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Questions tagged [hvac]

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

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1answer
155 views

Adding common wires for nest thermostats

I recently installed some Nest E thermostats for heating only usage. They’ve been great so far, but my HVAC guy warned me I would likely run into issues without a common wire. In the newer part of the ...
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0answers
23 views

Furnace won't light when fan commanded on

House and furnace are 5 years old. Furnace is an Allied A95UH2V090C16S-07 and is interlocked to a Lifebreath HRV. Functioned fine up until a couple days ago. My wife calls me and tells me that ...
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3answers
80 views

Do HVAC technicians need to be registered or licensed? [closed]

We had several HVAC companies come out on a Sunday to look at our furnace. Unfortunately, it could not be fixed. Each contractor offered their solution and did not charge us for their time- but if ...
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0answers
122 views

Do I need a sealant between inducer motor and flue transition on furnace?

I just replaced my inducer motor for my furnace, and have noticed there is hot gas that leaks between the flue transition and inducer motor. I can't remember what it did before the switch, but it ...
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1answer
52 views

How should I repair a soot-covered cad cell on my oil furnace?

Earlier I posted about my furnace not staying on. I had my question answered fully, but seeing as it just snowed about 18 inches here I'm not in the position to call anyone to diagnose, so I decided ...
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1answer
57 views

Does insulating an Air Conditioner from inside (for winter) increase chance of damage?

I have two window air conditioners that I'd like to seal during winter (Friedrichs). I'm considering sealing them from inside (with blankets or foam) as they let in a lot of cold air and noise. ...
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1answer
35 views

New primary control switch problems

About a week ago , I had someone to come in and replace my old RA116 stack switch with a Honeywell R8184G oil primary , for the first day it was fine, next thing I know the furnace turned off and ...
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1answer
37 views

Heating Split level

I'm surprised that I can't find more useful information on this. I have a split level home. Main floor contains living dining and kitchen. 8 stairs up to top level with 3 bedrooms and a bathroom. ...
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0answers
34 views

thermostat does not accept C wire connected to AC unit

I have three identical thermostats, model Radio Thermostat CT101. Two of them have C wires connected to the burner and work fine. The third one controls a heating zone and also central AC. It has R ...
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1answer
45 views

Why is my Heat Pump fan not turning in cold weather?

My heat comes on and you can hear the condenser unit come on as well. However the fan is not turning? The outside temp is 30 degrees? Is this normal? Can anyone share some wisdom on this? Thank ...
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0answers
29 views

CAR duct in same bay as electrical wire

I'm going to install a cold air return (CAR) duct through an interior wall that has some electrical running through it. The CAR duct will run vertically, but near the bottom third of the bay there is ...
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3answers
61 views

Can I connect my two HVAC systems?

My house has two HVAC systems. One is in the attic and has supply and returns in the ceiling of the second floor. The other is in the basement with supply and returns at the floor of the first floor. ...
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0answers
14 views

Can I place the MUA vent directly beneath the range?

In California, I'd like to upgrade my range hood and may require make up air. I've seen these installed in the toe kicks of kitchen cabinets. Would it be acceptable to install registers directly ...
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1answer
87 views

How do you increase humidity with HRV system?

I’m wondering how to increase the humidity in my home. I have a venmar constructo HRV system and have looked at the manual and many videos and can’t find the answer. I’d like my humidity to be 35% for ...
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0answers
26 views

Heating zone only partially working for gas boiler

I did all of these things: Checked the pressure and temperature, which looked OK Attempted to "purge" the area. The zone (let's call it Zone 2), was purged by opening the valve on the return. I had ...
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1answer
140 views

Can I remove the top plate at top of an interior NLB wall?

Is it safe to remove the top plate in one section of an interior non-load bearing wall between two studs space 16" apart? The reason I ask is because I need to run some ductwork to my cold air return ...
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0answers
43 views

No 24VAC between R and C on Rudd R801 Control Board

I’m replacing a older programmable thermostat with Ecobee 4 which is to control a Ruud R801 HVAC unit installed last year. I have access at the thermostat to a wire (orange) that goes to the C ...
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2answers
97 views

What would cause a musty smell from my portable A/C unit?

Even when the compressor is not running in cooling mode and just the fan is spinning it is producing a musty smell. Where could the smell be coming from and how can I clean it? This unit does not have ...
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2answers
1k views

Test voltage for common on HVAC wiring

I'm working on adding a smart thermostat, and as many older setups have it, my current thermostat doesn't have a 'C' wire. However, if I pull the wires further out from the wall, the feed from my A/C ...
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1answer
39 views

HVAC experts - what do you think about my coils? Furnace showing more than 144 degrees

I have two furnaces - one for each floor. One of the furnaces that were replaced within a year keeps blowing cold air randomly. I would reset it by turning the main power switch off/on and then it ...
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1answer
41 views

burners out of sequence with blower motor

I have a Bryant furnace plus 90 model #398AAW036060D. I just changed the blower motor. In the last five years I've changed the main board, inducer board, pressure switch, and cleaned the igniter the ...
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1answer
50 views

Can i install condenser unit of split air conditioner in a rotated position?

I have to install a 1.5 ton split AC in my home. Due to some space constraints I can't install the condenser unit (the external unit) as instructed. Can I install it by rotating it by 90 degrees. I ...
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1answer
31 views

C wire in wireless Thermostat Transofrmer question

I have a rheem handler with a 46-23115-02 transformer. I do not have a C-wire connection that I can see. I have a 5 wire cable... so I do have a blue wire available that I can connect as the common ...
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1answer
171 views

No C Wire Terminal on Furnace

I am trying to install a new smart thermostat that requires a C connection. The previous thermostat used a 4 wire connection but there is a blue wire that's unused right behind the current thermostat. ...
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1answer
46 views

Heat pump always turns on with fan!

If I turn my fan on on my thermostats the heat pump turns on with heat or cool setting There is a jumper wired from green to w1(the heat pump) If I move the jumper to r (24v) and g and turn on the ...
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1answer
615 views

2 wires on C comm at furnace

I am trying to add a nest thermostat. But their support desk is not able to answer a simple question properly and keep asking me to buy a nest pro service. Right now my nest is connected without a c ...
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1answer
33 views

How to minimize ceiling “backwash” of air circulation in an attic HVAC system

I'm remodeling and placing a new HVAC unit in the attic. The dining room is central on the house, adjoined by the living room, kitchen, service bathroom, and (directly or via a hall) all three ...
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2answers
41 views

Using a Radiator Space Heater to Support HVAC system

I'm looking for ways to heat my home up more efficiently. I live in a 1200 sqft home that sits on the first floor and partially in the ground. So, it gets pretty cold. I was thinking of getting a ...
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0answers
45 views

Honeywell Thermostat to Nest E Dehumidification

I am trying to replace my Honeywell Prestige IAQ thermostats. I noticed that my downstairs thermostat has a dehumidification option (upstairs shows no such option). I checked the wiring at the ...
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1answer
21 views

HVAC blower control in several rooms

At my church we have lots of HVAC systems. Some of the systems condition several rooms. As you know, you can't make everyone happy at one time. The thin older ladies in one room are freezing and the ...
2
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1answer
27 views

Strange noise from heat pump

Does anyone have any idea what this strange noise is in the linked video? It happens after the heater has been on for a while, and it always seems to happen twice (a few seconds apart). https://www....
2
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1answer
165 views

Ecobee Smart Thermostat- Using Room Sensor as primary control

This is ultimately a fairly simple question about the Ecobee3 thermostat and the wireless room sensor functionality, but I'll explain my situation first. Twin home, 2 stories + finished below grade ...
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3answers
2k views

Is it bad to close furnace dampers in order to balance temperatures seasonally?

I have a two story home. As such, it's always hotter on the second floor than the first floor. As advised by many articles and how-to videos out there, I usually close the dampers in the ducts ...
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1answer
883 views

How do I configure my duct dampers for summer and winter?

My levers on my duct work for my furnace are not marked with a "WINTER", "SUMMER" How do I know which way it opened and closed?
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1answer
522 views

Dripping sound emanating from interior wall space

I've seen some other questions about dripping sounds but wasn't sure if my situation fills the same circumstances or not. I have a 2-story home and only a partial understanding of where the ...
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2answers
39 views

Multiple boilers, one expansion tank and fill mechanism?

For a building with two boilers serving separate apartments, I'd like to simplify my design by having only one auto-fill and backflow preventer, and only one expansion tank. These are combi boilers ...
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1answer
34 views

Whole House Humidifiers for Ductless Furnaces?

Is there a whole house humidifier that I can attach on my furnace that requires no ductwork? All we have for ductwork, is a galvanized pipe that sits on top of my furnace. There's a blower that blows ...
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1answer
56 views

HVAC one unit Residential system dual zone forced air

Have a Residential system. One unit, dual zone forced air HVAC. 2 thermostats. Is this type of unit designed to run the heat downstairs, while running the AC upstairs at the same time? The house/...
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1answer
66 views

Furnace getting power, but heat/AC not kicking on. LED on board is not lighting up. Thinking the transformer is gone

So far I've been successful in maintaining and repairing my own HVAC system in my house. First week we bought the house (we knew going into the purchase) I replaced the main board. It's been golden ...
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1answer
31 views

Is this circuit correct for controlling old 750mv HVAC with NEST

I am just starting out with wiring and some other home improvements. Decided to install a Nest 3rd generation thermostat. I had a TH5110D Honeywell thermostat, so I pulled it out and found 5 wires ...
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0answers
11 views

Boiler not modulating when using DHW

My combi boiler when I'm using DHW is behaving on/off (making annoying fluctuations in DHW temperature) but modulates when I run my heating system. What's wrong with it? My boiler is a Hermann (now ...
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1answer
116 views

Connect C wire to Furnace

I have a Lenox Merit system in the house. I am trying to install Nest E thermostats and want to do it with a C wire. I noticed an unused Blue Wire (pic attached) at the thermostat location and then in ...
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2answers
120 views

Is my whole-house humidifier installed and working as expected?

I have a Honeywell whole house humidifier model HE240. Its installed on the warm air supply. I thought this would put the humid air into the warm air stream. Instead its blowing air to the cold air ...
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2answers
359 views

How can I fix this furnace filter slot to prevent filters bending?

I noticed a problem with my furnace filter. In the vertical slot where it gets installed, there is a channel along the bottom but not along the top. As a result, the top corner of the filter ...
2
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2answers
80 views

How do I connect a high intensity infrared heater and thermostat?

enter image description hereHarper gave me a great answer on how to connect my Lambert high intensity heater to a thermostat in general but I have a follow up question and don’t know how to attach ...
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1answer
77 views

Can’t turn off power to thermostat

I’m installing a nest thermostat and trying to turn off power to the thermostat before doing so. I’m using a voltage tester and can see the wires coming in have power. I have two systems, one for ...
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1answer
40 views

Running two LP heaters

recently ripped out the old oil furnace that was proving to be more trouble than its worth to fix ; and went and got a 30K BTU heater, BUT its only warming up one side of the house, I plan on getting ...
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1answer
150 views

How do I install a high intensity infrared heater and thermostat

I picked up an old Lambert L-40 high intensity infrared gas heater but it didn’t have a thermostat. I can’t find any info about this heater online and I am hoping someone on here can help. I ...
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1answer
522 views

Does a heat pump create condensate during winter?

I have a large unit attic mounted. The ac drain line produces a lot of water during the hot humid summer. The water gets on top of a concrete walkway. I’m concerned that if condensate is produced ...
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1answer
65 views

How long should electric furnace element last

I've been having elements go out in my electric furnace every year. Along with that, there's generally a burnt wire or two. Every about 2-3 years a sequencer goes out. Is this normal? I've been using ...