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

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2
votes
3answers
134 views

Will a 2-stage heat pump cool my upstairs on low stage?

I am currently upgrading my furnace from an oil furnace/AC combination to all heat pump. I am considering two stage vs single stage heat pumps. I understand that two-stage will supposedly give me ...
2
votes
2answers
518 views

Is there a way to turn on the air conditioning only on certain days?

We're looking for a way to turn on the air conditioning at our camp, say on a Thursday night, so that it will be cool when we arrive on Friday evening, but to shut it off if we don't go to the camp ...
2
votes
2answers
2k views

Is a little ice on the cooling coils ok?

This is our first summer in a new house which has central air. It was a bit hotter today than normal so the AC was running for a long time. After awhile we noticed the airflow stopped because the ...
2
votes
2answers
466 views

How much current should I expect this motor to draw when it's running steadily?

This fan lists its "Max. Amperage" as 3.2. I assume the motor draws that much when it's first turning on, then settles down to some lower current. How much current should I expect it to draw when it'...
2
votes
1answer
36 views

Why doesn't AC equipment come with dehumidifier only option?

Every AC unit dehumidifies when cooling is on. I'm just wondering why dehumidification only is not an option, as is in standalone dehumidifiers? E.g. my basement stays pretty cool even in the summer ...
2
votes
3answers
916 views

How to measure air flow coming out of registers?

As my contractors finish installing ductwork and the air handler for my central AC system, I would like to have a measure of how many CFMs come out of each register, as a function of how the system is ...
2
votes
4answers
17k views

How can I calculate the power consumption of an A/C unit?

I have an AC unit with the following specs: Cooling Capacity: 1260 kcal/h, 1.47kW, 5000 Btu/h Fan Motor Power: 0.034 kW Current: 0.155 A My question is how much power does this unit actually ...
2
votes
2answers
5k views

What does this square icon mean on my Honeywell thermostat?

I have upstairs Honeywell Thermostat showing me a square icon since yesterday. The upstairs AC is not working. It is blowing air since the fan is on but the air is not cold. I opened up the ...
2
votes
3answers
4k views

What is going on with my central air?

I have a re-occurring issue with my central air. I have changed filters, cleaned all three intake vents and even had a serviceman out on three different occasions (two separate companies). My problem ...
2
votes
1answer
308 views

Will an electronic air filter harm my furnace?

If I install a furnace-mounted, electronic air filter, like this one, will it harm my furnace due to reduced air flow? How will I know if it reduces air flow too much?
2
votes
2answers
1k views

How do I lower a cold air return from the ceiling for a basement rental?

I am living in the basement level of a rental unit with forced air heat. There are 9 heating vents and one cold air return, all of which are in the ceiling. The air isn't mixing very well resulting ...
2
votes
1answer
84 views

What components need to be changed when upgrading from R22 to R410a?

What equipment will change when I convert from R-22 to R-410A? I don't want to get rid of my current heater as it's a hydro-thermal unit that uses free heated/recycled hot water. Can I get away with ...
2
votes
3answers
336 views

Would it be a bad idea to use two air filters?

The filter in our central air/heat is directly under the unit and very difficult to replace filters. Even though we use 3 month filters, we replace them monthly due to pet hair/dander. It's a pain to ...
2
votes
2answers
63 views

Cost of adjusting the thermostat

Is it more cost effective to (1) play with the thermostat by lowering it at times that you're not home or needing the heat and raising it back later or (2) leaving the temperature on a set amount and ...
2
votes
3answers
8k views

Can I cap the air return in my unfinished basement?

I noticed today that there is a massive air return in my unfinished basement. The opening is about 2 meters from the blower, and as large in diameter as the return duct coming from the upstairs. This ...
2
votes
2answers
3k views

At what temperature should an unoccupied house be kept at in winter?

We are moving to a new house and unfortunately we don't have our house sold yet. I was wanting a recommendation as to what temperature to keep the furnace going @. I found a good recommendation to ...
2
votes
2answers
13k views

How should I evaluate my central A/C to see if it's working properly?

I was once told by a service tech that they evaluate how well the system is performing based on temperature difference between the the return and supply sides. On our first really warm day (80F+), I ...
2
votes
4answers
30k views

What to do about different rooms in the house being a completely different temperature?

I moved into a 30 year old home last December. There is a problem with the HVAC. I have included a very crude drawing of the floor plan The problem is that I can't maintain a comfortable ...
2
votes
1answer
13k views

Which way does the air flow through my furnace?

Below is my furnace and I need to change the filter however I am unsure which way is the airflow direction. Red or Blue?
2
votes
1answer
500 views

Breaker box or heat pump problem?

We ran our forced air heat pump today. 15 min. in we noticed it just stopped running. Looking in the breaker panel I could see that the breaker for the heating unit had tripped. When I tried to ...
2
votes
2answers
4k views

Furnace flashing 4 times (Ducane)

My Ducane furnace flashes 4 times, runs for 5 minutes, and then the burner goes off. When the limit switch is jumped it runs good. What needs to be changed here?
2
votes
2answers
2k views

Can an 18 inch duct be replaced by 4 smaller ducts?

We have a return air duct that is 18 inches in diameter that had to be soffited. Not a big deal except it is taking up closet space in what is otherwise a very small closet for a kids bedroom. Can ...
2
votes
2answers
345 views

Why is my AC suddenly *heating* my house?

I have a 13 SEER heat pump about one year old. Everything's been working fine, but the AC suddenly started heating my house spontaneously (no changes to thermostat, etc). The outside ambient ...
2
votes
1answer
4k views

Why isn't my heat pump system kicking out cool air this year?

I have a Carrier heat pump/air handler system (looks pretty old) with a honeywell T-stat (looks pretty new) and I am not getting cool air. Heat worked all winter, but I have used it in at least a ...
2
votes
1answer
626 views

Replace 7“ metal duct with 6” flexible or 8" flexible?

I am replacing the flexible ductwork in my attic, which is a mix of ancient 6" and 7" metal ducting. I'm having a hard time finding 7" flexible ductwork for sale locally, but no problem with 6" and 8"...
2
votes
1answer
6k views

Why is there water dripping from my ceiling AC vents?

I have a one story house with hot water heat. The house also has forced air AC ducts running from the attached garage, in the attic, down into the living room, bedrooms, and kitchen. At certain times ...
2
votes
2answers
2k views

How do I clean an AC condensate pan?

I have a Ducane HVAC system that started leaking out of the evaporator coil housing. Mine looks like the EU1P. I read that i need to clean out the drip pan. II tried cleaning it by sucking out the ...
2
votes
2answers
24 views

Zoned heating system very warm even without heat on upstairs?

I know heat rises, but our 1st story floorplan house gets pretty darn warm during the winter months. Other than turning on the AC or opening windows in the upper story zone, anything else that could ...
2
votes
1answer
41 views

0v at DC thermostat terminal in furnace

I have an old (mid 80s) Rheem gas furnace I hope will last me through at least one more California winter. It's been known to go down into the upper fifties, so it has its work cut out for it. In any ...
2
votes
2answers
696 views

Should I convert from a rooftop to a split HVAC system?

We have a packaged HVAC on the roof and the AC needs to be replaced. It's 23 years old and dying/dead. We were considering buying just an AC and keeping the package unit running for heat. We feel ...
2
votes
1answer
169 views

Is there a reason for an exterior vent not connected to anything?

I have an exterior vent on the side of my house not connected to any piping within. You can look inside and see wood/concrete/insulation into the cavity between the basement ceiling and main floor. I'...
2
votes
2answers
3k views

What can cause an A/C to freeze up

Our A/C evaporator coil freeze up last year, so I called out a technician. He said that it was charged with the proper amount of Freon, and my problem [paraphrased] "something had narrowed the inside ...
2
votes
2answers
590 views

How can I prevent my clothes dryer door from fogging up?

When I turn the air conditioning on in my house, the inside of the window in the clothes dryer door fogs up. Also, if clothes are left in the dryer, they become slightly damp again. How can I prevent ...
2
votes
2answers
4k views

Can you terminate more than one common on the furnace C terminal?

TL;DR: Can you terminate more than one common on the furnace C terminal? Background: I've linked a diagram of how my non-programmable thermostat is currently hooked up. I want to replace it with a ...
2
votes
1answer
552 views

What is involved in sizing and designing ducts and ductwork?

I have a one-story house, and it looks like it would be easy to run new ducts myself in the attic. What should I know before trying to design a duct system myself? I have seen ductwork that's metal ...
2
votes
1answer
3k views

What could cause a replacement A/C condenser fan motor to only run for 3 minutes?

Just replaced a GE 5KCP39FG Condenser fan motor with an AC Smith FSE1026SF. HVAC Counter sales told me it was the right one and gave me a Partners Choice Capacitor 01-0085 to match. Old motor 3 ...
2
votes
3answers
4k views

How can I improve hvac air flow to my attic?

Two years ago I converted the attic of my 1.5 story house into a livable space. It had no HVAC ducts going up, so I ran some coming from the basement where the furnace is. Air flow to the attic via ...
2
votes
1answer
3k views

Does an air return duct do anything when the air conditioning or furnace is not running?

I recently had a contractor create a new wall which cut me off from the rest of the house. There is one AC/Heating vent in the room and when the door is closed it gets very, very hot. As soon as the ...
2
votes
1answer
151 views

When I set the thermostat to X degrees, is that the temperature at which air is pushed out through the vents?

My hunch is that most ac units aren't that sophisticated, and they just pump air that is "cold enough" or "hot enough" and pump it until temperature rises to the specified value. Is that right?
2
votes
1answer
3k views

Is it normal for A/C performance to improve when vent covers are removed?

I recently moved my office to the second floor of our home and I haven't been able to get the temperature below about 78 even though the thermostat is on 72. My son's bedroom had been the same way ...
2
votes
2answers
408 views

Air conditioner not blowing cold air

My HVAC system had a problem during the winter where the blower motor stopped working. I got a HVAC tech to come out and replace it. However, now that it's hot again, the cooling system is still ...
2
votes
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 ...
2
votes
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 ...
2
votes
2answers
901 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 ...
2
votes
1answer
637 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 ...
2
votes
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,...
2
votes
1answer
69 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 ...
2
votes
2answers
745 views

Do I need an HVAC vent in this bathroom?

The finished portion of my basement was completed after the original construction. I've found a few questionable practices, including the lack of an HVAC vent in the basement bathroom (shown in green ...
2
votes
1answer
72 views

How can I increase the effectiveness of the A/C in a hot 2nd floor converted attic master suite?

Just bought a 1940's masonry construction house. House has a finished basement (cold as a meat locker), first floor (comfortable) and 2nd floor (too hot). The 2nd floor is an attic that has been ...
2
votes
1answer
365 views

central a/c won't cool

My A/C unit was just checked last week- the tech said it had enough freon. Monday we had a nasty storm- electricity flickered, but never went out. After the storm, we noticed the a/c went on, but it ...