charging a cap tube no data

[roadking]

whats the best way to charge a capilary system with no data?is it by subcooling?

[Brian_UK]

Yep, sure is; at least then you know that you have liquid at the start of the cap tube.

Providing there aren't any major pressure drops between the condenser and the cap tube.

[Gary]

Assuming there are no airflow problems:

When the refrigerated space is down to design temperature, the subcooling should be no more than 15F and the compressor inlet superheat should be about 20-30F.

[nike123]

whats the best way to charge a capilary system with no data?is it by subcooling?

Some sources said by superheat! I following this source.

[chillyblue]

Assuming there are no airflow problems:

When the refrigerated space is down to design temperature, the subcooling should be no more than 15F and the compressor inlet superheat should be about 20-30F.

Two problems

1 How do you know how much gas to put in to get to the design temperature (it's a bit chicken and egg, which comes first the charge or the design temperature??????????)

2 Most cappillary systems don't have any means of accessing high side pressures, which makes subcooling readings difficult to get.

CB

[Gary]

Two problems

1 How do you know how much gas to put in to get to the design temperature (it's a bit chicken and egg, which comes first the charge or the design temperature??????????)

All you can do is get it in the ballpark and wait.

2 Most cappillary systems don't have any means of accessing high side pressures, which makes subcooling readings difficult to get.

CB

Make a 3 inch cardboard disk. Poke a hole in the center. Hold the cardboard disk up against the center of the condenser fins (don't crush the fins) and insert your temp sensor through the hole. This will give you a pretty fair estimate of condensing temp.

An alternative is to check the temp of the return bends on the end of the condenser (two or three bends from the top)

[chillyblue]

Nice one, thanks Gary.

CB

[Latte]

Two problems



2 Most cappillary systems don't have any means of accessing high side pressures, which makes subcooling readings difficult to get.

CB

Go to NRS/HRP as they have copper driers with 1/4 inlet / capillary outlet with a schraeder connection on it. I use these all the time as when you cut the old one out you can cut the cap tube end off and connect it and use the schraeder connection with youre lines to blow through the system with OFN so as to make sure there are no blockages. If OK the cat the 1/4 end off and fit it to the inlet pipe from the condenser. Not sure of the part numbers and its too cold to go out to the van and get them tonight but the suppliers keep 100's of them at each branch

[The MG Pony]

As others said, and worth repeating: Fire in gas till you hear the cap tube start spraying liquid, you'll notice a sharp drop in temp on the evap plate, at which point let the fridge cool to temp then adjust charge for 20k of super heat.