or outlet of the furnace?

On what side of the furnace do I install the tank of the humidifier (the warm side or the return air side)?
0
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1answer
49 views

Is it OK that my AC is making squeaking and rattling noises?

Just want to get some initial thoughts before the repairman comes. I have a 3 year old 2.5 ton Goodman AC unit. I set the temperature to 74°F last night (AC) and woke up to a nice and chilly ...
34
votes
4answers
99k views

How can I add a “C” wire to my thermostat?

So, the spiffy new wi-fi thermostats want power on the C wire from thermostat, but the old thermostat doesn't have a C wire at it. What's the easiest way to add the C wire/24 volt to the thermostat ...
0
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1answer
71 views

I have both a natural gas burner with baseboard heat and 6 Mitsubishi Mr. Slim units. Which would be less expensive to use for heating my house?

I just purchased my house a few months ago. The house has both a 2 zone natural gas burner with baseboards for heat and 6 Mitsubishi Mr. Slim units that I can use for either A/C or heat. I am not sure ...
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1answer
1k views

Why is my furnace blowing hot air outside through a PVC pipe?

I turned on my furnace and went outside and noticed hot air blowing out a J-shaped PVC pipe. Is it a vent or error that needs to be plugged?
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0answers
117 views

How do i connect the common c wire in a carrier air handler?

I need help in determining where to hook up the common c wire for my new thermostat. The carrier air handler appears to be a little more complicated than others.
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0answers
55 views

Spiral pipe size vs. CFM for AC

My AC contractor just brought some 8 and some 6 inch spiral pipe to install tomorrow. I do not trust him nor do I trust a single contractor out there, hence posting here to confirm. I am getting a 3 ...
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1answer
63 views

How can we protect this furnace from environmental conditions?

I was recently asked to look over the utility closet of a friend, and several things I saw looked very concerning, from an energy-efficiency standpoint. This closet is approximate 3' x 6', and is in ...
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1answer
31 views

Testing AC ductwork

I am about to bring in a contractor to install central AC in my house. I am in the final stage of a rather comprehensive remodeling effort, all of which was done either by me directly (cca. 85%) or ...
3
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4answers
3k views

Why would a furnace overheat with a standard density filter?

Some time ago I found my furnace (gas, forced air, downdraft) was getting stuck on, blowing cold air. I could reset it, but it would happen again after a while. After calling out a service man, I ...
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1answer
100 views

Legal requirements regarding 100% asbestos duct work [closed]

I am renting a condo. After starting the heater, dusty air came out of the registers, so I called out a company to clean the ducts. They verified the ducts are 100% asbestos and cannot be cleaned. ...