Joined on November 25, 2010
Last Post on November 20, 2013
@ November 20, 2013 12:07 PM in combustion testIs the goal when checking these systems to try and get around 7.5 o2 readings as long as your co readings are low?
I had one yesterday 175,000 btu old slant fin boiler which I thought was way oversized for the house. The gas pressure was 3.25, the o2 was 4.4, stack temp was over 500 degrees and the co was around 15 ppm. This was after I took this thing apart from top to bottom and cleaned real well. No matter what I did with the gas pressure I couldn't get the o2 higher than 5.5. I had the gas pressure down to 3" at one point and the 02 wouldnt climb. The co didn't change that much either. Is this a case where you are talking about where we really wanted to get deep into it we would have to think about changing orifices? If so, where do you start? Or since the co is good, do you just leave it alone?
Im from central jersey by the way. Please let me know if you are ever doing any classes around here. Thanks
@ November 15, 2013 9:16 PM in combustion testYour a partner of Tim's? I would love to come to one of your classes, but it's just too far. I'm about 5 hrs away. It seems like a very good class, wish they had something like that by me, but they never do.
@ November 15, 2013 8:38 PM in combustion testAny good books on combustion that you could recommend?
@ November 15, 2013 7:05 AM in combustion testwould be caused by to big of an orifice, high gas pressure, what else? What would you be looking for if this was your job?
@ November 13, 2013 5:14 PM in combustion testOver firing wouldn't the gas pressure be high? The gas pressure on this unit was right around 3.5". This is an older 80% carrier unit flue temp was 380 degrees.
@ November 12, 2013 3:34 PM in combustion testbecause I know what your talking about when you say the o2 would go up when the blower comes on and more oxygen is introduced into the combustion air, but on this furnace the o2 reading was only 4.7%, and co2 was 9.08%. Co was 312ppm Co air free 402.
@ November 12, 2013 2:06 PM in combustion test9 out of 10 combustion test I do I get co readings under 50ppm. I had a furnace today that had a reading around 375ppm. Everything was clean, burner was nice and blue with no apparent flame impingement, gas pressure good, drafting ok. If there is a slight crack in the heat exchanger, I know this could cause co levels to rise, but why and how. Could someone explain? Thank you.
@ August 5, 2013 11:38 AM in York side discharge unitThink it was easy to tell, but it wasn't.
@ August 5, 2013 7:34 AM in York side discharge unitthat it isn't just me who couldn't find in the directions which way this thing is suppose to go. The only thing I had to go by is the picture in the directions. I called the tech. dept. and the guy told me as long as the clearances are right, it will be ok. Yeak ok, good thing I put it 22" away and not 6" like the directions say it could be. The whole point I even bought this thing was because the conventional unit I was going to use would have blown warm air right in to the bottom of the deck. Basically this thing is doing the same thing because York sucks and can't even write installation instructions right.
@ July 30, 2013 6:20 PM in York side discharge unitAnyone familiar with the York side discharge unit THD model. They are designed for under decks, and places where there isnt much clearance above. I put one in today exactly the way the directions say, and when I turned it on was surprise that the air flow went towards the back instead of the front. Its installed exactly the way the picture in the directions show. I also have a color flyer that shows it installed that way. Is this correct? You would think the air flow would be away from the building. There is 22" clearance off the back of the house.
@ July 26, 2013 6:38 AM in smart phone appsI finally got rid if my flip phone and upgraded to a smart phone. Can anybody recommend any good hvac apps that are helpfull in the field?
@ July 26, 2013 6:35 AM in 20 yr old residential split system AC compressorKeeping your coils and filter clean will help your compressor run longer. You should also make sure of all the following:
tight electrical connections and proper voltage inputs, capacitors are good, proper air flow over evap. coil, proper charge. You may want to install a surge protector for extra protection.
Properly installed compressors (units) should last over 20 years. AC systems now a days get a bad rap because they are initially installed wrong. Good luck, hopefully you get at leat another 5 yrs.
@ May 4, 2013 7:50 AM in ball busterabout 4 days later to finish. All the pressures held. I don't know what caused the pressure to drop that first time I checked before going through these extra steps. The only thing I noticed is when I cut the suction line to start repairing it, I forgot to let the pressure out and a bunch of oil came out. Can oil in a line cause nitrogen to change pressure a little? That is the only thing that I could think of. I got the vacuum down to below 500 microns and it held for 5 minutes, so everything is good to go. Very strange.
@ May 2, 2013 7:17 AM in subcooltechman I'm talking on a new install which is what this post is about. The original ask about charging by subcool on a cold day. Spence mentioned about weighing it in. I agree with him, whether its 60 out or a 100, if you weigh it in you will be right there. Charging with a sight glass went out with the twist brother, plus they are another thing to leak down the road, especially with R410A. They are more for refrigeration jobs, not the high efficiency AC equipment that is out there today.
@ May 1, 2013 6:01 PM in subcoolIf you weigh it in, you will always be right, It doesn't matter if its too hot or too cold.
@ April 30, 2013 1:55 PM in ball busterabout 3 -4 psi drop within about 20 minutes. Im pretty sure i purged the air out but may be I didnt. still nitrogen usually doesnt budge when there isnt a leak, 3 psi in that short amount of time is alot.
@ April 30, 2013 7:26 AM in ball busteronce I noticed it losing charge I refilled and double checked all the gauge connections, plus the gauges are brand new. Going back tomorrow to see if my pressures are still holding, let you know how i make out.
@ April 28, 2013 8:50 AM in subcoolSpence that is a good idea to weigh in the charge on a cold start up. It is so difficult almost impossible to get it right when it is cold out and there is no load on the system. I tried charging a new American Standard system with a TAM7 air handler the other day and a couple of times while the system was running and I went inside to do something, when I went back out the unit was off. I think the freeze sensor on the air handler was kicking it off. However you can not get an accurate subcooling reading when there is no load on the system. Weighing in is a good idea.
@ April 28, 2013 8:39 AM in Fujitsu concealed unitNever put one of these in, but it will work best for this job I'm doing, a small bedroon - bath addition. Directions say to keep the esp. between 0 - .36. There is no blower performance charts that come with the unit, so how do I size the duct work? I guess just go in the middle with using .20 as a starting ASP. and see where that takes me? Anybody have eperience with these units?
@ April 28, 2013 8:34 AM in ball busterWhen I pressure test, I open both sides of my gauges and feed the nitrogen in with the pressure regulator so that it is equal on each side of the valve, however this has a piston as a metering device.
@ April 27, 2013 12:50 PM in ball busterpossible, but I think I did check them with bubbles. Its an American Standard unit, so those valves have been very reliable for me in the past
@ April 27, 2013 9:42 AM in ball busternitrogen charge in the unit and kept the service valves shut. That was a thought I had of maybe the nitrogen was leaking through the service valves back in to the unit, but if that was the case, the same thing would have happened when I did the individual line testing. I put a little over 200 psi in the evaporator, suction line, and liquid line, and not one of them moved. The suc. and liq. lines was one cut about 6 inches off of the evap. coil, I pinched them off and brazed both of them.