testing fridge

Post by **Louey** » 15 Jul 2008, 16:36

I'm about to stick a RM122 fridge into the van - not sure if I'll put the gas on it.

Anyway - How do I test that it runs off 12v OK - do I just rig it up to a battery for an hour and see how cold it gets?? or is there a more precise method?

Post by **Mr Bean** » 15 Jul 2008, 17:07

Louey wrote:I'm about to stick a RM122 fridge into the van - not sure if I'll put the gas on it.

Anyway - How do I test that it runs off 12v OK - do I just rig it up to a battery for an hour and see how cold it gets?? or is there a more precise method?

Well Louey you could do a quick test by measuring the resistance of the heating element by putting a multimeter across the 12V input terminals. Low single figure of resistance expected. You can also get some feedback quicker by feeling for heat in the nether regions of the fridge a short while after switching on. I would expect some cooling after an hour or two. The real test is ice in the ice box after several hours. Keep it level. That goes for when in use too but if it doesn't cool down it could need regassing. I never managed to get mine done and so bought a new one.
Regards
Ken

Post by **Louey** » 15 Jul 2008, 17:08

thanks Ken - I shall go and stick a beer in it

Post by **scamperman** » 15 Jul 2008, 17:45

You won't get a lot out of a fridge connected to a 12v battery,the 12v is only usable through a relay and designed for when the vehicle is running.Your fridge will deaden a battery far before it begins to freeze down.12v is only designed to maintain the fridge 'frozen down',the idea being you run it on gas or mains before you set off to reach it's temp,then turn to 12v when you set off.
James

Post by **Louey** » 15 Jul 2008, 18:53

scamperman wrote:You won't get a lot out of a fridge connected to a 12v battery,the 12v is only usable through a relay and designed for when the vehicle is running.Your fridge will deaden a battery far before it begins to freeze down.12v is only designed to maintain the fridge 'frozen down',the idea being you run it on gas or mains before you set off to reach it's temp,then turn to 12v when you set off.
James

cheers James, I knew that the 12v is normally run through a relay and not a battery but I just wanted to test the fridge/s before I go through all the effort of fitting it - gotta test it on gas afterwards too

Post by **Tex Ritter** » 16 Jul 2008, 09:12

You can run it off a 12v battery on your test bench, If you are in any doubt just connect a battery charger at the same time...that's the way I check mine when doing a fridge service, it only takes a couple of hours or so to check that the temperature is going down.

TR

Post by **Louey** » 16 Jul 2008, 09:29

thanks-
had to charge the leisure battery up so I can test 12v

just having fun trying to fit the gas fittings to test it on gas too -

Post by **1664** » 16 Jul 2008, 15:47

Or you can measure the in-line current if you have a good suitably rated ammeter - should be just under 10amps I believe.

Post by **lhd** » 16 Jul 2008, 22:13

Low single figure of resistance expected.

I had 2.3 on the 12v but the 240v element didn't register.
I might add these were the ones I took out as I replaced them both just in case.
Does that sound right? and whats happening with the 240 maybe thats why it didn't work.

Post by **Louey** » 17 Jul 2008, 09:35

I've got 2 fridges to choose from - one seems to work OK on 12v, the gas lights and the burner stays on but I left it for an hour and the pipes got hot but the fridge wasn't cool???

Post by **edoh** » 22 Jul 2008, 06:39

how do you run the fridge on mains to get it cool before setting off? through an ordinary household socket and extension? set fridge to 'mains? - i have a zig unit - basic - a leisure battery - a 3 way fridge - electolux - and have only used fridge on sites w a hook up - seems to work ok ish on site -
once charged at home - then set it to 12v on the way? then - as usual setting when hooked up on site?

Post by **edoh** » 22 Jul 2008, 06:40

how do you run the fridge on mains to get it cool before setting off? through an ordinary household socket and extension? set fridge to 'mains? - i have a zig unit - basic - a leisure battery - a 3 way fridge - electolux - and have only used fridge on sites w a hook up - seems to work ok ish on site -
once charged at home - then set it to 12v on the way? then - as usual setting when hooked up on site?

how long would fridge run - off site -just set on 12v - w/out running battery down?

any info appreciated -

Post by **Mocki** » 22 Jul 2008, 17:51

on 12v it will do more than maintain the temp, if all it does is maintain the temp, its not working properly,however if you are expecting it to pull the temp dowm from 24deg c to 2deg c in a hour, dream on, it will need longer than that............

Post by **Louey** » 22 Jul 2008, 19:28

Steve,

I ;left the 12v running for about 3 hours and the ice tray was noticeably cold, I tried the gas later on and it didn't do much after an hour and a half, I'll try it again tomorrow (and the second RM122

)

Post by **Mocki** » 22 Jul 2008, 21:28

you have to make sure its level on gas, the flame only burns vertically, so misses the target if its not level.......

if its cooling on 12v, the liquid is ok, so it must be a blocked jet is its not cooling on gas.......

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