Thread: One for the fridgies

Originally Posted by 350RRC

I love this thread.

All the different R....numbers stuff and that is all good.

Why aren't you all up in the Whitsundays where the charter yacht companies and the privates can't get reliable fridge mechs for more than a couple of weeks?

Just asking............

DL

You are joking, right? I'm on the first flight out of Adelaide @ 0600. Have cleaned all the rust off my gear, new gauge lines, Kwells, & I'm gone.

TINY! You ain't kidding Rick, it looks like they were meant for a Display case.

What speed do they run at? Or are they on vector / VFD controls?

Originally Posted by Old Farang

What speed do they run at? Or are they on vector / VFD controls?

These are fixed speed, DOL and I actually can't recall what revs, but a certain large chain are putting all their primary comps on all their racks on VSD's atm. Control is via condenser drop leg temp monitoring and suction pressure. In the past you'd only use a suction pressure transducer. They are deliberately overcondensing these days, which is fine if using EEV's, but most supermarket cases still use TXV's and they hunt or don't modulate correctly if you overcondense. In my experience a thermostatic expansion valve needs a reasonable pressure drop across the valve to modulate correctly. EEV's don't and will maintain superheat at very low pressure drops/condensing temps if they are supplied with a full head of liquid.
Fixed speed Bitzer recips retrofitted with a VSD can generally run up to 65Hz safely. The factory built in VSD versions run up to 70Hz IIRC?
Most of the racks use fixed speed comps that are staged with staged loading/unloading.
We do the same with the big DX air conditioning systems too.

The York screws on that chiller I was talking about a few posts up run up past 105Hz on the VSD!!
All the newer chillers I've had anything to do with run the comps on VSD's and vary the comp speed to load, oh, except one el cheapo Italian chiller that I re-named, eh Des?

Originally Posted by rick130

Yep, recently came across a blast freezer in a kitchen using R452a???!!!

A quick google tells me it's a new R404a replacement.
Thankfully I was only doing a site audit tendering for a new client.

So i wonder what TX was used?Many use a R404a or R22/407c TX,so if its not labelled correctly,well,who really knows whats in it?

And the other issue is the major wholesalers have different gases,that all have similar specs.(that is this new range to replace r404a)

This is all going to be a PITA for the service guys,but as usual,no one gives a rats.

Many of the R404a replacements can't be used on low and medium temp,so now we need two different types of refrigerant to replace the one

Maybe i stock up on r404a before it gets priced out of the market

Paul, I would've said let the big guys (Coles, Woolies) make a choice and run with what they use but atm they are still using cascades with 134a/CO2!
That's what I love about R404, it's so bloody versatile.

I had this discussion with one of the owners of the company I work for a few months back, Dave and Pete are really switched on in this regard, Dave was talking of refrigerants I'd never heard of!!
They both go to Europe at least once a year to the big refrig shows to keep up with the latest tech.

That blast freezer was French, when I checked the pressures I'm guessing it would've used an R404ª valve.

A funny little anecdote.
A number of supermarkets had MT racks with R507 at commissioning.
Guess what they all have now, regardless of labeling?
Every system had R404ª dumped in at each and every top off.
That's what I was advised to do by the service manager from a company that originally installed some of the racks!

All the newer chillers I've had anything to do with run the comps on VSD's and vary the comp speed to load, oh, except one el cheapo Italian chiller that I re-named, eh Des?

You did, & very succinctly too. I still get a laugh when I think about it. ****, see what I mean, I've just ****ed myself?


Geezz Rick, I could never be a budding Fridgie these days with all that is changing & trying to keep up with all this stuff.



The Whitsundays job really does sound enticing, only problem that I can see is the buggers would up anchor & do a moonlight flit once their beer was cold enough & sail off into the Pacific Ocean leaving me out of pocket whilst paying out for a search by an RAAF Orion or a Colins Sub & a Torpedo.

Hell, I do have a vivid imagination don't I?

Save a bit of dosh, Des. Send the Orions to head them off in the Coral Sea.

Thanks 58i, is there a 'Shipping Container Whirlpool' there where Marinised Shonks all get caught up in a huge whirlpool & go around & around & around ad infinitum?

If so, the Orion should be able to locate probably a couple of hundred of them on the list.

Job done.