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

learn more… | top users | synonyms

0
votes
3answers
248 views

Do I need a neutral wire when connecting a 240V device?

So this is still not very clear to me: I am trying to get 240V to an appliance that does not need a plug (direct wiring), I won't need a neutral wire, is this right? In fact there is nowhere to ...
0
votes
1answer
523 views

air conditioning system stays on even when we turn off our thermostat

Our A/C system stays on even when we turn off our thermostat. What should we do to try to fix it?
0
votes
3answers
149 views

Will high efficiency furnace plumbing lead to cold air entering the house?

At the outside wall of my house I can see two white PVC round tubes/pipes, I understand one is for sucking air from outside, and one is for furnace blowing warm air to outside - correct? We are ...
0
votes
2answers
278 views

how do I keep leaves and foreign objects out of the top of my a/c unit?

Is it possible to make a lid that is light enough for the air coming off the fan to raise it attached with hinges so it drops back down when not in use. This would keep debris from getting inside, yet ...
0
votes
1answer
535 views

What type of dryer best handles long exhaust vents?

I have a very long exhaust line (about 5 meters) from the dryer and have issues with moisture staying in it when I do laundry. Since the old dryer broke down, I am now shopping around for a new dryer ...
0
votes
1answer
522 views

Exhaust venting into air return?

In the condo (2 story semi-detached townhouse built in 2004) I rent, the main bathroom has an interesting vent system. When turned on, 2 fans are activated. One is a booster of some type and ...
0
votes
1answer
476 views

Why do I have a large PVC pipe venting warm air outside intermittently?

There is a large PVC pipe (3 actually) which vent air intermittently. I started noticing I could see steam rising over my deck in the morning and then I found that these pipes vent air at least a ...
0
votes
2answers
30 views

How do RH/RC/R and Y/W relate for HVAC?

I have the following notes for HVAC (that I've compiled from reading through here): Thermostat wiring: C low voltage power wire that brings power from heating/cooling equipment to thermostat ...
0
votes
1answer
32 views

Does thermostat need to be grounded?

If a thermostat is connected to an air handler, which is connected to the main panel and has a ground wire, should one of the thermostat wires be connected to the ground?
0
votes
2answers
38 views

Is there a way to measure the output of a single HVAC vent?

As inspired by this previous question, is there a method or device used to measure the output of a single HVAC vent or the output of a single room? I'm imagining some sort of hood device that could ...
0
votes
2answers
128 views

How does fresh air get inside a house with central heating other than through cracks of door or window on a cold winter day

I'm not sure how fresh air, or oxygen, gets inside my house other than through cracks of window or door on a cold winter day when the central heating system is on. I have a pipe that is coming from ...
0
votes
1answer
48 views

Pilot lights, but main burners don't on furnace with no flame sensor

I have a Rheem furnace in my house. It recently stopped working. It is the type where the pilot is not always on. Anyways, the ignition will kick in, and the pilot lights just fine. However, the ...
0
votes
1answer
102 views

Air Conditioning Drain Pump

I am going to purchase Multi-Split air conditioning unit for my apartment that I am fully renovating at the moment. So it is the right time to make wholes in the walls etc. The supplier is giving an ...
0
votes
1answer
118 views

What is the rated power of American central air-conditioning control circuit?

I want to know what is the rated power that American central air-conditioning 24V control circuit can supply, which is also the power supply for Nest. Nest gets its power from the 24V control ...
0
votes
1answer
49 views

Does cold galvanizing compound restore the rust protection of a galvanized duct?

The house is a ranch built on slab on grade with a newer furnace in a downflow configuration with A/C. The in-floor clay tile supply lines are in good shape and clean. The original 60 year old ...
0
votes
2answers
631 views

How do I cut a straight line in an installed wood floor for a flush mount HVAC vent?

At some point a previous owner installed hardwood flooring in my house. Nice. They did not however make a hole for the front entryway heating vent. The duct and duct outlet exists in the crawlspace ...
0
votes
1answer
80 views

Can the back side of a window type aircon exhaust in an empty ceiling area?

I'm planning use a window type A/C on my little attic room. My A/C unit is just .5 HP, just enough for the small room. The problem is there's no proper exhaust area like the standard Window type. ...
0
votes
1answer
35 views

Are there testers for thermostats?

One of my A/C units was struggling to keep the temp. down to 85 three weeks ago. The pipe outside was slightly frosted so I already knew the unit was a little low of refrigerant. Called repair company ...
0
votes
2answers
59 views

HVAC breaker issue

My HVAC (Tempstar 5300XL) comes on automatically at the preset temperature. It may run cold for 45 minutes to an hour, then trips the breaker. What is the most logical problem, and solution?
0
votes
2answers
84 views

2 PVC Pipes running from unit to basement

I have two 2" PVC pipes running from outside (AC unit) to the inside set up (furnace?). I need to cut these pipes and re run them since they are blocking the water heater which I need to take out. I ...
0
votes
1answer
71 views

Should I add a return or another supply to a large room with only one supply?

I just moved into a new house and I have that one room that always seems to be hot. It's on the 2nd floor of the house with the attic over it. The other 2 rooms on the 2nd floor are always a nice ...
0
votes
1answer
92 views

Is my AC right-sized for my house

2 years ago I had a Bryant 2 Ton 13 Seer Air Conditioner + new furnace and coils installed in my 2800 sqft ranch style house with 6 bedrooms and 2 baths split evenly between the basement and main ...
0
votes
2answers
224 views

Can I remove a furnace compartment vent that's obstructing roof repair?

There are two vents going up to our roof, one is the normal vent from the furnace exhaust straight up to the roof. But right next to it there's a second vent pipe, a little larger and single wall. ...
0
votes
2answers
115 views

HVAC system setup

I have a builder building me a home right now and we had agreed to set up two separate heating and cooling systems for the first floor and second floor of the house. I raised the issue the other day ...
0
votes
1answer
4k views

How do I connect my whole house humidifier to my furnace?

Connecting Desert spring Humidifier to the furnace: Do I eliminate the 24V transformer that came with it? The furnace Keeprite has the the electronic board says Humidifier W1 and C. where can I ...
0
votes
1answer
88 views

Adding outside wood boiler to oil furnace

I am adding an outdoor wood burner (water stove) to my home. Water to air heat exchanger plumbed into existing ductwork for oil burner. What are my options for running the oil burner's fan WITHOUT ...
0
votes
2answers
550 views

Can I move second-floor duct-work from the floor to the attic

I have a two story home that sits on a slab. There is some duct work that runs through the slab. I have some duct work that runs through the ceilings of the first-floor and points towards the floor of ...
0
votes
3answers
1k views

A/C Runs non-stop and shuts down without reaching desired temp

I have had a repair man out 4 times and he says he can't find anything wrong with the unit. I cannot even feel air coming out of the diffusers unless I climb on a chair and put my hand right next to ...
0
votes
3answers
58 views

Can forced central air be retrofitted with central humdifier?

Several homes I'm considering have central air conditioners, but radiators or baseboard heaters. Is it possible to use the A/C ductwork to provide humidity to the home? I assume most central ...
0
votes
1answer
258 views

How can I prevent my furnace exhaust pipe from freezing?

My furnace keeps on turning off because my air intake freezes. The reason it freezes up is because my neighbors exhaust vent blows directly on it. What can I do to prevent this?
0
votes
1answer
46 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 ...
0
votes
4answers
6k views

How can I modify a 4 wire thermostat to a new thermostat requiring c wire?

I attempted to replace my thermostat with a fancy new Trane z-wave enabled model. To my dismay my home was only wired with a 4 wire setup with no 5 hidden in the bundle. I followed Insx on the web ...
0
votes
1answer
494 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 ...
0
votes
1answer
10k views

Wireless Thermostat C-Wire Substitute

I've read How can I add a "C" wire to my thermostat? and checked out the Venstar Add-A-Wire Accessory. I've watched Honeywell's YouTube video on "DIY Wi-Fi Thermostat Substitute G-Wire for C-Wire," ...
0
votes
1answer
992 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 ...
0
votes
2answers
1k 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 ...
0
votes
1answer
171 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. ...
0
votes
2answers
311 views

AC won't turn on after replacing thermostat batteries

we replaced the batteries on our thermostat after they began flashing for a few minutes. We'd been using the heater up to that point. After replacing the batteries, the heater does not turn on ...
0
votes
2answers
8k 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 ...
0
votes
1answer
498 views

How can I get my thermostat C wire connected? [duplicate]

I have an older furnace, on the switch block I have Y,C.W,R and an unlabeled screw that connects to the shut off it looks like. I need to hook up a thermostat that needs the C wire. I have a spare ...
0
votes
1answer
41 views

Does it take long time to turn AC unit around?

I am wondering if it can take a full day of work to turn around AC unit like in this post . Must my new air conditioning unit be 3 feet from the wall (or positioned backward)?
0
votes
2answers
16 views

can I use AC top cover for Trane XR16

My contractor installed this system yesterday, at my property: "Trane T4TTR6060C1000A RX16 5 TON XR16 A/C 16 SEER rating R410A". ...
0
votes
1answer
22 views

Are foam filters in return important?

I recently got all my hvac replaced, and in the returns were these black foam filters. Unfortunately, the drywallers sprayed texture all over them. I didn't have these in my old returns, but it still ...
0
votes
1answer
30 views

Why doesn't the extra C wire work when hooking up WiFi thermostat?

My existing thermostat has an extra 5th wire. It's blue. We used that as the C wire. We have forced hot air so we checked the furnace and it has all the wires hooked into a clip that plugs in. It has ...
0
votes
1answer
22 views

how to measure CFM in digital animometer [closed]

dear friends how to measure CFM in digital anemometer and tell how its calculated in both practical and theoretical
0
votes
2answers
70 views

Bedroom 10 degrees colder than rest of floor!

I'm at my wits end. I just moved into a new (for me) 2 story house (1998) that has some weird heating issues. The house is about 3200 sqft the upstairs is heated by a furnace located in the attic. its ...
0
votes
1answer
35 views

Why does my nat gas furnace pilot light stay lit at normat temp setting, but goes out when I bump the temp up a couple degrees?

Recently the gas company replaced our meter and thermocouple. After they left, the pilot light kept going out randomly. 4 techs came over a 3 day period and could not diagnose except to reassure ...
0
votes
1answer
23 views

Payne/Carrier furnace pilot problem

The furnace blower started running constantly and I noticed there was cold air coming fromm the vents and not heat. I have a Payne (Carrier) furnace. The spark gap igniter was not throwing a spark ...
0
votes
1answer
38 views

Replacement part for coal stove blower rheostat

I have an Alaskan coal stove and my blower rheostat broke this morning. I opened it up hoping to be able to fix the part instead of buying a whole new fan controller. Any motor controllers that I ...
0
votes
1answer
24 views

Is ice on ERV door normal?

My ERV is forming ice and condensation on the top of the door and on top of the unit (presumably because the fresh air intake is on that side). The outside tempersture hit about 1 degree F today. ...