Originally Posted by
bill1983
i have been in the trade for 25 years but didn't start thinking about superheat until 9 or 10 years ago. i don't know how i managed to fix anything and make the repair last.:eek: In commercial refrigeration the emphasis wasn't(and still isnt) on the scientific side of the business, but on how many calls you can do in a day. When i was younger i used to pride myself on doing as many calls as i could. Now i tend to concentrate on properly fixing the 3 or 4 calls i now attend each day.
What made me change?
Well gather round and i'll tell you. :D
It was a chance meeting with a retired engineer who was shopping in the store where i was working. I was having a problem setting a tev in a freezer case. Despite working through a 5 year apprenticeship i couldn't recall ever using eithe a guage or thermometer to set up a tev. I was always tought how to do it with the frost test; that is if the suction line is frosting back to the compressor, then shut the valve in until it stops frosting, then you would be in the right area. and this teaching came from a well respected engineer. The retired engineer (i never found out his name) told me how to measure superheat properly (and what is more impportant why):cool:;); when i saw how simple and obvious it was i was amazed, and began to start questioning all i had been tought. i got as far as i thought i could with logical thought then started buying books. eventually i found this forum and others like it.When you see the kind of questions posted and the depth of knowledge and experience in some of the answers, it must make a lot of engineers realise how little a lot of us know. My advice to any members of this forum is not just to use it to ask questions for your own benefit, but every once in a while flick through the forums to see if anything catched your eye. If it doesn't, select a question at random you never know, something you think you know all about may just be being questioned, and it might just make you think. For those who like me thought they knew enough to do a good job try it somebody elses way for a change; you never know, it might just be better than the way you've been doing it for years.
oh and the question is, if you've never bothered about superheat then how can you tell if the system is efficient, if you have a full refrigerant charge, if the tev is correctly set, if the compressor is receiving the correct amount of superheat to maintain it's cooling, if there is no liquid returning to the compressor, if the evaporator is defrosting correctly, if the controls are correctly set for the systems best and most efficient operation. in these times of energy efficiency drives, anybody who doesn't understand superheat really should ask the question: what kind of engineer do i want to be?
i'm not shooting you down coolhibby because i used to be just like you, but it is time now to start thinking for yourself, use this forum and any other sources that are available to you to begin to become an engineer.
sorry about the length everybody but i thought the point needed to be made