Questions tagged [hvac]

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

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0answers
18 views

Eliminate Humidistat

I have an old Honeywell H8808 humidistat and a Pro 1 model T721 thermostat and the problem is that when the humidistat is turned down far enough to kick the system on it will come down to set ...
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1answer
2k views

Can I have a separate thermostat for a wood boiler?

I want to wire a separate thermostat for my outdoor wood boiler so that just the furnace fan will come on without the propane kicking on. This is a Coleman furnace. Is this possible and if so, how ...
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1answer
4k views

If you reduce a 8“ duct to 6” just before a register boot, does it produce more force through the opening?

I figure this is probably true if there was nowhere else for the pressure to go, at least in terms of water. Is this true for air pressure even considering there are other paths for the air to move ...
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1answer
79 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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1answer
222 views

Can I fix damaged AC line insulation with tape?

The foam insulation around the suction line on my ac has deteriorated, so I covered it completely with tape. Was this an OK thing to do. Am I harming anything? I have not run my AC since I did this.
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1answer
71 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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4answers
25k views

Why does my window air conditioner cool but not dehumidify?

I have a brand-new 5000 BTU Frigidaire window air conditioner, and it seems to work fine except that it doesn't reduce the humidity in the room. I turned it on last night, and the temperature was 81 &...
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3answers
81 views

What could be the sources of humidity that build up in a house in an arid environment? Outside RH: 10%; Inside RH: 40% +

We open our window at night at the temps get down to 70F @20% RH. The temp in the house drops to 75F and the RH is 33%. We close our windows when we go to work. When mid day comes, outside, the ...
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0answers
29 views

I am installing a Honeywell Pro 2000

So, I have the green, white, blue and red wires coming in, but DO NOT have a yellow. There is a brown. I do have both regular gas heat, and AC. What terminal should the brown wire go? And should the ...
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3answers
253 views

Can I add a second thermostat in my basement for more control?

I would like to install a second thermostat on the lower floor of my home. My thinking is that when we have guest staying on the lower floor I could turn the upper floor thermostat off and the lower ...
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1answer
37 views

a/c condensation line not draining

I have a unit that is installed in the attic and is about 2 years old. For the first year everything was fine and then one day it wouldn’t run. So I hooked up the shopvac and sucked the condensation ...
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4answers
98 views

AC air feels unnatural

I have a general question concerning air condition systems. Basically to me the air coming out of the AC unit doesn't feel natural. I've experienced different types of AC units, from small to quite ...
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7answers
10k views

Why does my house heat up, even when it's cool outside?

Summary The question pretty much says it all. It's probably a ridiculously easy one to answer. It's cool outside but I know that my house is heating up because my AC kicks on periodically. I've ...
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1answer
31 views

Secondary C Terminal on Furnace Circuit Board?

I was trying to install an Ecobee thermostat, and there was no C wire installed. When I went to install the power extender kit, I saw the standard C wire terminal was broken out of the black plastic ...
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1answer
91 views

Which humidistat terminals should I use for my humidifier?

My Carrier furnace does not have a humidifier connection on the control panel. I have two wires from the humidistat. Do I use W-C or R-C connections for a normal operation?
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1answer
36 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
65 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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2answers
54 views

Heat pump not working after rain

A couple weeks ago, I had a Goodman 3 ton heat pump split system put in. At 5pm hours today, I was outside near the heat pump and noticed that it was functioning properly. At about 6pm, there was a ...
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0answers
10 views

Lennox G51MP shutting down with Primary/secondary switch fault

I have Lennox G51MP-48c-090-06 ~14yrs old, starting up for first time this season. It is throwing error code: Primary or secondary limit switch open. Unit shows normal operation when powered up and ...
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1answer
53 views

Second Floor Bedroom Little HVAC

I have one bedroom upstairs 2nd level that virtually gets no air or heat. The other 2 bedrooms have medium force. For the one bedroom in question, checking with your hand, you feel very little and I ...
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1answer
40 views

HVAC Adding a Common

Got a new Honeywell WiFi thermostat and need to add a common. Currently the 3 common wires per the diagram (BL, BK, GY) are wired to one side of the AC Unit. Is there an issue if I piggy back a ...
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1answer
32 views

Mold at Air Return

I have 2 HVAC units, one for upstairs and one for downstairs. When I went to change my air filter for the downstairs unit I noticed some mold in the return duct. This is a large duct that travels ...
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1answer
39 views

Can I safely jumper between either G or Y and RC at thermostat panel to troubleshoot AC problem?

I'm trying to troubleshoot a non-functioning AC. The fan does not come on and there is no cool air/condenser does not run. My thermostat is a Braeburn. Three things I'd like to try for ...
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1answer
57 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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1answer
42 views

Where should I connect my C-wire on my old Goodman unit (GMP075-4 rev 13)

I want see if someone help me on hooking up this new Honeywell thermostat with Wifi I just purchased. I have an old ac unit and I only have 3 connections to my circuit board which does not have an ...
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1answer
50 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
60 views

No power to isolator switch

I recently moved into a repossessed flat and the electrics were a bit of a mess. Sockets, switches, etc. hanging off walls but it has since all been made safe/good by an electrician. The only thing ...
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0answers
18 views

Geothermal system that will not always cycle down at set point

I have a Geothermal HVAC system (no outside unit). Occasionally it will continue to run well past the set point and not cycle off. It may do this once in a week or once in a few weeks. If I turn the ...
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1answer
48 views

Furnace with no “C” connection

I have a mobile home furnace. This furnace only has a 4 wire connection terminal, G,W,R,Y. I also have a condensing unit outside with the 24 volt 2 wires coming to the furnace. I know I connect one to ...
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1answer
40 views

Ducted A/C system under powered

I recently replaced carpets with tiles in my apartment, and in the process generated an incredible amount of dust. All this dust was sucked into my A/C ducting, and the filters in the return were ...
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0answers
18 views

The burner on my Lennox G40uh furnace will not ignite

I have a Lennox G40 series furnace and the gas valve will not open. After it does the preliminary start up I get 27V to the gas valve, but only for about half a second. Periodically the LEDs will ...
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1answer
22 views

Blue star inverter spilt ac 1.5 tonn

In my spilt ac the big pipe in the outdoor gets freeze when running ac on low temperature but not frezzing when it running in higher temperature. What is the fault if the gas is low in the compressor....
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1answer
86 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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3answers
4k 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
74 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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2answers
48 views

Going through condensate pumps every 2-3 years

I am about to buy my 5th condensate pump in 12 years. HE furnace or 2.5T A/C run 10-11 months out of the year here. Humidifier attached but not in use. I have a 7.5' rise, 20' horizontal span, then 8'...
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1answer
41 views

Direct vent boiler exhaust exiting close to brick chimney

The exhaust vent for our Burnham Spirit direct vent boiler currently exits very near the junction box where I recently installed an IR-triggered motion-sensitive floodlight. The hot air is causing ...
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1answer
20 views

How should I insulate garage ductwork when no gap exists between ductwork and ceiling?

I currently have uninsulated HVAC ductwork running the width of my garage. There's no gap between the ducts and the plaster ceiling above it. There's also very little clearance between the ducts and ...
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1answer
40 views

Goodman GMNT100-4 Unit- Blower Motor Works for Air But Not the Heat

I have a Goodman GMNT100-4 that air conditioner was working great. However, I recently turned on the heat. The system goes through all sequences fine until it's time for the blower motor to kick on, ...
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1answer
53 views

1999 Goodman furnace modeld GSMS060-3

Furnace goes through the normal start up process but after 5 minutes the flames go out and I hear a click in the induction motor not the main fan. What could I check. I have taken out the flame ...
0
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1answer
37 views

Why doesn't my HVAC system use the away temperature setting?

I have a Carrier Infinity dual-fuel 5 stage HP w furnace. I set the away temp much lower than the home temp but the HP keeps running to bring the temp up to the next home temp. I would think the ...
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1answer
20 views

Heater tripping off outside breaker

I have a Payne AC/Heat unit outside my mobile home. When I turn the thermostat to heat, it runs and blows air for about 10 seconds and then trips the outside breaker at the meter... From the meter I ...
0
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2answers
39 views

Gas heater fan noise

I have a CF653C-H Cozy wall gas heater ..The fan runs fine , except when it shuts down , it clicks 15 to 20 times before stopping . At least I am guessing its the fan, could also be the motor ..But ...
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2answers
262 views

A/C unit cycles on and off during cooling phase

My outside compressor / condenser is cycling on and off, even though the thermostat is calling for A/C. The blower in the house still runs, and the thermostat is working properly. (I opened up the ...
1
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1answer
129 views

Converting I+ I- thermostat to 'standard' wiring

I've been replacing my thermostats with the RadioThermostat CT50, which reports to my home-brew home control/alarm system. I have a 3-year old AireEase 4-ton unit in the shop that has a Comfort Sync ...
1
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1answer
44 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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2answers
83 views

Fill leakage gaps/holes in AC condenser cabinet?

Is the condenser unit engineered to be optimal with a leaky cabinet? Any reason not to pimp it up, blocking air leaks? While I was troubleshooting my 12+ yo Carrier AC this morning, I vacuumed out ...
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2answers
36 views

Do two-stage compressors offer both two-stage heating *and* cooling?

I received a quote for a two-stage heat pump (model HCH636GKA). I have the following questions: Does a "two-stage heat pump" imply a two-stage compressor? Does a two-stage compressor guarantee two-...
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1answer
57 views

A/C blower does not work after a power surge

My outside unit works but my inside unit does nit turn on, its a bryant a/c system. On the unit it says the circuit board is built into the blower motor. The transformer buzzes. Can I replace the ...
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3answers
35 views

combining a humidifier with refrigeration cooling, what do you think?

I live in a high humidity (75%) climate. I wanted to know what happens when you combine a light humidifier with a normal AC set on "dry" mode. The AC is activity reducing humidity, which helps me "...