Heating Help

went back

@ May 4, 2013 7:50 AM in ball buster

about 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.

no

@ May 2, 2013 7:17 AM in subcool

techman 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.

weigh in

@ May 1, 2013 6:01 PM in subcool

If you weigh it in, you will always be right, It doesn't matter if its too hot or too cold.

it was

@ April 30, 2013 1:55 PM in ball buster

about 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.

I don't think so

@ April 30, 2013 7:26 AM in ball buster

once 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.

good idea

@ April 28, 2013 8:50 AM in subcool

Spence 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.

Fujitsu concealed unit

@ April 28, 2013 8:39 AM in Fujitsu concealed unit

Never 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?

piston

@ April 28, 2013 8:34 AM in ball buster

When 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.

that is

@ April 27, 2013 12:50 PM in ball buster

possible, 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

I left the

@ April 27, 2013 9:42 AM in ball buster

nitrogen 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.

hoses

@ April 27, 2013 9:34 AM in vacuum

I actually use 3/8 hoses which work fine. What I meant to post is if you go to youtube and punch in jim bergman evacuation, the guy shows you an evacuation using the valve core tools. They also have a hose set up they use off of the pump that makes things very easy to hook up and use. You don't have to buy the whole evacuation kit they sell, you can build your own kit which I did because I already had some of the stuff.

how to vacuum with core tool

@ April 26, 2013 4:01 PM in vacuum

This is how you evacuate with a core tool. It works great!
[u][color=#0066cc]http://www.trutechtools.com/rapidevac[/color][/u]

I would think

@ April 26, 2013 3:43 PM in ball buster

the pressure would increase as the attic got hotter. But we are talking within 15min. I could see the needle dropping. You must be talking about when I went to lunch and the pessure didn't budge. Still doesn't make sense. Temperature doesn't effect nitrogen pessue that much?

ball buster

@ April 26, 2013 2:20 PM in ball buster

I replaced a R22 condensor.  Before evacuating with service valves closed, I pressure tested the lines and coil with 200 psi nitrogen. It dropped a little within 15 minutes. To make a long story short I couldn't isolate the leak, so I cut the lines at the evaporator, brazed a schraeder valve in and put 200 psi on the evap coil to see if it leaked. And while I was at it, I brazed the suction and liquid lines shut at the evaporator so now back at the condensor with the service valves still shut i could pressure test both lines individually with 200 psi. Here is the ball buster part, I went to lunch and came back, nothing dropped. WTF! Why would it drop when everything was connected, but not when eveything was tested individually? thanks in advance

LRA

@ March 14, 2013 2:38 AM in Running my A/C on a generator...

When sizing a generator, after determining all the general lighting and appliance loads and coming up with the proper KW generator to use, the final step is making sure that the generator you use can handle the starting amps or lock rotor amps of the largest motor load. 95% of the time its the AC. For example - If your calculations say you need a 12kw generator. You then check the LRA of the AC. If A 12kw can handle 63 LRA, and your AC has an LRA of 80, then you would have to go up to the next size generator that could handle 80 or above LRA.

yes

@ February 25, 2013 9:59 AM in yellow stuff

it is natural gas. Is there a little sulfar in the fuel, or in the combustion air?

that's exactly

@ February 25, 2013 8:38 AM in yellow stuff

what I was thinking. 100,000 btu hot air furnace, 40,000 btu water heater. Like I said they are keeping the temp set low at the house because no one is living there. Also, I noticed that the bvent flue goes up the center of the house and terminates through the roof with no cap. There is some fake looking chimney around it made of metal. So i'm thinking cold air is pouring down that pipe and just condensing the gases. Make sense? Why is the condensate yellow? What's in the flue gases that makes water turn yellow? thanks again

yellow stuff

@ February 25, 2013 12:20 AM in yellow stuff

coming out of flue pipe joints. Any ideas on what this could be? A new furnace and water was recently installed in this house. The house was renovated, and hasn't been lived in about 4 months. Heat has been set on 60 degrees because it has been vacant. Thanks.

transformer?

@ December 25, 2012 8:46 AM in no heat

You mentioned you replaced the transformer? why? transformers rarely go bad unless something causes them to go bad, like a short or bad relay coil. If everything is dead, like it sounds like, could be the transformer again because you never found out why it had to be replaced the first time.

trap

@ December 9, 2012 7:31 AM in Leaking condensate from venter motor

If it is internal, then you will probably have to take things apart to get to it. If your not comfortable with that, I would call a professional. As far as new  furnace, I would recommend American Satndard. They are rated #1 in consumer reports. If the furnace is installed properly and maintained, there is no reason why it shouldn't last over 20yrs.

I never

@ December 8, 2012 7:11 AM in Leaking condensate from venter motor

heard of that furnace either, but the trap shouldn't be hard to take off. The manufacturer knows it has to be cleaned and usually makes it easy to take off. The installer may have glued the pipe to it like you said, and maybe wasn't suppose too. If you have the directions to the furnace you could look that up. If it wasn't suppose to be glued, you may have to get a new trap and install it properly so that it is easily accessible in the future.

yes

@ December 7, 2012 7:26 PM in Leaking condensate from venter motor

the trap could be the problem. if it is slightly restricted, water could be backing up and leaking. the colder it is outside, the more the furnace will run and make condensate. The trap and drain lines should be cleaned out anually. How old is the furnace? I'm assuming the has never been cleaned since all the fittings are glued.