The following questions are from the archives of our emails we get asking questions about air conditioning, heating, boilers, BAS, DDC, and many other questions pertaining to HVAC. We are flooded with emails on a daily basis and it is difficult to answer everyone in a timely manner so we are using the following format to answer as many questions as possible pertaining to HVAC. If you have a question about HVAC and you don't see the the answer posted here please email us and we will do our best to answer your HVAC question in a timely manner.
Ask the HVAC Man Quickpage jump links:
HVAC System On or Off when Unoccupied?
Honeywell Chronotherm Plus 8624D Thermostat Problem
Twinned Split System with a Single Air Handler
Gaffers and Sattler Furnace Blower Motor Issues
Outside Air Free Cooling Economizer System
Goodman Air Conditioner Filter
Air Conditioner to Heat Pump Conversion
Leaking Air from the Air handler and Moisture on an Uninsulated Pipe
Sun Porch and What Type of HVAC System Needed
Saving Money on Heating and Cooling after retirement
Condensation Pipe Leaking Water. Is this Normal?
Hot Water Boiler Reset Control? What is it?
Data Logging Thermostats
1) Question: Is there a thermostat for a nursing home with a print out for temperature verification? There are a few options for you. The answer......
Home Inspector Training and High Performance HVAC
2) Thank you!! I am training to become a home inspector and the info contained on this site is helpfull in identifing issues that require a HVAC professional to resolve. Read more........
Heat Pump Defrost
3) Hi. I noticed my that one of my outside condensing units was laboring throughout the night. This morning I found ice/frost buildup on the radiator fins. I live in Tucson, Az. It has been colder than normal (below freezing) with a bit more moisture in the air than usual as of late. Can you please tell me what causes this frost/ice buildup, and how I go about rectifying? Does this mean that the condensor pump is shot? I'm originally from the midwest, and have never experienced this before. What should I be doing? Thank you for your help. The answer...............
HVAC System On or Off when Unoccupied?
4) Please confirm this advice if you would; it is better to have your thermostat left at 70 to 72 degrees during the day while your home is empty and adjust accordingly when you get home as opposed to shutting off the heater/ac and turning on when you get home. I would think this would put less strain on the unit. Thanks in advance for your help. The answer.......
Learning HVAC Controls
5) I want to learn about BAS and DDC. The answer..........
Honeywell Chronotherm Plus 8624D Thermostat Problem
6) I have a Honeywell Chronotherm Plus 8624D running a Trane XL19i with a Trane XV90 - all installed new in new construction in 2003. Every winter, during the morning warmup from 66 to 70, the burners stays on for approx 1.5 hours at 70, then rises quickly to 73 before finally shutting off. The only way to interrupt the process is to turn the system to OFF at the theromostat. The system is on AUTO with the cooling set at 75 for the winter. I have swapped the thermostats (there are two sets in the house, this is the one in the attic for the second floor) with the same results. I have not swapped the thermostat circut boards, but I can not see a reason to. The main floor is on the same schedule, but has never done this three degree burst. I have had three different contractors out, with correponding charges, with no luck. Have you ever seen this? Any thoughts? Thanks! The answer.............
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Twinned Split System with a Single Air Handler
7) Richard Very nice site! I have a question; my home was fitted out by the previous owner with a twinned system, and a thermostat (Totaline P374-1900) which was not designed to control discreet, paired units. I confirmed this with Totaline. The result is only one unit runs, and the second unit is never activated. It functions, but not automatically. Your website mentioned dual compressors in one system, and mine is similar, two independent compressor/condensers. Seeing the separate condenser units, I first thought the house was zoned, and later discovered both units feed into one Aspen BHA40 4-roll coil. Besides the issue of the wrong thermostat, I'm having problems finding an HVAC person who understands these hybrid systems and will service it. Is this configuration that uncommon? I live very near Houston Texas, so if you know of a local HVAC person with the skills to help me out - let me know. PS - I checked with Honeywell about the possibility of their thermostats working with my setup. They emailed me - they would only work with a HVAC professional. I thought this was strange since they sell them in the hardware stores. The answer.............
Gaffers and Sattler Furnace Blower Motor Issues
8) Hi! I have a Gaffers and Sattler forced air home furnace that needs a new fan motor. Can you answer the following questions please?
1) Do you know how much a replacement fan motor would cost?
2) Can you fax to me the specs on the motor that came with it?
3) Do you sell, or do you know who sells this replacement part?
The Answer........
HVAC Pump Down Method
9) We are in the process of getting estimates to replace our evaporator/blower of a 2 piece unit. When asked about the process out of curiosity the HVAC guy told us since the the system holds pressure and the refrigerant/condensor is new he will just "park" the refrigerant in the compressor, then cut the line to the evaporator, attach the new one and open the the compressor valves to get the system up and running. Is this possible? Can a compressor hold all the refrigerant of an HVAC system? Answer...........
Outside Air Free Cooling Economizer System
10) I'm looking for residental high performance system that uses air intake damper or a multistage (multizone) heating and cooling system similar to what I found at http://www.highperformancehvac.com/ddc_4.html. Any suggestions? Answer...............
Goodman Air Conditioner Filter
11) Looking for a filter to fit a Goodman Air conditioner Model # WMC18-1A. Can you help or give me a name of somebody who can? Also, what kind of filters do you use in your home? Thanks. Answer......
Air Conditioner to Heat Pump Conversion
12) Can I convert my air conditioner into a heat pump? Answer......
Home Humidty Problems
13) HIGH HUMIDITY 60 % +. Within the last month, I moved into a new house. It has dry walls and not plaster walls. The furnace and hot water tank were installed a week or so before we moved in to the house. Last week we determined that there is a humidity issue when the windows were sweating. We are trying to determine the source of the humidity. The contractor feels it may be the high efficiency furnace. I have a Lennox g61mp. The combustion air is pulled from within the un finished basement. Should the air be pulled from the outside? The gases are vented via PVC pipe which slopes back to the furnace.
Could the furnace be causing the humidity problem? If yes, what could be causing the problem. The installer said it is not the furnace. Answer......
Leaking Air from the Air handler and Moisture on an Uninsulated Pipe
14) Dear Richard... my partner and I moved into a brand new mill conversion/rehab condo last year that we absolutely love, but after the summer was over, I went into the utility closet (where the air handler/gas furnace are) and noticed that there was copper corrosion crust/rust that had run down from the air handler (not sure from where, but somewhere fairly high up on the AHU). It had dried up, and didn't seem to be enough to run down the sides of the burner even--no streaks). This winter, though, I noticed that the suction line has a 1/4 inch gap below it (crappy install?), and that warm air was blowing out of it! There is a rubber gasket around it but still an open space around the copper pipe. I'm assuming that in the summer, cold air comes out of the same hole, and condensation must form on the first uninsulated 1/2 inch or so of the suction line, then run down leaving dried up copper oxide on the burner. It's also rusting the bolts on top of the burner. Plausible? How do I deal with the AHU? A little expanding foam? It would have to be replaced every time the panel comes off, though. Should this air be allowed to escape? It seems like a lot of air coming out. Thanks SO much, I have learned a lot from reading your articles! Also, what is a typical donation amount to your website?
How do I deal with the AHU? A little expanding foam? It would have to be replaced every time the panel comes off, though. Should this air be allowed to escape? It seems like a lot of air coming out. Answer......
Sun Porch and What Type of HVAC System Needed
15) We added a 300 sq.ft. of living space to our home as a sun porch. How do we effectively, efficiently heat/cool this space? We've been pitched several options. 1) Use existing with a manual duct damper to the new sun porch. 2) same as above but use a zoned approach w/auto dampers for main house 1st floor and sun porch plus separate thermostats. 3) HVAC with new units for sun porch (e.g., radiate, forced air, etc)
Paramaters.
Sun porch is a 15x20 fully enclosed insulated space with 6 ft. casement windows on three sides. The forth side is the main house wall. Main house is 2 story, 1600 sq ft. per floor, gas heated with 2 Trane furnaces and cooled with 2 Trane central air units. The Trane equipment is new being installed in 2007. Answer......
Ductwork Positioning?
16) I did not see any reference to my question and would appreciate a response as soon as possible, as due to medical situation, have to make a decision soon. We own an OLD house with 13' ceilings in a large part of the home and 11" ceilings in the LV/DR and BR. We are oscillating on where to place the ducts....Floor or ceiling. It appears to be counterproductive to me to put the duct work in the ceiling since it will have so far to go. We are looking for the most cost effective, not upfront cost but operating cost, solution. In addition, we are considering DF heat pumps. The house will need 2 or 3 to be zoned correctly. Please let me know about the duct placement and thank you for your help.
Retired and wants to close off part of the house to save money on heating and cooling
17) I have a Heil gas/electric pkg in my home. I, particularily, want to know, if I can close off a section to save on heating. Heating dealers have not been helpful as they hedge on whether and how this can be done with the system still running at it's most efficient. I have closed doors to seal off area. Then closed floor registers. Should I also close air return in that area? I just read this should not be done at all as it decreases units efficiency? Will you please advise. Thank you.
Condensation Pipe Leaking Water. Is this Normal?
18) We have 2 air conditioning units in our house and 2 pipes protrude from the roof. One of the pipes is dripping water. We were told to look for a blockage and to empty the pans. I don't see where to check for a blockage. Any suggestions?
Hot Water Boiler Reset Control
19) Richard, We are looking at replacing our boiler with a new boiler. The HVAC contractor, I suppose he is the salesman for the HVAC contractor, is trying sell us what he refers to as a rest control for our boiler. He tells us it will save us more money by making our boiler more efficient. I think I understand how it works but my wife is not entirely sure about it. Can you tell us what you think about a boiler reset control and how it works? Thanks and we have learned so much from High Performance HVAC. Keep up the good work. Brent
More answers coming soon...............
20) Interested in data about the economic impact of having a dirty air filter. Can you help refer me? Answer...........
21) I just need to ask how to take the cover off of a 10 seer air conditioner. Just a short step by step method. Thanks. Answer...........
22) I have an consolidated gas furnace in which the igniter glows red but no pilot. If I turn off power and back on it will work. Maybe for a day or two and then it goes back into a lockout mode (per Tech). He has tried to figure the problem out but can't. He thinks the gas valve is the problem. What do I need to do? Answer...........
23) I have a problem in a commercial building with mold. I have had several people look at the problem and offer various suggestions. It seems no one knows the root issue or what is causing it but offers different solutions on fixing the problem. Do you have any suggestions? Answer............
Related HVAC Links
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Air Conditioning Maintenance Page 2 | Air Conditioning Refrigeration System Evacuation | The Most Common Air Conditioning Refrigerant Leaks | Frozen Air Copnditioner Troubleshooting | How Air Conditioners Work | Air Handlers | Condensing Units
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