r407c

[dunny123]

R407c
<HR style="COLOR: #999999" SIZE=1><!-- / icon and title --><!-- message -->Is it true that if you have a leak on a R407c unit,you have to reclaim the gas and put a fresh charge in?I was under the impression that 407 is not diffrent to any r400 gases.Ie charge as a liquid,due to it been a blend.But some one told me today that you cannot add gas to a 407 system,is this true?
{after you have fixed the leak of cause}.
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[Grizzly]

Hi dunny.
The way I understand it is this.
As a blend, when in liquid form all the main components (refrigerants) are mixed together.
These main components have the ability to evaporate at differing temperature / pressure.
Therefore when vapour leaks out, which component is being removed from the mix.
Will depend upon at what temperature / pressure there was at that part of the system when the leak occurred.
Although I suspect you already know that!
In short.
When a leak occurs how much of which main component has been lost is unknown.

Originally the recommendation was to completely remove what is left and recharge with fresh Liquid!
Nowadays it is a bit more confusing,
From what I can tell, the general consensus is.
If system pressures are not to far below the normal.
Top it up!
Generally it seems to work!

Personally I hate the stuff!

It's molecules are 7 to 8 times smaller than the nitrogen we use to check for leaks with. (Empty system only of course)

Grizzly

[taz24]

R407c

<HR style="COLOR: #999999" SIZE=1><!-- / icon and title --><!-- message -->Is it true that if you have a leak on a R407c unit,you have to reclaim the gas and put a fresh charge in?I was under the impression that 407 is not diffrent to any r400 gases.Ie charge as a liquid,due to it been a blend.But some one told me today that you cannot add gas to a 407 system,is this true?
{after you have fixed the leak of cause}.

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By my understanding 407 has a glide of about 6 deg.

I have never topped up a 407c system so can't coment on whether it works well after you do, because I have always pulled it and replaced.

If the Grizz says its ok to top up and he has experienced no probs with it then maybe it is ok. I have topped up 404 but that only has about 1 deg glide.

It does depend on where the leak is.
If it is on the liquid line or the suction then you loose the refrigerant as a full mix. You only loose part of the refrigerant if the leak is somwhere were the charge is mid phase, such as middle of cond,evap or on an air cond unit on the saturated liquid line.

taz.

.

[Grizzly]

Taz.
It was not me who changed the format.
Topping up a system is in line with the latest instructions / guidelines. I think it was
posted by the Institute of Refrigeration.
I will try and find the relevant paper.
Grizzly.

Taz I will need to get back to you on this one, can't seem to find the paper I was refering too.

Got me thinking, this has now. It's got me re-questioning that, that I had come to accept as the norm now.
Don't forget I am talking generally about systems with say, 70 -80 KGS of refrigerant.
It certainly makes for an expensive option to always reclaim and recharge!
Cheers for now Grizzly

[taz24]

Taz.
It was not me who changed the format.
Topping up a system is in line with the latest instructions / guidelines.
Posted by the Institute of Refrigeration.
I will try and find the relevant paper.
Grizzly.


Oh right.

I did not know that.

See you learn somthing every day ;)

Cheers taz.

.

[Grizzly]

Oh right.

I did not know that.

See you learn somthing every day ;)

Cheers taz.

.
taz.
Please refer to the addendum I have added to my post above yours!
We must have both been responding at the same time!
Grizzly

[Barbarito]

i got a liebert unit 407c & that case can't add or complete charge on the unit... you need to recover all left on the unit & re-charge with new refrigerant, & is similar pressures than 410a, but be carefull, is really expensive refrigerant & all procedures... recover, vaccum, & new charge... but not imposible... good luck.