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Author Topic: Fridge, you'll kill us all.... :o)  (Read 49968 times)
Heinz
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« on: November 11, 2010, 12:46:59 PM »

Oh god, he's going to kill us all.... Despite the the woman's cry of doom, we are still alive as is the fridge  Grin
couple of days ago the fridge stopped cutting out, ran all the time and didn't cool much. I hate chucking out stuff which is 90% perfect just because one part has failed, seems to be my "calling" to repair machines which others would class as unrepairable or not worth the time.
A modern fridge has no valve for re gassing as the fill pipe is crimped shut in the factory.
I had noticed ages ago in the BES plumbing cat. that the commercial refidgeration fill valves are just shrader tyre valves.  Also I knew from researching ground source heat pumps that propane was a good refidgerant. So despite the womans complaints "why waste time on an old fridge"  and "you'll blow us all up" I took the fridge out to the workshop. Carefully cut off the crimped fill pipe, nothing came out so the gas was gone and my diagnosis was correct.

I got a tyre valve and shaved the rubber off it with a knife, then sanded it clean. sleeved the copper fill pipe to the tyre valve with a bit of 8?mm copper pipe and soft soldered them together.

Screwed in the core and pressurized it with propane, 60psi. I used a propane cylinder with unregulated fitting and the tyre valve connector robbed off my vintage Dunlop footpump. Checked the plumbing for leaks but could find nothing, even cut out a chunk of the insulation so I could check the joint where the high pressure pipe connects to the expansion section. No leaks anywhere that I can find with the soapy water so I can only assume that the leak is VERY small and it may have taken the ten years since we bought the fridge for the gas to leak out. If I have to top it up in another ten years I'll be happy  Cheesy
I emptied the system again and with the aid of a stick, whiskey, digital scales and a chair refilled it with a measured amount of propane.

 The sticker says it should have 24g +- 1g for R600a so I put a smidgen more than this in, bound to lose a wee bit in the pipe and disconnecting the valve. If you just connect the propane cylinder to the fill pipe, only a small amount of gas will flow to the fridge, but as the fill pipe is on the suction side of the compressor, switching on the fridge will suck the propane in  Grin
The fridge now cools very quickly although the thermostat is faulty, even with the end of it covered in ice, still doesn't turn off, Ebay 3.70 for a new one  Grin

Heinz
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Justme
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« Reply #1 on: November 11, 2010, 12:56:32 PM »

Using that lever method to weight the gas will give the wrong amount as half the weight is on the chair.
Unless you took that into account.


Oh whilst the gas is very similar you also need some lube oil in the fridge.
It might still be in there from the old gas & it might not.
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Heinz
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« Reply #2 on: November 11, 2010, 01:04:20 PM »

Using that lever method to weight the gas will give the wrong amount as half the weight is on the chair.
Unless you took that into account.


Oh whilst the gas is very similar you also need some lube oil in the fridge.
It might still be in there from the old gas & it might not.

The weight was too much for the wee scales, which is why I used the stick and put in 15g of gas which is really 30g.

Hadn't considered that it may be low on oil, but would have thought that if the oil had escaped, the leak would be A/ oily and B/ big enough to find???
Cheers,

Heinz
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dhaslam
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« Reply #3 on: November 11, 2010, 01:34:44 PM »

But if the gas escaped before what is going to be different now?
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Heinz
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« Reply #4 on: November 11, 2010, 01:46:37 PM »

But if the gas escaped before what is going to be different now?

Well, I kind of agree, but having failed to find any leakage I think the leak must be very, very small and if it's taken ten years to leak out, then maybe it'll take another ten years to leak out again??? Time will tell... and nothing lost but a couple of hours and a smidgen of propane if it doesn't last. Better to try that than add it to the scrap pile. There's a MOUNTAIN of fridges beside the Perth road, can't remember the road number, but you cross this enormous bridge and look down to see piles and piles of dead fridges. I'd rather avoid adding to that if I can...
Cheers,

Heinz
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Countrypaul
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« Reply #5 on: November 11, 2010, 01:56:26 PM »

If you can't find the leak in the piece that is left, maybe it was in the piece you discarded - ie. the crimp could have been leaky.

Maybe this is a hopelessly optimistic view, but then again someone has to be, and it may reassure SWMBO.

Paul
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solarcycle
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« Reply #6 on: November 11, 2010, 03:14:52 PM »

That fridge mountain is below the Friarton bridge on the A90 to Dundee, its enormous and getting bigger no doubt!
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biff
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« Reply #7 on: November 11, 2010, 03:15:17 PM »

hello heinz,
       i have to say that it looks a bit risky,the propane might leak out and collect in a pool or cloud and maybe during the xmas party go bang,to experiment is great but you have to live with it,( god this is strange coming from me),
     reminds me of a friend,,or kind of a friend who bought a strimmer at the bootfair bout 20yrs ago,the strimmer was running fine but the actual cutting effort was missing,so he bodged a 9" black and decker circular steel disc onto the end with a bolt ,nut and big washer,,,no guard,so he started it up and it began to shake so he gave it the gas and it began to steady up,then the nut and washer fell out on the floor and this thing is doing 90 a few ft from him in his enclosed workshop, the door was closed,and he needed his two hands to hold it steady.he could not ease of the throttle because the vibration would come back,finally he lost his nerve and threw it across the workshop,diving to go out the door, the disc passed inches from his face between him and the half open door,slicing a great chunk out of the door,it then continued to rocket around the inside of the workshop taking chunks out of everything it came in contact with,
    i drove up in my van as he staggered out the door,he was shaking from head to foot and crying,i could not believe the damage ,some cuts were neat and some looked like a target practise.,the disc even took the plaster of the wall in places. and the disc itself,,,,well next to no wear. and himself,?, no damage but badly shaken.
    the moral of the story?? well there are some things you are better to buy new,
 hysteria                                 biff
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rhys
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« Reply #8 on: November 11, 2010, 03:34:45 PM »

Hm and this fridge won't be A++ rated wil it? faint
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Heinz
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« Reply #9 on: November 11, 2010, 04:09:55 PM »

hello heinz,
       i have to say that it looks a bit risky,the propane might leak out and collect in a pool or cloud and maybe during the xmas party go bang,to experiment is great but you have to live with it,( god this is strange coming from me),

I did consider this, but as there are now thousands of fridges made with propane as the refrigerant each year and the amount is so small, I decided it would be fine. I have no way of measuring it, but if my other half is slow to ignite the gas ring on the cooker or one of the kids plays with the cooker controls, how much gas is released into the kitchen??? I did find some rules and regs. bumf on the net which said that the max permitted quantity of propane in a domestic fridge was 150g, presumably to keep the volume low enough to prevent an explosive mix being formed if released into the air contained in an average sized kitchen. 24 to 30g is Heinz-all and if it does leak, it'll be over days/weeks/years, not just released in one "lump". It'll be fine  Grin

Heinz
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Philip R
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« Reply #10 on: November 11, 2010, 04:16:36 PM »

I like your experimentation with the propane gas.  stir

I notice the compressor has an R600a label on it, R600a is isobutane. Maybe some butane would have been a better match for your system. To late now as it seems to be working.

It would seem that propane is fairly compatible with the lube oil used in the older R12 and R22 systems. I have the former still in my kitchen fridge, will one day by a nice A++ device, see the savings and wish I had replaced it sooner!!
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Philip R
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« Reply #11 on: November 11, 2010, 04:19:22 PM »

Apologies for my bad spellings in the previous write up. I used the spell checker but pressed "ignore" instead of  "change". wackoteapot
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johnrae
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« Reply #12 on: November 11, 2010, 06:20:30 PM »

Great thinking and nice work on the fridge.  Sensible application of inovation and common sense.

As for the guy with the strimmer - a clear candidate for the Darwinian award.  When you put what is effectively an unguarded circular saw on the end of a piece of garden equipment ---------

jack
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wookey
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« Reply #13 on: November 11, 2010, 06:25:56 PM »

World-class bodgery. Well done. Interesting to know if efficiency changes significantly. Do you know how much it used before?
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Wookey
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« Reply #14 on: November 11, 2010, 06:46:27 PM »

Great bodgeneering mate, but next time, please do it out doors.

Gas explosions take no prisoners.
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