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

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1answer
30 views

Central air winterization and insulation

Do I need to insulate the skinny copper line on the outside to keep it from freezing and bursting during the cold winter months? Anything else I need to do winterize the a.c. unit?
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0answers
230 views

No C wire terminal on my electric plenum but there is on my furnace. How do I solve?

I had a brand new furnace installed recently but also now picked up a wifi thermostat. The problem I now encountered while installing the thermostat is that my system also has an electric plenum as ...
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2answers
169 views

Rain water leaking around attic furnace

I bought a house a few months ago and when I bought it I noticed what appeared to be a water spot on the ceiling of the top floor. Of course I didn't do anything about it until heavy rains over the ...
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2answers
48 views

Air handler unit stops running. Starts when motor touched with metal

How is it going? I just moved into a place I bought. It has separate AC units for both floors. We started having an issue with one of the air handler units. One night when turning the air on the ...
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1answer
609 views

Correct Wiring for Furnace Blower Motor

After getting my furnace blower motor replaced, it now runs only in the following scenarios: 1. Mode "Cool" Fan "Auto" 2. Mode "Cool" Fan "On" 3. Mode "Heat" Fan "On" In other words it will not run ...
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2answers
2k views

Hvac Fan only blows in 'fan on' mode while heating

Our HVAC Fan only blows in 'fan on' mode while heating. In other words the fan will not blow in heat mode if switched to "fan auto". Both fan on and fan auto modes work when cooling. See image below, ...
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0answers
32 views

Temporary Remove Flex Duct

I am about to replace a load bearing wall in unfinished basement. There is flexible duct attached to plenum that I need to temporarily move out in order to put the beams in. Do i just need to cut ...
1
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1answer
181 views

Why isn't my Lennox G26Q3/4-100-6 furnace firing up?

I replaced the batteries, does not click when it calls for heat in the thermostat. fan blows but no heat. I took off inspection door, held the safety switch in, a blue light is blinking constantly, ...
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1answer
111 views

Hvac fan runs and shuts off in a cycle when in heat mode

I have a Heil hvac model. N44336336GKE100, The system works ok when in cool mode but when in heat mode the outside fan runs for 30 sec then shuts off for 20 sec and continually repeats the cycle. I ...
2
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1answer
252 views

What is the optimal duty cycle for a furnace?

A heat load calculation of my home says it requires ~36K BTU/hr of heat at a normal winter temperature (40°F), and ~52K BTU/hr at the design temperature (24°F). An HVAC contractor has proposed ...
1
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1answer
78 views

Home Air Conditioner Problem

I have an air conditioning unit that was here when I bought the house. It was in the 70's here today, but I have an old house and windows don't open so the house was hot. I decided to turn on the ac ...
2
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1answer
39 views

If water level is rising on its own on oil heating unit instead of going down, could I have a leak? Or something worse?

If water level is rising instead of lowering on oil heater unit, is there a leak? Could something worse happen. Oil man had to drain water to lower water, and said to watch it to make sure it doesn't ...
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1answer
60 views

How do I compare furnace models?

I need a new furnace, and I have quotes from two companies, for three different brands of furnace, Carrier, Trane, and Lennox. Both companies have provided the model numbers of the units they would ...
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1answer
101 views

New Thermostat installed but compressor comes on immediately

I have a new Insteon Thermostat that I'm using to replace my prior Honeywell t-stat. This is installed to a relatively new HVAC system (both AC and Heat) that DOES have a "c" wire. I've attached the ...
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0answers
23 views

Is there a “bending rigidity index” of some sort for semi-rigid aluminum ducts?

Some semi-rigid aluminum ducts bend easily and others do not. I want to purchase semi-rigid aluminum ducts online of a specific bending rigidity/stiffness that minimizes sagging but can be easily ...
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0answers
142 views

What makes a furnace pilot valve whistle?

I have a furnace that started whistling, recently. I have read that gas pressure changes can cause this. Others have remarked how seasonal gas changes can lead to a properly-adjusted furnace to ...
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0answers
18 views

Installing a Wifi Honeywell Thermostat with a C wire [duplicate]

can someone please help me out here. I'm installing a Honeywell Wi-Fi Thermostat and this Thermostat requires a "C" Wire. Can someone please tell me by looking at the pictures attached if I have a "C" ...
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1answer
54 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 in-...
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2answers
902 views

Wifi Thermostat to Reznor Garage Heater. No “C” wire connection on terminal strip

I just had a 75000 btu Reznor UDAP garage heater installed. Can I run a "C" wire for a smart thermostat if I don't have a C connection on the terminal strip? There is a C connection on the circuit ...
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1answer
198 views

New thermostat wire: maximum number of wires?

Background: I'm upgrading from a failing ecobee smart thermostat to an ecobee3. The ecobee3 requires all wires for the components it controls to be run all the way to the thermostat (including ...
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0answers
28 views

Pellet Stove Ventilation

I have an Englander PDVC pellet stove that came with my house when I bought it in the spring. Never used it. Currently its vented through the wall and comes straight through the exterior of the ...
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1answer
139 views

Which direction is the airflow through my furnace?

There's multiple lines of ductwork along the side, and up top. So what's the correct direction of airflow (red or green in the image below)?
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0answers
28 views

How to connect 4 fan coils with one wall control thermostat?

I have 4 fan coils (Sabiana sk-22)and I want to connect them with one wall control thermostat. How can I do?
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2answers
1k 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 ...
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1answer
45 views

Can I vent room air to the outside?

The building interior gets hot during the day and stays hot during the evening when it is much cooler outside. It would be a really great option to simply vent the hot air outside instead of having to ...
2
votes
1answer
663 views

Air conditioning unit sitting on the ground

We've lived in our house 11 years. Our air conditioning (condenser) unit, the big boxy thing sitting outside, is not sitting on a concrete slab. It's just sitting on the ground and we noticed this ...
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2answers
131 views

Can a 110v 3-wire thermostat be hooked up to a 110v 2-wire condo setup?

My condo that was built in 1968 has an old thermostat(rheostat type) which supplies 2 thick gauge black wires of which one is live and the other isn't. This regulator is hooked up to a blower unit(fan)...
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1answer
59 views

How to remove old A/C piping in my house?

When I had my new A/C installed I moved it to the other side of my house (right next to the furnace), so now I have a bunch of old copper piping running about 30 feet from one corner of my house to ...
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3answers
217 views

Is an HVAC license required for DIY home owner AC installation in the State of Georgia?

Does anybody know for certain if in the State of Georgia, an HVAC ("conditioned air") license is required in order for a homeowner to install their own HVAC system?
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2answers
123 views

Is the Thermostat Wiring Correct

When I moved in to the house the first thing I changed was the old mercury style T-stat to a digital one, I went wire for wire, and it has works (knocks on wood) so far. Now that I have been reading ...
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3answers
102 views

My Goodman a/c motor fails due to high voltage

I have got a brand new goodman unit. The motor kept stopping after few hours an the tech replaced the motor. It still had same issues.. I was told that the voltage coming into the unit is too high.. ...
0
votes
1answer
65 views

what is the cause whereby compressor working gets hot and stops, after cooled down picks up

My challenge was that, I have this refrigerator I'm working on and after awhile it is working and then the condenser become hot as the compressor discharges excess heat, which as time goes on ...
0
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1answer
101 views

Downsides to staple up radiant heat, besides cost?

I'm considering doing a radiant heat retrofit into my home and removing an older forced air system. The plumber is proposing a staple up from the basement into aluminum plates with PEX tubing with a ...
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1answer
41 views

How to control system with 2 condersors+evaporators and 1 blower

I have problem with the control the HAVC system using 2 condensors + 2 evaporatora with one blower. I used 2 thermostats (4 wires/thermostat) to control. But the problem is when i turn on (cool ...
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1answer
105 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. ...
1
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1answer
1k views

AC Blower running very slowly

I have a Ducane heat pump. When running in AC Mode, the outdoor fan and compressor kick off just fine. The blower fan seems to kick off as well, though it's not putting out very much air. I can ...
1
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4answers
111 views

Why is humidity high from one unit but not the other?

Two months ago, I posted about our upstairs a/c not cooling all of a sudden. I ended up replacing the capacitor for the blower fan and the contactor, which did the trick. AC cools!!! However since ...
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2answers
79 views

The house is not cooling

What would cause the outside ac motor to run than stop than start up again and continue this random stop and start cycle constantly. The house stopped cooling
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1answer
159 views

central A/C Turns back on 30 seconds after shutting off

First of all, the a/c system is probably 30 yrs old. The outside unit stays running when the inside unit shuts off. After about 30 seconds, the inside unit turns back on again, and will sometimes only ...
0
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1answer
54 views

How can I plug a hole cut in a window pane for a portable A/C unit?

I just moved into a room where there is a portable A/C unit. To create a vent for the unit, a hole was cut in the glass of one of the window panes that spans about 13.5 cm. I was told that the unit ...
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0answers
65 views

Smaller Footprint of new Furnace Base Cabinet

Replaced downdraft furnace in 1950's ranch house built on slab. Base cabinet of new furnace has a smaller footprint than the original resulting in a 4in. gap between the edge of the cabinet and the ...
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2answers
880 views

Temporary fix for bad contactor?

After doing some replacement for the ac, the contactor stopped working. It won't close when I turn the ac on. when I pushed it in, the compressor was able to start. I can't go out to find a new one ...
1
vote
1answer
50 views

HVAC tripping breaker - things to check before replacing?

HVAC system (we're in Houston, it's still hot here) stopped working Tuesday. A/C guy came out, determined it was tripping breaker. Would trip immediately after resetting, but after a couple of ...
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0answers
43 views

Can my A/C unit knock out my whole trailer or is it coming from the main box outside causing the problem?

I'm confused. Do you know if my air conditioner unit would blow out the main power in my whole trailer if the box inside my house isn't tripping? It keeps making a very loud popping noise under my ...
2
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4answers
2k views

Can a homeowner without a Section 608 EPA license legally connect his own gauges to his own air conditioner if the unit uses 410a refrigerant?

It has been suggested by at least one moderator on this site that EPA Section 608, which restricts who can purchase and handle refrigerant, including who can connect a set of manifold gauges to a unit,...
4
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4answers
299 views

Is transitioning to all electric heating smart?

I am in the process of overhauling my home heating and plumbing. I bought a 2600sq/ft 1980s Cape Cod in southern Maine on the coast. I've reinsulated the walls and roof and am continuing to make ...
2
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1answer
70 views

How to manually control HVAC without thermostat?

I would like to create a solution (Probably with Arduino) to control my AC remotelly. Opening my thermostat and doing some tests I got these values bellow: Blue (C) - Neutral (AC) Red (R) - Phase ...
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1answer
36 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 ...
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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?
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2answers
105 views

HVAC System Just Installed Yesterday and AC condenser outside is blowing cold ir

HI my just installed ac condenser is blowing cold air out side . when I put my hand over it and move it around most of the air is hot but a portion of it is cold. Is this right ?