Questions tagged [hvac]

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

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646 views

Is it possible to run an HVAC duct through a floor joist?

i understand that the maximum size hole I can put through a 9" floor joist is 3". But if I add a 5" booster fan would it be possible to retain proper air flow and route this duct through the joist ...
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1answer
51 views

My induction blower never stops

My induction blower never stops. It was showing a code of pressure switch but if I turned off the main power and then back on it would reset and heat normally till it was up to temp then shut off and ...
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2answers
49 views

TRANE XE70 GAS FURNACE - HSI only works once

My TRANE XE70 Gas Heater ..... HSI will glow hot once and heater works fine but then doesn't work anymore on the Thermostat cycle. I've replaced Flame Sensor and HSI Module. My White-Rodgers Control ...
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1answer
28 views

Heil gas Furnace — water in the pressure switch vacuum hose

Every few days I have to remove and drain the the rubber tube from the pressure switch to the furnace or it won't ignite. Why is water condensing in that tube? It's not a hard thing to fix-- but I ...
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1answer
96 views

How to connect c-wire to Burnham Series 2 boiler?

I am trying to install my ecobee 3 light but the previous thermostat did not use any c wire. Fortunately, there was an unused wire in the wall and I would like to set it up as a c-wire. The problem is ...
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1answer
55 views

How to improve heating/AC flow in second floor?

We moved into our house about a year ago and the second floor in my house never get enough heat in winter or cold AC in the summer. Our first floor can be a 72F deg while our upstair stays at nearly ...
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0answers
231 views

Daikin Mini Split Runs Constantly

We had a Daikin ductless system installed as a replacment for our old system that finally died. We have 4 total units inside the house, with 1 in each of the 3 upstairs bedrooms and a larger 18K BTU ...
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0answers
11 views

Oil furnace cmf280-pg convertible problems

Cmf2 80-po convertible with a auto limit switch and a manual aux limit switch. Furnace will run a heat cycle to desired temp but then blower fan runs to cool furnace in 4 very short 3 second spurts. ...
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2answers
30 views

Where should my furnace filter go in a Lennox G40UH24A045 series furnace (Merit)?

I cannot find the filter and my furnace is not providing any heat. The limit switch is working fine as is the flame sensor. Diagnostic lights are: 1 slow bling 2 on Any clues? Thanks
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1answer
65 views

Old thermostat to Hive thermostat

My wife decided we needed a smart thermostat... which means I need to install said thermostat... Currently a Bryant Evolution series is mounted. She purchased the Hive with Hub when it was on sale. ...
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0answers
15 views

how to communicate thermostat to turn on wood heat system when during heat pump defrost cycle

I have physically disconnected the strip heaters in my air handler but the fan still runs which I do not want. I have a wood boiler I want to run in place of the aux heat Can I disconnect the white ...
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1answer
59 views

How can I prevent makeup air vents from exhausting conditioned air?

The utility room has two 8-10 inch ducts running to it from the exterior of the home. There are also three fireplaces in the home, and we have noticed that occasionally the house smells like smoke, ...
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2answers
218 views

How do I install flex duct to existing duct including registers

When my home was built in 2016 the HVAC runs from the furnace in the basement up through the house uses 7" R4.2 insulated flex duct. I am in the process of finishing my basement and I would like to ...
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0answers
79 views

My furnace blower will not turn on when on when in E-heat mode with auto fan

I have an electric furnace Carrier model FB4ANF030. I enclosed the wiring diagram. Issue: The blower fan will not turn on automatically when the thermostat is set to "Emergency heat" and "Fan Auto". ...
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0answers
18 views

Hvac electric furnace Nordyne E1EH-012HA

I have a problem with Nordyne electric furnace with A/c coil above. It started the winter short cycling, then did nothing. I became a YouTube maniac trying to figure out the problem. I first replaced ...
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2answers
57 views

Tankless hot water to heat home

I have a 1200 square foot second floor apartment that is presently heated using a forced hot water radiator system. The system is called a Paloma "Paloma Pak" heating system. It is basically a ...
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0answers
46 views

Can I use an available wire as a C-wire by adding it to an unoccupied 24v terminal?

I want to add new thermostats in my home. Luckily, the wiring to my thermostat has an unused wire in the bundle for the required "C-Wire". It has R,G,Y,W, and an unused blue. The thermostat wiring ...
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1answer
43 views

Can't find HVAC C terminal

Could any of these be the c terminal on my hvac unit? There's already a c wire there, just can't figure out where to connect it.
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1answer
47 views

2 Air Filters in Air Conditioning Unit

My air conditioning system has a 2-layered (each 1") filter holder, definitely made for two filters. My idea, to improve the filter life and have the least air flow restriction, is to have the initial ...
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0answers
16 views

How to dimension air ducts for a combination heater/HRV?

I am looking at this product (version RK5) for both heat recovery ventilation and supplementary heating via warm air (seasonally). It has an extra inlet for air recirculation, which it can mix with ...
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1answer
47 views

How can I deal with a heat pump condenser producing lots of water?

Heat pumps was replaced in 2017. North Florida has had moderately cool weather (50-60 degrees F) recently. I noticed water underneath one of the units. Is the water pooling normal? If yes, why? If ...
2
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1answer
57 views

Solar panel as a hatch and Is sleeping under a solar panel safe?

I'm looking to build a very large custom roof hatch/vent on my van. I was going to make to top out of Lexan, but then I realized I might want a large solar panel on the roof as well. I was looking at ...
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27 views

Fan Blows Constantly Even With C Wire

Nest stated that my furnace only set up (we have an evap cooler) would work with their Nest E product. I self installed only two wires, R and W. The heating works; however, the fan always blows ...
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0answers
83 views

Fan only mode not turning on blower - 2 wire blower

Our manufactured home has a colman furnace and for heating it works fine. I would like to use the fan only mode when we have the fire place going but it is not hooked up, and I just want to make sure ...
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3answers
65 views

Can I upsize my air conditioner if I have a two-speed compressor?

The upper floor of my house has a split A/C, three-ton. When the temperature gets up above about 95 Fahrenheit, the unit can't keep the upstairs cool. That means that for a few weeks a year, my kids'...
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0answers
35 views

Is an alcohol-based spray cleaner ok for cleaning an aluminum AC evaporator coil?

Simple alcohols such as ethanol can, apparently, corrode aluminum. However, this corrosion reaction seems to be very slow at room temperature and below. Is an ethanol based, non-foaming spray cleaner, ...
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1answer
102 views

Zone Controller T-Stat Wiring w/ 24V transformer, isolation relays for 2 zones

I have a new Navien SmartZone+ 6-Zone Control for my boiler-based heating system. It is great, except it provides no power on C. I realize the internet has researched the heck out of adding a C ...
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1answer
55 views

Why is my steam radiator rattling like this, and what can I do about it?

I have one-pipe steam radiators in a home built in 1905 (condoized in 1998). Only one of the radiators, the largest, makes this awful rattling sound when the system heats up: https://youtu.be/...
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0answers
21 views

Coleman Wall furnace in 1967 mobile home gas model # 8670A

My old wall gas furnace blower motor keeps running and shutting off not cooling the system down and smells hot inside and outside?
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0answers
73 views

Nest thermostat installation to furnace and heat pump

We have T874G1196 thermostat by york (can only find honeywell documentation) MB7BM-1200K-B air handler H8HK015H-21 electric heater Thermopump (heating and cooling) We want to connect it to a nest ...
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0answers
20 views

Replacing Flame Sensor on Ruud Silhouette Furnace

I'm quite new when it comes to looking at furnaces. The furnace in my house recently started shutting off before getting to the temperature the thermostat is set to. Eventually we'd reset the whole ...
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2answers
6k views

Half my house losing power, HVAC the key factor

For the past couple of weeks I have been losing power occasionally to half my house. My central AC goes out, half my kitchen, living room and my kids' rooms. There are no tripped breakers though. I ...
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1answer
135 views

How to fix A0 error code of a Daikin split system air conditioner

When I tried to turn on my split system AC today, the indicator light just kept blinking and the air conditioning was not on. Here is the error code as displayed on the remote According to what I ...
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0answers
17 views

Open ceiling duct in finished basement

Moved into a new house that was only used as a summer home and had a portion of the basement finished. They tapped into existing duct work from my HVAC system to run into the finished area but bc it's ...
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3answers
54 views

How to seal joints in ductwork when tape is not an option

The duct-work in the basement for my forced air heating system has been modified at various points over its long history and as a result had quite a few leaks when I moved in recently. I used foil ...
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1answer
14 views

Draft Inducer replacement motor part number

The draft inducer motor in my Payne furnace started making a whining sound the other night, so I ordered a replacement from Ebay. My part number is HC21ZE121A, and the motor I got is missing the 'A' ...
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2answers
49 views

Is there harm in using my mini-splits in conjunction with my hot-water baseboard heat?

My new house has a natural gas boiler with three zones of radiant baseboard heat (one per floor). It also has a mini-split system (again one head per floor). The mini-split was advertised as air ...
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1answer
35 views

Carrier Furnace 58STX110-14122 fan starts the first time, but fails to start at subsequent calls for heat

On a Carrier Furnace model #58STX110-14122, when the initial call for heat comes on, everything works just fine in the following order: Thermostat sends a call for heat Draft Inducer motor kicks on ...
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0answers
31 views

AC Common wire disappears

On my furnace there is a wire that is labeled C/Common. But at my thermostat there is no common wire. Wires on furnace control panel: W - White Y - Yellow G - Green C - Common Wires at my thermostat: ...
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2answers
40 views

venting a range hood outside on our cedar cabin

i need to vent our range hood outside on our cedar cabin and it is on the front of the house we would like it to be as inconspicuous as possible I can not find a vent that would work well with a cedar ...
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0answers
66 views

Why is there a hole in return duct

There's a hole in return duct going under my house; why?
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2answers
61 views

Why is this airduct twitching and making a noise?

I have an air duct in my basement. It leads from my furnace (I think?) to the outside world. However, as you can see from this video, it is "twitching". Every second or so it jerks slightly and ...
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1answer
45 views

Bad Limit Switch?

My Nest thermostat is not working and it says the red wire is not getting power. The gas company man poked around the furnace and thinks it is a bad limit switch. Question: can a bad limit switch stop ...
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2answers
62 views

Is 4“ Ducting Used for a 4” Bath Fan?

I'm interested in installing a bath fan and am currently planning ou the project. The fan specs (https://www.homedepot.com/p/Delta-Breez-GreenBuilder-Series-100-CFM-Wall-or-Ceiling-Bathroom-Exhaust-...
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1answer
23 views

Blower turns on and off even though the unit is satisfied

My heater works fine when I set the temperature to 69 and the temperature hits the desired temp it shuts off, then about 2 mins later the blower turns on like the heater is going to start up again, ...
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4answers
151 views

Best Way to Heat a Ductless Multi-Level Home

I just bought a home and it desperately needs an update to its heating. It currently has baseboard electric resistance heaters in every room. There is no duct-work in the house. We're in cold humid ...
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0answers
40 views

HVAC indoor fan stuck buzzing

My old Sanyo SAP-KRV123EHA had a noisy ball bearing in the indoor fan unit. Since Sanyo is no longer making these units I tried replacing the fan bearing with ceramic ones. After assembling the motor, ...
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1answer
74 views

nest 2nd gen, no common wire/terminal in the fan coil unit

I'm trying to install an older nest in my condo but it immediately complains that there's no common wire attached (error e24). I opened up the fan coil in my condo and there is no specific terminal ...
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2answers
52 views

Hot water (steam?) gas boiler not engaging burners, low pressure, sight glass full

At the beginning of the winter season my boiler wasn't turning on, but I got it to work by turning on the inlet valve and just letting it feed water until the gas burners kicked in. The sight glass ...
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1answer
77 views

What powers a Nest thermostat? [duplicate]

I have an older thermostat I'd like to replace with the more modern Nest thermostat. The online Nest compatibility checker tells me that I have a compatible device. However, I'm not sure how it could ...