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View Full Version : What gives me the sh*ts about refrigeration (rant warning)







paul_h
11-07-2007, 03:25 PM
These days I'm pretty annoyed with refrigeration. What the installers and manufacturers do piss me off. How the hell can a system work properly if it's designed wrong? I'm not talking about an instaler putting together a package or split, I mean units running at a suction pressure of -20C for a fridge.
This is my greatest annoyance in commercial/domestic refrigeration. I just can't understand it, and all my training goes out the window. What am I suposed to do when my training (ambient = t, HP should be u, cabinet temp = v, sp = w, TD = x for that product, set the pressure cut outs for y and z, etc.)
None of it makes any sense anymore.
Nearly every cabinet I've looked at recently had really low SP and s*ity td and superheats, and there's not a damn thing you can do about it, they're designed like that. Goodbye any semblence of humidity control. Is it just here in australia, or just me?
I'm glad I've gone to domestics, at least you don't have to care there, just be a parts swapper when it stops working.
At this moment I'm deciding whether to go into further education (ie some sort of designer eventually), and work for someone else. Or just be the domestic guy until retirement (easy 100k p.a. since no one else here knows their stuff, and lets face it, domestic stuff is pretty crap these days so plenty of work).
One thing I don't want to do is figure out these sh*tty unbalanced cheap commercial systems that can't be made sense of . Is it like this everywhere else?

Peter_1
11-07-2007, 08:57 PM
They design with high DT's because they then can make smaller evaporators (= cheaper)
I think that's the only reason why they're doing it.
But you have a point of course.

paul_h
12-07-2007, 09:59 AM
Yeah, that's exactly why that do it. There's one manufacturer (UK based I think, but they make them here too), that makes commercial refrigeration cabinets that do it for that reason. They have a really long capillary so the r404a runs at -20C for a fridge just to be made cheaper. Meh, I don't really care too much about these capillary systems with the condensor on the cabinet, I just charge refrig by weight when doing a compressor change. Which happens a lot due to high suction temps and compressor heat meaning frequent burn outs.

What annoys me more is remote condensing units. If I have to change a remote unit it never seems to run right even on TXV systems. ie the manufacturer has down the same thing for the cabinet, but if I charge trying to get any decent suction pressure, I'll not come close. I end up charging just by the sightglass, having crap pressures and temperatures because the system can't work at the correct suction and subcooling.

Case in point, a static coil and coldplate cabinet storing meat on 404a. Suction pressure and temp matters to control humdity etc. The only way it ran was a -20 coldplate.
There a cafe chain here all running on 404a for the forced draught refrig cabinets. They all run at 200kpa.
My favourite one was a condensing unit running two cabinets of different sizes and usage (one opened every 2 min, one every 20min). They ran off the same copper lines, no thermostats, just pressure control cut out for the condenser in the ceiling. Try setting up an LP cut out so they both run at the same temp, when the system ran at 130Kpa on r404a. Also the hotter it was in the ceiling the higher the head pressure, which affects the sp.
I've spent hours trying to work out how and why all these different cabinets could be made like this. I got annoyed and thought I might as well throw away my gauges and PT chart, because they seem to be useless for domestic/commercial kitchen stuff these days.

chillin out
14-07-2007, 08:03 PM
LOL... just wait until you get to supermarket stuff. That will really pee you off.

Chillin:):)

paul_h
15-07-2007, 12:22 AM
Not going near them mate. I'm getting my own van and working for myself. Going to make a mint repairing all the busted domestic inverters and fridges for the rest of my career. They're all made horribly unreliable these days, and not many other people in perth know how to fix them.

slingblade
15-07-2007, 12:53 AM
I have seen some sh1te in my time paul and can understand your feelings, however it has to be stated that a career in domestic repairs is difficult in this day and age. A domestic fridge is available to buy in the uk cheaper than i could put a compressor on one. given the disposable nature of just about everything these days the only way to make good money in this game is to be very good at something not a lot of other people are.
99% of what i do is process water chillers and i make good money because i turn up when asked, the likes of train , carry her , and dork with a y. dont bother for at least 3 days resulting in much customer displeasure and more beer money for the quality dedicated smaller company like mine who does actually give a f!!!.

Rant over.

paul_h
15-07-2007, 02:05 AM
I hear you about the prices, but I've been doing the domestic thing for four years now, and people will pay.
Most of the time it's just a sensor or thermostat, and if it is a compressor, they will still get it repaired because insurance covers it. (home contents insurance over here covers motor fusion).
Believe me, we currently do a lot of air con compressor repairs @ $800, even though a brand new unit would be better (a new 5yr warranty), just because of insurance covering it.

edit: Also, the side by side 500+litre fridge that seems popular here is about $1600-2000. Plenty of people won't want to buy a new fridge every 5 years.
I'll do some simple split air con installation too, doing warranty for them now, and the amount of dodgey installations I see here you blow you mind. The customers always say they had to wait a month or two for install, because they couldn't find anyone, and ended up getting joe blow the plumber to do it.
I'll try to get into some shop display cabinets, that's mainly capacitor, relay or condenser fan breakdowns, so easy stuff.
Most of my current work is repairing electronics damaged by power surges (very common here, and just needs a $1 varistor soldered onto the board). Or damage by mice chewing wires, very common here as the city expands outwards into bush land.
Thats the current work I do, charged out at $99 callout fee and $99 an hour labour.

The Red Krawler
22-09-2007, 04:27 AM
The thing that frustrates me the most about refrigeration lately is the amount of half-trained, half-witted people who seem to pass themselves off as refrigeration technicians. Almost without failure, they have the "gift of the gab" and can talk enough utter tripe that they end up convincing the customer they know what they're doing.

Later, when we turn up to repair something thats been an ongoing fault for months, we cop the blame for big repair bills. Why? Because the previous company has talked their way out of any responsiblity for the poor reliability of equipment. And no amount of evidence to the contrary will convince a customer thats been brainwashed that far.

Very frustrating when an honest company, doing honest work, is usually the last resort because these one man bands are able to do the work cheaper and with more "marketing". On the plus side, we usually pick up that customer once we fix it first go. Just depends on how far brainwashed they are.

NB - Not a go at you paul_h for being a one man band ;) Just an observation in general.

taz24
22-09-2007, 11:07 AM
The thing that frustrates me the most about refrigeration lately is the amount of half-trained, half-witted people who seem to pass themselves off as refrigeration technicians.

.


He's been here five mins and he already knows me.:D


Cheers taz.

grump
01-01-2008, 06:28 PM
Marvelous,keep it up,wingingAusies,lets have more complaining from down under ,talk about calling the kettle black.

thermo prince
02-01-2008, 07:36 AM
Paul, keep on going and use these challenges as a learning experience.

Good luck if you decide to go out on your own ; equally I imagine plenty of HVACR employers would be happy to get a tech like you - sadly most of the people I know in A-NZ are in Transport and according to whinging Gravy, our's is a 'dregs of the barrel' bottom end of the trade! ;)

You should do well for yourself because you have a positive mental attitude (most of the time, excepting this particular ranting post :D ) and I enjoy reading your posts here, whether they be in form of query or replying to others.

regards
T-P