What is this tag on my A/C unit?

[DavidJ]

I have a Climma A/C unit and I'm wondering what this tag means. By coincidence (or not!) there is a bit of felt on the end of the closed pipe (you can just see it) which is the same colour blue.
Surely it's not some magic device which tells me that the coolent is low....how could it possibly do this?
Incidentally the A/C is working fine.
Best left alone methinks but what does it all mean?

 

[david_bagshaw]

probably the low pressure fill point /measuring point.

there will be a high pressure one as well. both are connected to the filling kit and the pressure differential is noted in the fill process, to establish the compressor is working correctly and to put the corrrect charge of gas in the system.

 

[rafiki_]

probably the low pressure fill point /measuring point.

there will be a high pressure one as well. both are connected to the filling kit and the pressure differential is noted in the fill process, to establish the compressor is working correctly and to put the corrrect charge of gas in the system.

Correct.

 

[DavidJ]

Thanks David and Rafiki for your quick and reassuring replies....top job guys!

 

[PaulGooch]

It is the low pressure service point, but there isn't necessarily a high pressure point, not all systems have them.

Correct charge of refrigerant isn't worked out from pressure differential, although that's a good way of seeing that the compressor is working, they system is cycling and the refrigerant charge is something close to correct. The correct method of filling with the appropriate amount of refrigerant is to fill it by weight. Somewhere on the system there should be a label stating the type of refrigerant and the amount, in grams.

[pedant mode] It isn't gas, it's liquid refrigerant [/pedant mode]

 

[DavidJ]

Thanks Paul, next time on the boat I'll have a look for refrigerant info. No need for top up yet but nice to understand these things come the day.

 

[stearman65]

Thanks Paul, next time on the boat I'll have a look for refrigerant info. No need for top up yet but nice to understand these things come the day.

You shouldn't need to top up, if the refrigerant level isn't correct you have a leak. Refrigerant is a multi state gas, at low pressure it is a liquid, going to a vapour through the expansion devise, to a gas in the condenser. (50 year fridge man!!!)
Stearman65

 

[DavidJ]

You shouldn't need to top up, if the refrigerant level isn't correct you have a leak. Refrigerant is a multi state gas, at low pressure it is a liquid, going to a vapour through the expansion devise, to a gas in the condenser. (50 year fridge man!!!)
Stearman65

Thanks, so hopefully it will outlive the boat.

 

[PaulGooch]

You shouldn't need to top up, if the refrigerant level isn't correct you have a leak. Refrigerant is a multi state gas, at low pressure it is a liquid, going to a vapour through the expansion devise, to a gas in the condenser. (50 year fridge man!!!)
Stearman65

Depends on the system, if it's got any seals (like auto air con), R134a escapes without having a "proper" leak. If it's in a truly sealed system, like a domestic fridge, it should stay put.

 

[John100156]

You shouldn't need to top up, if the refrigerant level isn't correct you have a leak. Refrigerant is a multi state gas, at low pressure it is a liquid, going to a vapour through the expansion devise, to a gas in the condenser. (50 year fridge man!!!)
Stearman65

At low pressure it's a liquid?

In an AC system it's liquid at high pressure only when it condenses after heat is removed in the 'condenser' prior to entering the liquid line and expansion device! Which it then passes through and evaporates at low pressure to a gaseous state in the 'evaporator' not condenser.....

 

[stearman65]

Refrigeration System schematic.

This illustrats the complete cycle of refrigerant through a typical system. Most domestic type AC units omit the receiver & extend the liquid line to compensate.
http://www.engineersedge.com/hvac-systems/basic-automotive-ac.htm
Scroll down to the schematic.
Stearman65

 

[John100156]

This illustrats the complete cycle of refrigerant through a typical system. Most domestic type AC units omit the receiver & extend the liquid line to compensate.
http://www.engineersedge.com/hvac-systems/basic-automotive-ac.htm
Scroll down to the schematic.
Stearman65

Yep - precisely as I stated - liquid line is at HP after condenser upto the TEV or expansion device - but we will forgive you faux Pas...!