HVAC/R

Page 3 of 4 Previous  1, 2, 3, 4  Next

View previous topic View next topic Go down

Re: HVAC/R

Post by oldgoaly on Fri Nov 08, 2013 9:32 am

silver brazing is harder than regular solder! funny part is I learned to gas weld 1st, then silver braze, had trouble gas welding till I changed style of torch.  heating up the whole joint is the key all has to be hot then your flux flows then the rod needs to be walked around the joint. Don't worry you will get it, then when your in the real world and you can't get to all sides..... ah it is not so easy!!!
avatar
oldgoaly
Member
Member

Number of posts : 100
Registration date : 2012-08-21

Back to top Go down

Re: HVAC/R

Post by tuberadiogeek on Fri Nov 08, 2013 1:30 pm

I found silver brazing easier than soldering. I know that may sound crazy but its true. I've done more good brazes than solders. Either I get it too hot or not hot enough. I'll likely be practicing on my own next month. With brazing I heat up the bottom until its almost red hot then heat the top until its red,then heat both up at the same time. Pull my flame down and back a bit then apply the filler making sure I push it down and get all the way around. I was able to braze as small as 1/4" and as large as 7/8" so I know I will be able to do it well enough next session where it will hold anywhere from a few pounds to over 100 pounds of pressure. Most units in the shop usually run at around 100-150 psi on the high side.
avatar
tuberadiogeek
Member
Member

Number of posts : 665
Age : 35
Registration date : 2013-02-11

Back to top Go down

Re: HVAC/R

Post by oldgoaly on Fri Nov 15, 2013 11:30 pm

well most refer system are going to be silver brazed do to the higher pressures and vibrations from the compressor. Heck you have been doing this for 3 months! I'd say you doing good!  Lately I've been soldering all kinds of odd things like, chocolate candy molds, galvanizes kerosene and water cans, cookie cutters.  cleanliness is next to Godliness!
avatar
oldgoaly
Member
Member

Number of posts : 100
Registration date : 2012-08-21

Back to top Go down

Re: HVAC/R

Post by tuberadiogeek on Fri Nov 15, 2013 11:46 pm

We only had about 2 weeks to learn soldering and brazing. I only ended up with 2 good solders and 9 good brazes. My final grade was a C+. Which is good enough for me. We only learned the basics of refrigeration and refrigeration cycle. I liked brazing much more than soldering and am confident my brazes will hold pressure. The hardest part about the entire brazing/soldering process is we had swage our tubing by hand with swage punches and hammers. On 1/4" he let us use a yoke and block bc there was no way in hell I was going to swage that tiny tubing with a punch style swage. I only hit myself about 10 times with a 1lb ball pein hammer when I would miss the swage. This coming session we get to use an actual swage tool.
avatar
tuberadiogeek
Member
Member

Number of posts : 665
Age : 35
Registration date : 2013-02-11

Back to top Go down

Re: HVAC/R

Post by 75X11 on Sat Nov 16, 2013 12:07 am

It's good they're teaching you to be able to do without. There will be those days.
avatar
75X11
Member
Member

Number of posts : 4900
Age : 61
Registration date : 2013-03-10

Back to top Go down

Re: HVAC/R

Post by tuberadiogeek on Sat Nov 16, 2013 2:05 am

Well we should be using the tool the remainder of schooling. The punch swages were a learning process that was also a time consuming process. Especially when soldering. All we had was emery cloth and brushes for the inside of the tubing which didn't do very good. I had the hardest time out of everyone swaging since I have a bad bicep on my right arm. I likely tore it about a year ago but never seen a specialist only a gp that said it was sprained. It will save so much time using the tool to swage. I have a/c starting Monday. It shouldn't be too difficult since we learned the basics. I'm hoping to get to mainly work with r-22 units over units that use 400 series refrigerants. Since they have to be flashed in the low side. It was bad enough doing around 3 pounds on a freezer and I know some a/c units can hold upwards of 5 pounds.
avatar
tuberadiogeek
Member
Member

Number of posts : 665
Age : 35
Registration date : 2013-02-11

Back to top Go down

Re: HVAC/R

Post by oldgoaly on Sat Nov 23, 2013 5:26 pm

even if it doesn't sink in right away, when you are working on something else....bingo the light goes on!
avatar
oldgoaly
Member
Member

Number of posts : 100
Registration date : 2012-08-21

Back to top Go down

Re: HVAC/R

Post by tuberadiogeek on Thu Nov 28, 2013 2:40 pm

I brazed 2 connections on an ac and they didnt leak, so i can now officially say i can successfully braze. The unit held the required 100psi of nitrogen for an hour. The only part i do not like is waiting on a vacuum pump. Every unit has to be pulled down to 500 microns. Although i am learning, that is for certain. The only thing that is a bit fuzzy still is determining if i'm over or under charged judging by the superheat and subcooling numbers.
avatar
tuberadiogeek
Member
Member

Number of posts : 665
Age : 35
Registration date : 2013-02-11

Back to top Go down

Re: HVAC/R

Post by 75X11 on Thu Nov 28, 2013 4:06 pm

Looks like you are getting along well enough to be as popular as a lottery winner next summer. Smile 
avatar
75X11
Member
Member

Number of posts : 4900
Age : 61
Registration date : 2013-03-10

Back to top Go down

Re: HVAC/R

Post by Dr. Radio on Sun Dec 01, 2013 12:15 pm

I haven't posted to this thread, but I've been following it. I'll chime in now....all I will say is kudos to you for broadening your horizon with an important technical trade!
avatar
Dr. Radio
Member
Member

Number of posts : 937
Age : 37
Registration date : 2012-09-17

Back to top Go down

Re: HVAC/R

Post by tuberadiogeek on Fri Dec 06, 2013 2:37 am

Stuff is finally making more sense. I finally learned the details about superheat and subcooling and roughly what they should be to determine over and undercharge of refrigerant. Also ran into a very odd problem with the condenser fan motor. Upon firing the unit up it started getting around 100 degrees near the condenser and it would run 25-30mins before the high limit switch would trip. We couldn't quite figure out the problem so we were possibly thinking the run cap for the compressor was failing when it got to operating temps which wasn't the problem. While I was searching for a large enough cap my lab partner got my teacher and he figured out that the condenser fan start and run wires were backwards on the cap causing it to run backwards,causing it to overheat. Ive never seen an ac motor run backwards only small dc motors. I have a 12 vdc fan i run on a power supply and i have made it run backwards hooking it up sonce i can never remember what wires are what. We also had to play a bit of guessing game on how much refrigerant to put in it to start with since there was no ID tag. We ended up putting in 12 pounds and it only had just over 5 ft of lineset. It was also an R410a unit,which runs about 3x the pressure of R22.
avatar
tuberadiogeek
Member
Member

Number of posts : 665
Age : 35
Registration date : 2013-02-11

Back to top Go down

Re: HVAC/R

Post by oldgoaly on Sat Dec 07, 2013 11:21 pm

you have only scratch the surface! all kinds of strange thing can make a difference. But you are on the right track. I had a teacher tell us he solved a problem with high head pressure on a set of units at a school by painting the condensers black. He had calculated the black heat radiation effect.... a lot of good that did on a 100 degree day and the sun shining on it, much less the paint acting as an insulator.  Air flow across the coils is so important! inside and out! Don't give up when you get the psychometric chart in and out the wazoo, it can help you solve so hard problems!  I hope they have a set up for air delivery, I worked for Singer Climate Control Division in the test lab / prototype shop. Ran air delivery tests, various fan blades on the same unit, certain blade combos very real picky! a 1/2" difference on the motor shaft could cut the air flow by 30-40%
avatar
oldgoaly
Member
Member

Number of posts : 100
Registration date : 2012-08-21

Back to top Go down

Re: HVAC/R

Post by tuberadiogeek on Sat Dec 14, 2013 12:22 am

We just covered psycometric charts.. They are a royal pain to read, too many flippin lines to follow.. wet&dry bulb,humidity,dew point,grains of moisture and btus.. I can follow one somewhat but its going to take some more time. We also covered delta T. That is also a bit tricky. Next thing we are doing is studying for our MACS certification that will allow us to be section 609 certified. My teacher made a sheet with questions that should be on the test and gave us a study guide. We will do the 608 in about 6 months. The last thing we will cover is ductwork. Then it is on to heating class. We will cover nat & lp gas and fuel oil. I'm thinking i'll be passing with a B, since i averaged C's on homework assignments and B's on all my tests.
avatar
tuberadiogeek
Member
Member

Number of posts : 665
Age : 35
Registration date : 2013-02-11

Back to top Go down

Re: HVAC/R

Post by oldgoaly on Sat Dec 14, 2013 11:57 am

Sometime you will be sitting there with a bucket collecting condensate and using that info to give you a better idea on how well the unit is working. You will get a call "my unit is low on freon" you put the gauges on system is right on the mark for pressures. In and outlet temps are only 5 degrees apart? but condensate is like a river! Sometimes it is as simple as turning off the humidifier in the summer! other times it can be very frustrating telling the "occupants" to close windows and doors!
avatar
oldgoaly
Member
Member

Number of posts : 100
Registration date : 2012-08-21

Back to top Go down

Re: HVAC/R

Post by tuberadiogeek on Fri Jan 10, 2014 8:20 pm

Just a quick update, I averaged a B- the entire AC class, but the post test got the better of me and dropped me down to a C+ which i am happy with. I am now in heating class. Just started yesterday bc of this crazy sub zero weather we had along with the sheets of ice we had for streets. Heating should be a bit easier, but only time will tell.
avatar
tuberadiogeek
Member
Member

Number of posts : 665
Age : 35
Registration date : 2013-02-11

Back to top Go down

Re: HVAC/R

Post by Dr. Radio on Sat Jan 11, 2014 7:38 pm

Good time of the year to learn heating! Very Happy 
avatar
Dr. Radio
Member
Member

Number of posts : 937
Age : 37
Registration date : 2012-09-17

Back to top Go down

Re: HVAC/R

Post by oldgoaly on Sun Jan 19, 2014 4:55 pm

Strive for A+ Cause when a company looks at your grades they will see someone who is always trying to be the their best. Do extra credit if you have the opportunity, it helps make up for something that gives you trouble. Your 2nd year classes will be harder but more like the real world.
avatar
oldgoaly
Member
Member

Number of posts : 100
Registration date : 2012-08-21

Back to top Go down

Re: HVAC/R

Post by tuberadiogeek on Sat Feb 15, 2014 2:38 pm

I strive for the best I can get. Its just not exactly easy. The thing that got me a bit was fuel oil furnaces. I maintained a B the entire course and had 5% of my grade taken away since I missed 1 day when the 24 hour stomach flu hit me like a ton of bricks. This session went pretty smooth since i worked alone the entire time except when it came to fuel oil furnaces since we only had a few up and operational. That was only a few hours. I did everything on a gas furnace alone twice, when everyone was in groups the first time. It was quite interesting running all the gas line and hooking it up. I always knew the concept but never messed with steel piping. The 1st furnace i chose to install was a downflow sitting right on the floor. That was interesting to hook up. So, now I move on to Heat Pumps. Ought to be interesting. I forsee it being very very similar to air conditioning, which I thought was the hardest course of all so far.. Now I know enough to be extremely dangerous.. LOL
avatar
tuberadiogeek
Member
Member

Number of posts : 665
Age : 35
Registration date : 2013-02-11

Back to top Go down

Re: HVAC/R

Post by tuberadiogeek on Wed Mar 26, 2014 8:34 pm

Well, I completed Heat pumps. It wasn't all that bad of a class. I learned a lot in that class. I ended up with a B+.. idk how I managed but I did. Now I move into refrigeration class. I'll get more in depth with refrigeration and freezer units. Shouldn't be too bad of a class. Then I will move into service and procedures 2, where I will learn to change oil in compressors and changing units to different refrigerants and comparing the results to the original refrigerant the unit was designed for. Oh and i'm also EPA section 609 certified.
avatar
tuberadiogeek
Member
Member

Number of posts : 665
Age : 35
Registration date : 2013-02-11

Back to top Go down

Re: HVAC/R

Post by tuberadiogeek on Wed May 07, 2014 8:07 pm

Just finished up refrigeration. Learned alot more about condensers,evaporators and metering devices. Ended with a B. S&P 2 is next. That starts Monday. It is going to be some review of what I have learned this past and some new stuff. Might be a bit of a tough class but nothing too hard.
avatar
tuberadiogeek
Member
Member

Number of posts : 665
Age : 35
Registration date : 2013-02-11

Back to top Go down

Re: HVAC/R

Post by Wildcat445 on Wed May 07, 2014 8:54 pm

This is a good time of the year for refrigeration techs. Especially if you lived in the desert Southwest. I wish you the best in your training.

WC

Wildcat445
Member
Member

Number of posts : 5168
Registration date : 2011-09-19

Back to top Go down

Re: HVAC/R

Post by oldgoaly on Mon May 12, 2014 5:18 am

 cyclops now you know how to keep the beer cold!
avatar
oldgoaly
Member
Member

Number of posts : 100
Registration date : 2012-08-21

Back to top Go down

Re: HVAC/R

Post by tuberadiogeek on Thu Jun 19, 2014 1:37 am

Just finished S&P 2. It was mainly retrofitting from one refrigerant to another. The unit I had was an R404a unit and We retrofitted to R22. IDK why we changed to a more expensive refrigerant but thats what we did. Then he had us change right back to the original. That was interesting. The other main thing we worked on in our spare time was typing up a preventative maintenance/trouble shooting packet. It had to include certain things and if you left those things out points were deducted. Overall it was not too bad. I finished up with a B. Now my last technical class is Special Topics. This is where we have to install every type of unit we had to previously except all on our own. That starts the 30th of this month, since we get a week plus weekends break, which is called "summer break". I will have just under 1 year of classes by the time my last class is over.
avatar
tuberadiogeek
Member
Member

Number of posts : 665
Age : 35
Registration date : 2013-02-11

Back to top Go down

Re: HVAC/R

Post by tuberadiogeek on Mon Nov 24, 2014 7:38 pm

Just wanted to let everyone know that I successfully completed the entire course, including the general education requirements. I completed the the technical classes with B's and C's and general education courses with some D's. The most difficult one was technical math. It was all automotive related and involved some long and multiple calculations. Which were still difficult with a calculator. With all my notes and formula sheets from that class I can basically figure out how to properly rebuild an engine and how to get the correct speed readout when tire sizes are changed. They teach that class to all tech students since they are mainly an automotive school.
avatar
tuberadiogeek
Member
Member

Number of posts : 665
Age : 35
Registration date : 2013-02-11

Back to top Go down

Re: HVAC/R

Post by 75X11 on Mon Nov 24, 2014 7:45 pm

That ought to be valuable knowledge for you. Congratulations!
avatar
75X11
Member
Member

Number of posts : 4900
Age : 61
Registration date : 2013-03-10

Back to top Go down

Re: HVAC/R

Post by Sponsored content


Sponsored content


Back to top Go down

Page 3 of 4 Previous  1, 2, 3, 4  Next

View previous topic View next topic Back to top

- Similar topics

 
Permissions in this forum:
You cannot reply to topics in this forum