sleepyEDB

Hi Terence and Marc, Thank you both for the quick replies. I'll make sure to mention using the electrical disconnect on the A/C unit to the tech. sleepy

Hi Terence, Thanks for the reply! I'll make sure to show the tech the on-off-on behavior when running the A/C unit. One question on this...it is getting cold quickly here, down to the low 30s overnight, and we had a frost this morning. Is there any problem with running my A/C unit for the tech on Wednesday morning when the temp will probably be in the 30s to 40s? Thanks, sleepy

Hi hausdok, Thanks for the reply, and for corroborating Bill's view on the gas vent. 1. The furnace is located in an unfinished basement. We haven't been through a winter in this house yet, but I'm guessing the basement will be relatively cold in the coming months since we're in Michigan. 2. After taking some rough measurements, the basement is 26 x 31 x 8, so 806sqft and 6,448cuft. 3. There are no exhaust fans or clothes dryers nearby. The laundry is located on the second story. Also, the walls nearest the furnace and water heater are both exterior foundation walls. Thanks, sleepy

Thanks for the reply, Bill! I'll do some research re: condensation in the vent system. Any idea on the start-stop-restart behavior of the central A/C? I know I was a bit vague on that part, but I'd be happy to supply more info if it would be helpful. Thanks again, sleepy

Hello, I am new to the forum and my HVAC knowledge is very limited. While I have already searched for answers and read what I could, please excuse me if anything in the following is naive or a repeat of another thread. Also, if it is better to split this thread into several different threads with single topics, please let me know. A bit of info: My wife and I moved in to our house in May of this year. We have central A/C in the house and it works well, save for one bit of odd behavior: When using the central A/C, the furnace will kick on the fan for a few seconds, then quickly stop/re-start, and then run without further interruption. We changed out the old manual-dial thermostat for a programmable digital Honeywell. I have recently tested the furnace on the "heat" program and it seemed to function properly. Our inspector noticed a couple of things with the furnace. The first is the presence of corrosion on the exhaust ductwork leading out of the furnace and into the wall. The second is that the furnace flue on the roof is not tall enough and needs to be extended in order to meet code. Here is a link to an online album since I can't upload photos right now: CLICK ME FOR PICS I have an appointment next week with a local HVAC service company to inspect these issues and perform a general tune-up, but wanted to ask the forum beforehand to prepare for what the tech might have to say. My questions are: What do you think the cause of the corrosion is on the ductwork, and how should it be fixed? Is the only reason to extend the flue on the roof to meet code, or are there performance benefits/other reasons to do so? (I think I've read that a short flue could be the cause of backdrafting and/or corrosion in the liner, if I recall correctly.) Do you think the "start-stop-restart" behavior when running the central air is due to the A/C unit itself, or could it be something with the furnace or new thermostat? This does not happen when running the "heat" program, only the A/C. Do you see any other potential problems in the pictures? Thanks, sleepy