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

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0
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4answers
13k views

How can I use a separate transformer to provide a C wire to my thermostat?

I Purchased the Honeywell WiFi Prog Thermostat to replace my Round Digital Honeywell Thermostat. I have separate Heating and Cooling (Heating is a Weil McLain Boiler for Hot water baseboard and Hot ...
18
votes
5answers
165k views

What are the pros and cons of a whole house humidifier?

In the winter, my house (~2500 sqft) becomes unbearably dry. Last winter, my wife and I used a tiny humidifier for the master bedroom to keep us from completely drying out, but since then I have been ...
0
votes
2answers
2k views

How do I calculate CFM for a structure?

This is for calculating the CFM (cubic feet per minute) of air that the blower needs to move in order to compensate the total heat loss (ventilation,infiltration,heat loss through walls, windows, etc)...
2
votes
1answer
139 views

How can i add a common “C” Wire to this old system?

I have an oil HVAC that was put in back in 1996. I sadly do not know the model of the furnace and cannot dig out any paperwork on it. Anyways, i want to go with some of the bells and whistles for a ...
3
votes
1answer
486 views

Can I connect an additional wire to HVAC system where all the terminals are full?

I'm installing a new thermostat (ecobee Smart Si) and it requires "C" wire. I checked before I bought, and saw an unused blue wire behind my current thermostat. However after connecting everything the ...
1
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0answers
152 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 ...
0
votes
1answer
362 views

Adding an on/off switch for my furnace fan

Here is my situation, I want to be able to run the blower on my furnace during the summer so that the cool basement air can be circulated thought the house. I live in an old house and the thermostat ...
4
votes
1answer
7k views

Convert line voltage heating system to use low voltage thermostats

I currently have two line voltage ceiling radiant heating systems in my condo each with their own DPST thermostat. I'd like to use low voltage thermostats such as the nest. I found this transformer/...
0
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1answer
396 views

What could be causing my gas fireplace to shut off?

I have a gas fireplace that is 4 years old, that shuts off after a couple of minutes. The pilot lights ok, then the burners turn on and work fine for about 3 minutes. After that the entire fireplace ...
1
vote
2answers
185 views

Can we capture the hot, humid air from a gas-powered clothes dryer during winter?

During winter we run a gas-powered heater and evaporative humidifier to maintain indoor air quality. Meanwhile, every day (big family!) we run a gas-powered clothes dryer which dumps hot, humid air ...
0
votes
1answer
187 views

Gable venting a bathroom fan and kitchen range hood

I am planning on venting my bathroom fan and the range hood in my kitchen out the gable end of my house in separate runs. The gable end is above a gable roof, so I am hoping for some recommendations ...
0
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2answers
611 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 ...
1
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2answers
890 views

Is a PTHP an HVAC option for a super or well insulated structure?

Is a Packaged Terminal Heat Pump a good HVAC system for a structure that is super insulated or passively insulated assuming the unit is sized and fitted to meet the needs of the structure. There is ...
1
vote
1answer
294 views

Zoned oil furnace and AC thermostat question

I recently moved into a new home and wanted to replace the old thermostats with digital Honeywell ones. From what I understand the home has a Rheem 10 Seer (1996) compressor and a Williams oil furnace ...
1
vote
1answer
32 views

will using a ventilation system with an heat exchanger give me the same quality air indoors as outdoors?

will using a ventilation system with an heat exchanger give me the same quality air indoors as outdoors? is using a proper ventilation system equivalent to having all your windows open without any ...
0
votes
1answer
519 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
2k views

Air Conditioner woes: water pooling in basement, condensation on ducts, frost on outdoor copper pipe

Can someone help diagnose what's wrong with my air conditioner? The symptoms are: the air that it is blowing is not very cold It's colder than the ambient air, but not cold enough to cool the ...
1
vote
1answer
540 views

Can I install a humidifier on a horizontal duct?

I have a Honeywell whole-house humidifier (HE360A1075). Can this be installed on the horizontal ducting here on the left? It feels like it's an aluminum box under the tape. This is both gas heat and ...
6
votes
3answers
11k views

Why is my power flickering across multiple circuits?

I woke up this morning and went downstairs to find that none of the lights would come on (lights were working fine upstairs). My first instinct was thinking that a breaker had tripped, so I went to ...
1
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0answers
35 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 ...
2
votes
2answers
3k views

At what temperature should an unoccupied house be kept at in winter?

We are moving to a new house and unfortunately we don't have our house sold yet. I was wanting a recommendation as to what temperature to keep the furnace going @. I found a good recommendation to ...
0
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0answers
121 views

What could cause the heat side of our split pack heating/air unit to stop working?

Our heat side of our split pack unit (runs on propane) come on and will runs little bit but then won't come on again. We can turn it off for a while and then it will run again. What could be the ...
0
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1answer
446 views

Which is better indirect or tankless hotwater heater

I am in the process of getting my boiler and hot water heater replaced. One company gave me a quote for a Weil McLain boiler and indirect hot water heater. Another company gave me a quote for a bosh ...
2
votes
2answers
4k views

Can you terminate more than one common on the furnace C terminal?

TL;DR: Can you terminate more than one common on the furnace C terminal? Background: I've linked a diagram of how my non-programmable thermostat is currently hooked up. I want to replace it with a ...
2
votes
1answer
471 views

What could cause the furnace blower to come on constantly and no fire in gas burner?

When thermostat is turned up on my hot air furnace, the blower immediately comes on, blowing no heat, had it checked and with some luck the burner fired after about 10 tries of switching on and off. ...
2
votes
1answer
566 views

Could a high limit switch cause the furnace blower to run continuously?

My furnace was running fine. The I noticed that the unit was blowing cold air. Checked the furnace burners and they were off. I turned off the unit on the thermostat and the blower continued to run. ...
1
vote
1answer
117 views

How do I connect a 24v air purifier to hvac?

I have a MicroPure MX4 that the previous homeowner left behind new in the box. This is a 24v unit and needs to be hardwired. My question is can I connect the two wires to the terminal where the ...
3
votes
3answers
10k 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 ...
0
votes
2answers
81 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
95 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 ...
2
votes
2answers
165 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
7k 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 ...
0
votes
1answer
216 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?
1
vote
4answers
573 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
331 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
votes
3answers
4k 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 ...
1
vote
1answer
389 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
votes
0answers
43 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 ...
1
vote
1answer
985 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
111 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
169 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. I'...
2
votes
1answer
121 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 ...
20
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1answer
20k views

Humidity Levels

What is a healthy and safe humidity level that I should try to keep my house at?
1
vote
3answers
6k 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
votes
2answers
199 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
2k 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
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1answer
462 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 ...
1
vote
1answer
225 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
656 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. ...
6
votes
6answers
43k 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 ...