Hot answers tagged

7 votes

Is a fused disconnect essential for mini-split outdoor unit?

The instructions for mine (also Mitsu) say nothing about requiring a fuse - just minimum circuit ampacity and maximum overcurrent protection. Installed by approved Mitsu installers, who were just fine ...
user avatar
  • 132k
6 votes

Wiring single-phase A/C to a 240V 'wild leg'?

Primary issue: there are no 240V straight rated single pole breakers in the QO line Your first problem is that you can't just use a single pole breaker for this job, as all single pole QO(B) breakers ...
user avatar
6 votes
Accepted

Why would a fusible AC disconnect require a bonded neutral when a non-fusible disconnect only requires the equipment grounding conductor?

A fused disconnect can be a main disconnect and if used as a main or service entrance disconnect the neutral is required to be bonded by code. A non fused or safety disconnect requires over current ...
user avatar
  • 95.5k
6 votes

What is a Non-automatic AC Disconnect

A "non-automatic" disconnect is a molded case switch in a box All fusible and most non-fusible AC disconnects are of a type known as a "pullout disconnect" where there are fuses or ...
user avatar
4 votes

How to Interpret/Calculate HVAC Load Impact from Rerigerators

The reach-in refrigerators will add exactly their operating wattage to the room, and no more. Wait. What about all the heat they're removing from the interior of the refrigerator? Aren't they adding ...
user avatar
4 votes

Is a fused disconnect essential for mini-split outdoor unit?

Code requires 3 things: Circuit breaker or fuse protection appropriate to the unit, but that could be anywhere. A disconnect (fused or unfused) near the unit so maintainers can know it's off - same ...
user avatar
4 votes

What is a Non-automatic AC Disconnect

Non automatic disconnect is a switch that requires a person to disconnect (no fuses). There are really inexpensive one that has a shorting bar that is pulled out. This is the most common type in use ...
user avatar
  • 95.5k
4 votes
Accepted

Found a 2"x4" hole in return duct

It sounds to me like someone was planning on installing a return into the bathroom. A return is NEVER to be installed in a bathroom, so there wouldn't have been one, and you said there were also no ...
user avatar
  • 56
3 votes

If you tilt a air-conditioner will it keep it from coming on

If you tilt an air conditioner to any position other than normal, compressor oil can migrate into the refrigerant lines. This prevents high pressure refrigerant gas from passing through the lines ...
user avatar
  • 2,949
3 votes
Accepted

Rust on outdoor ac fan motor? Tech recommends replacement?

GET A NEW AC GUY!!! Most motors have a external laminated iron core and cast end bells. This metal when outside may rust that is what happens to the iron. We do paint motors when we rebuild them to ...
user avatar
  • 95.5k
3 votes

Does any manufacturer make a fused 240 V 60 A steel AC disconnect with GFCI receptacle?

Typically, the mandatory A/C service receptacle is fed from a different and unrelated circuit. Usually this is an "outdoor outlet" circuit that is already there, and already has GFCI ...
user avatar
3 votes

Identify pipe connecting to nothing in basement (fireplace/hvac/unsure)

Best bet: an incomplete fresh outside air intake so that your fireplace wouldn't be sucking heated air out of your house. The "outside" part of it does not seem to have been done if it just ...
user avatar
  • 132k
3 votes

Is a fused disconnect essential for mini-split outdoor unit?

When I was installing my outdoor condenser I asked my journeyman electrician friend about fused, unfused disconnects, and breakers. His reply was as follows: A fused disconnect is a single point of ...
user avatar
3 votes
Accepted

Why is my Google Nest Learning Thermostat (3rd Generation) not getting power?

Turns out I had blown the 3-amp fuse in the air handler when installing the thermostat (I crossed some wires). In case it helps someone in the future, the printed figure at the top is a 3 to indicate ...
user avatar
3 votes

Can I add an extension to an air intake for apartment central A/C? Is this a health or code violation?

If the air conditioning is not properly drained, the condensation will drip down into that section underneath which can cause mold. I also notice a hot water tank in the area. Another source of ...
user avatar
  • 31
2 votes

Can I set a portable AC unit back in a dormer window?

I've had a similar problem: the window was too tiny to fit a window AC unit. The problem with portable AC units is they have only one pipe to the outside. A normal window AC unit has one airflow ...
user avatar
  • 5,780
2 votes
Accepted

How to Interpret/Calculate HVAC Load Impact from Rerigerators

The reach-in refrigerator will add all the heat it's removing from the cooled space, PLUS all the waste heat generated by the motor and compressor that's not contributing to moving heat from the ...
user avatar
  • 132k
2 votes

Gain access behind Daikin ductless air conditioner indoor unit

Call a qualified technician. There is no slack in the copper piping. Those pipes are bent in place and are fairly rigid. A small mistake will create a refrigerant leak, collapse a pipe, stretch the ...
user avatar
2 votes

Wiring low voltage at old AC split system unit

Given the wiring, it looks like you have the American bog-standard "forced-air furnace, with basic air conditioning unit bolted on" (in fact, an outdoor unit + an evaporator in the furnace ...
user avatar
2 votes

Can I pigtail a "C" common wire to power a Smart Thermostat to the 24v wires coming from the outside AC compressor?

I was able to answer my own question here. By knowing what wire from the outside compressor is connected to the wire going to the "Y" on the thermostat (in my case it was the white wire ...
user avatar
2 votes

What is this box on my HVAC duct?

It appears to be a motor mounted to the duct work to control a damper that will open or close to allow more or less air to flow through the duct. This is likely to control temperature in a "zone&...
user avatar
  • 29.1k
2 votes

How to seal this type of window for portable air conditioner?

A sheet of plywood. Most better lumber yards will sell you a cut piece to your specified dimensions that will sit inside the notch on the inside. You can then cut the openings exactly as you need ...
user avatar
2 votes

How to seal this type of window for portable air conditioner?

Ignore the window. Seal a flat sheet of something to the window frame on the room side, with a 6" hole in it for your duct. Something - Plexiglass or other clear plastic sheet if you want the ...
user avatar
  • 132k
2 votes

Whole House Fan Emergency Shutoff / Limit Control

I would recommend using a device designed specifically for your concern. Here's an "attic fan fire safety switch" (from Home Depot). No, it's not resettable. No, you don't want to "...
user avatar
2 votes
Accepted

A/C Evaporator Coil - Water dripping from unknown fitting

(From OP) I found this image online, which I believe is what I have in my coil box: If the primary drain (right outlet) gets clogged or partially clogged, the condensate inside the evaporator will ...
user avatar
  • 21
1 vote

Should the door be open or closed between two separate HVAC systems?

Having lived in a similar type arrangement, the efficiency of each unit shouldn't drop any significant amount. Any registers should be aimed away from the door in question. I think you'll fine there's ...
user avatar
  • 53.2k
1 vote

Is there a safety issue if my window AC causes lights to dim?

Is there a safety issue if my window AC causes lights to dim? Not usually, no. This is normal with high draw startup items like A/Cs, vacuums, and microwaves. The bigger issue is having sensitive ...
user avatar
1 vote

Is there a safety issue if my window AC causes lights to dim?

A 12000 BTU AC unit will, depending on its efficiency, consume 1200-1500 Watts. At 120V, which I assume you are using here, that will take 10-12.5 A more or less. Since your circuit is rated for 15A ...
user avatar
  • 20.3k
1 vote

AC blower unit stops working intermittent

So this ended up being the run capacitor. The capacitor was tested and it was found to by below spec/faulty. With a bad run capacitor you dont get smooth power to the blower motor. The motor works ...
user avatar
  • 117

Only top scored, non community-wiki answers of a minimum length are eligible