Questions tagged [hvac]

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

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5
votes
1answer
60 views

How do motor capacitors change in value with respect to age or environmental factors?

Do motor capacitors (i.e. start, run capacitors) change in value with respect to age or other environmental factors? I understand they fail, as observed when the motor will no longer start. Do they ...
0
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1answer
19 views

Fan is turning on air conditioner but no air movement

A few weeks ago I changed the outside unit's starting capacitor and that got the fan on that unit to rotate and the air conditioning on the enclosed back porch started working. Today I came home and ...
8
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5answers
930 views

Why does my air conditioner still run, even when it is cooler outside than in?

Summary The question pretty much says it all. I've had this experience in multiple houses, so I presume it's not just caused by some sort of one-off issue with an AC or thermostat. It seems strange ...
0
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1answer
2k views

How to wire C wire to the transformer of HVAC?

How are you all doing? I tried to connect the digital thermostat (Ecobee3) instead of my old honeywell thermostat. The original wiring is below (figure 1) HVAC is located on the ceiling of bathroom ...
0
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4answers
41 views

What parameters affect the amount of btu required to cool a single room

Background Due to the reason I lack knowledge in air conditioning I asked a company that manufactures and sells a\cs to send a consultant to advise me on which air conditioner I should use in my room....
6
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1answer
1k views

What causes burn marks on the air handler in the attic?

What caused these burn marks? Phoenix Arizona suburb. House was construction complete about 6 months ago. The tape and insulating foam around the bigger tube was cut. I assume the AC tech that ...
0
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2answers
26 views

Thinnest screed over the water heating floor

I installed a water heating floor system with 17 mm pipes and studded panels. This is how a studded panel with a pipe looks like: It has 52 mm height (the polystyrene has 30 mm). Now I want to add ...
1
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1answer
637 views

Can I run a C wire from Fan Relay

We've just moved into a new home with an heat only, oil, forced hot air furnace. The current thermostats are very old and we'd like to update them to something like a nest. The furnace is currently ...
1
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1answer
409 views

Old AC and Gas Boiler wiring for new thermostat

I need help connecting a new 'C' wire for a Honeywell RTH6500WF thermostat. As you can see the heating is an old boilder with a simple pump to circulate the hot water to the baseboard radiators. The ...
3
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1answer
165 views

Can a motorized damper be installed inside existing ductwork?

My HVAC system consists of a fan, furnace, compressor-driven AC, and evaporative cooler. The problem is that there is a large air volume used only by the evaporative cooler that is generating a lot of ...
0
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2answers
27 views

Thermostat “fan” function actually using air conditioning

A few months ago, my wife and I started sleeping with our bedroom doors closed to keep out our cat. We would wake up in the middle of the night to find our bedroom was very hot and it felt really hard ...
0
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1answer
48 views

Room easy to warm with heater. But difficult to cool with A/C. Is this not insulation related?

I live in an apt building in the 60's. I always notice that the room is always warmer than the outside in the winter time(even with no heating). This stays true in the summer time where it would be 65 ...
0
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1answer
6k views

Wiring a Replacement HVAC Blower Motor for an American Standard Heat Pump Air Handler

I undertook what I thought would be a straight forward task.... Needless to say I have run into an issue that I need some help with. The replacement motor is a century 4ka35 motor with the ...
0
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4answers
5k views

How to fill / seal in-slab hvac ductwork?

My house is built on a slab. Within the slab are "channels" which act as ducts for the HVAC system. I assume it is partially lined with metal but based on photos from an HVAC-cleaner, it's hard to ...
0
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1answer
335 views

Thermostat wires crossed? Fan switch runs condenser fan instead of blower

I have been having this problem for a while and have just not run blower without thermostat calling for heat or AC, system seems to run fine in heat or cool mode, but if I turn on FAN by itself the ...
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3answers
55 views

I need to pressurize a room and I'm kind of at a loss as to how to do it, hoping someone out there might have some advice

I'm setting up a small packaging operation for edible products for pets. There are certain government standards we have to hit to be able to do this. The actual packaging takes place in a 420 sq ft ...
0
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1answer
21 views

Mini Split Condenser wall mount on wood exterior wall

We have a wood-frame house with 2x4 studs and half-inch plywood exterior walls. What is the generally accepted best practices for mounting a 80lb mini split condenser on a wall bracket to this type of ...
3
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1answer
53 views

Can I draw 240v out of this configuration?

This is how my subpanel looks like. I am looking to install a breaker for an AC unit. 20A. The only caveat is that this has to be 240V. This is a subpanel coming from the main one. There is a breaker ...
1
vote
1answer
32 views

HVAC Air Blowback

Furnace/Blower: Rheem R92PA0851521MSA Dual Zone System (Honeywell TrueZONE HZ311) - Honeywell M847D1004 Actuators Age of system: less than 2 years old including ductwork Ive noticed that if Zone 1 ...
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2answers
16k views

How can I figure out why the low voltage furnace fuse blows on heat but not cool?

I have a Tempstar Model NTC6100KFG1 gas furnace. Furnace was working fine through the summer blowing the AC. It's been off for a month or two as we've been changing seasons here. When I went to turn ...
0
votes
1answer
837 views

r-410a pressure problem, 285/120 psig

i just installed a new split unit r-410a a/c system. it is running at 285/120 psig. the high side seems way low, should be about 420. the correct orifice is installed. this is a 1.5 ton condenser,...
0
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2answers
33 views

Adjusting HVAC damper

First summer in this 2 story house and looks like air flow on the second floor is significantly weaker then on the bottom floor. Looked at the HVAC to find the dampener handle and found 1 but it is ...
1
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3answers
29k 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 ...
0
votes
1answer
972 views

How can I add a C-wire to a Venstar T5800 thermostat?

I am trying to replace my existing thermostat. My old thermostat has: Rh, W (coming from the heating unit). Rc, Y, G (coming from the AC unit). On the Venstar T5800, I can map as follows: Rh+Rc -...
0
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1answer
132 views

How can I protect an exposed refrigerant pipe outdoors?

I have approx.12 ft. of copper pipe carrying freon laying on top of the ground. Best way to protect it without cutting in two & loosing all freon? (Not enough slack to bury.)
0
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2answers
394 views

A/C freezing lines

Issue: evaporator/suction line freezing up in A/C mode. Actions: Replaced fan motor and evaporator coil (no air coming thru old one/beat up petty bad). Relevant Information: Refrigerant Type: R???...
1
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3answers
61 views

Water/antifreeze radiator cooled work shop

An additional line of thought. Cooling radiators in summer? I found this having the same concept for cooling. I live in south louisiana, US where 95F is vary common turning tin boxes into a slow ...
0
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2answers
137 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 ...
0
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2answers
63 views

condenser capacitor question

My outside condenser fan quit running, so I tested the capacitor, and got nothing on the meter. The cap that was in there was a 35/7.5. The closest one I could find at the time was a 50/7.5. Now ...
1
vote
1answer
27 views

Add common wire to furnace

Trying to add common wire to furnace for smart thermostat. Looking at wiring diagram, it looks like common wire off transformer is blue, switches wire color to white (via wire cap), then back to blue (...
1
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3answers
287 views

Undersize AC unit

We just bought/built a new home. We were not given any options regarding the central ac/heat system. We were told simply the system would be sized to fit the house. Soon after moving in it already ...
0
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1answer
58 views

What is the fully burdened hourly rate for an HVAC installer?

While it's pretty simple to get an hourly rate that is paid to an HVAC installer, I have found it more difficult to ascertain what the fully burdened rate is. This is the complete cost a company to ...
1
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3answers
1k views

Cooling radiators in summer?

How efficient would it be to use radiators circulating with cold water, to cool house in summer? Wondering if anyone has tried this, and how well it works? I was thinking about H/AC in general, and ...
1
vote
1answer
247 views

C Wire placement in HVAC?

I'm installing a new thermostat and the previous one did not have a C wire connected. Tracing in back to the HVAC, I can't see a C output connection? Based on the wiring diagram (and reading other ...
0
votes
1answer
49 views

Return plenum too big for air handler?

I am currently in the process of changing the air handler and heat pump in my house. I am working with a friend's father who does HVAC for a living. He came over and looked at my HVAC system and gave ...
0
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0answers
19 views

HVAC plastic drainage tube snapped off outside

The plastic tube where the condensate drains outside has broken off partly. I would say about 2/3 of it broke off. It still points away from the house a little so shouldn’t get on the wall. Should I ...
1
vote
1answer
229 views

How to handle unattached ground wires in boiler fusebox/control panel (sub-panel?)?

I don't have enough of an understanding of HVAC to know if the pictured boiler fuse box is considered a control panel or a sub-panel - but some wiring issues there lead me to needing to understand ...
0
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2answers
2k views

Indoor blower fan turns on and off intermittently in 10-15 min increments when system is off

Bit of background: The furnace blower originally did not not turn off at all (or if it did, very rarely did so), even when set temps were reached or when the system was off (fan setting is set to auto,...
2
votes
1answer
32 views

Adding ventilation to an older outbuilding

I have a large to me storage building that I am trying to convert into a garage/workshop. I don't have the time/money/inclination to tear the whole thing down and start anew so I am trying to make ...
0
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0answers
16 views

Hvac fuse blowing on furnace board

A 5 amp fuse keeps popping at startup on my tempstar furnace,had a problem a couple weeks ago and put fuse in and worked fine.Now it blows instantly.
0
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2answers
24 views

Placement of a package unit heat pump for my shop

I was wondering if I would benefit by locating my 3 ton package unit heat pump closer to the load center. The ducting would be my only interference with it closer to the load center. The unit would ...
1
vote
1answer
59 views

Why the noises in the new furnace?

A company installed a new HVAC system 2 weeks ago. The furnace model was new: 58TNOA110C21–20. I initially ordered 58CVA110-20 but they said it will be out of market soon in August. So they installed ...
1
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1answer
214 views

How should I jumper the transformer to use a thermostat with my heat pump?

I am hooking up an aftermarket blower motor on my Trane XL 1400 AC/heat pump. I have a black, blue, red & white wires coming out of the new motor. I am bypassing the circuit board so I am ...
3
votes
3answers
28k views

Better to run air conditioner fan on high or low speed?

In my apartment, I have two window air conditioning units. Both have different settings for the fan speed: one has two speed options and the other has three. Both have the design that the room ...
0
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0answers
37 views

Split unit Air Conditioner replace compressor single to three phase

I have a 3-ton split AC "single-phase compressor" was working perfectly until I moved it to another location, some oil spilled from the suction pipe during the transportation so when I installed it in ...
0
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1answer
183 views

Oil furnace fan won't shut off when “heat” plug is connected to control board

I was changing my thermostat and I attempted to make the swap live without turning power off. When I connected new thermostat, the fan kept running. Ruled out bad thermostat and wire short by ...
1
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1answer
111 views

Thermostat C Wire (Possibly Unconnected)

I purchased a Honeywell RTH6500 Wifi Thermostat, which requires a C wire. My old thermostat showed a connected blue C wire. However, it was battery-powered. If I removed the battery, the thermostat ...
1
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2answers
2k views

Why does my electric furnace sometimes blow cold air?

I have an electric furnace that blow cold air sometimes. I replaced the thermostat and that did not fix it. The fan blows fine. If I shut if off for a few minutes and then try again, about half the ...
0
votes
1answer
176 views

Connect Wifi Thermostat to Goodman GMP050-3?

I'm trying to connect up a wifi thermostat to Goodman furnace, specifically the GMP050-3. I've done some reading on this but I'm still not quite sure how to go about it. Specifically, I'm not sure ...
1
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1answer
19 views

Fan on propane furnace not coming on

I have a Honeywell model number NHGK076AF01 propane furnace. It is about 15 years old. The problem started when I noticed the breaker had tripped and I had no heat. After resetting breaker, I tried ...