Charge R134 without a scale

[Acrisoft]

Hi

I know that a scale can delivery a precise refrigerant charge.

However many of my students cannot afford for a scale.

I would like to improve a technique that I learnt years ago still in R12 times.

How can I charge R134 in a domestic fridge without a scale using only the manometer as a reference ?

Could anybody describe it step by step right after the vacuum step ?

Moises

[AlexG]

Acrisoft, If u can mesure subcooling 5...8K I suppose it is correct. Sorry, I'm not domestic frige specialist...

[charlie patt]

easier ways i find is sweating of suction pipe with a clampmeter testing comp run amps but on a domestic you could charge on a standing pressure or and dont laugh during my junior years mothers bathroom scales they lasted bloody years but not so good on a small difference my lastest set of scales is 1 gram acuracy i think the bathroom scales depended on time of day and no battery to change

[install monkey]

use 1kg bottles and baking scales- rated for 2kg,small,cheap,and light too.

[tonto33]

Get Scales from here >>> http://www.vulkan-lokring.de/fileadmin/lokring/Kataloge/Hausgeraete_und_Kleinkaelte_Bereich/VULKAN_LOKRING_l_Refrigeration_appliances__en_.pdf

[nike123]

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[nike123]

Hi


I would like to improve a technique that I learnt years ago still in R12 times.

How can I charge R134 in a domestic fridge without a scale using only the manometer as a reference ?

Could anybody describe it step by step right after the vacuum step ?

Moises

That is wrong technique and you cannot improve it.
You cannot correctly charge with manometers only. You need thermometers.

According to Danfoss service literature, you should charge to 4-7K of evaporator superheat.

http://i42.tinypic.com/34hvsph.jpg

[nike123]

Acrisoft, If u can mesure subcooling 5...8K I suppose it is correct. Sorry, I'm not domestic frige specialist...

Charging to subcooling is only with TXV systems. Domestics are 99% cappilary tube and charging is done by superheat or by weight.

[spimps]

Can you afford recovery machines,do you have them ?