superheat

[johnson55]

so to avoid confusion i thought i would explain on here and see if you guys agree ,when you take a super heat reading what you are essentially measuring is how much heat the refrigerant is picking up from the outlet of the evaporator to the inlet of the compressor ( the amount of heat added after the refrigerant has boiled off) but i see technicians taking the suction pressure and converting it to temperature and then i see them take a reading of the suction line in near enough the same place as the service port ! this to me is wrong your not measuring the amount of heat picked from outlet of evap to inlet of compressor. Now say for example i take my suction pressure near the inlet of the compressor and convert it to temperature which is r410a -121 psi corresponding to 35 f (meaning that at that point in the suction line my refrigerant at that pressure is 35 f). Now lets say you dont have a service port at the immediate outlet of the evaporator you measure the suction line temp with thermocouple as close to txv bulb as possible making sure its insulated now lets say thats the temperature reading you get is 20f the difference between both temps is 15 f which is your superheat ( the amount of heat picked up after the refrigerant has boiled off between the outlet of the evaporator and the inlet of the compressor. Any comments welcome thankyou

[Coorsman777]

Superheat is measurment between the refrigerant boiling point(Saturated Suction Temp) and the temperature of the refrigerant vapor. Both at the outlet of the evap and the inlet of the compressor you are still taking a superheat reading, just at different points. If you are just taking it at the compressor it may not give you an accurate idea of how your evap is working depending on length of suction line, ambient condition suction line is running through, insulation condition ect...

[Grizzly]

You new guys enjoy your post!

If you bothered to search the topic, you will find numerous previous answers and debaits!

Grizzly

[johnson55]

so my suction pressure corresponding to 35f is the temperature at which it will boil at that given pressure and not the actual temperature of the refrigerant so thats why u take a suction pipe reading? is that what your saying?

[Brian_UK]

Also please try and use the SI system it makes life so much easier for us old folks. ;)

However, having said that, this link being an American product is still in °F.

Have a look at the diagram on page 4 and it should explain things for you.

Download the first document ref no. 10-135

http://sporlanonline.com/literature-and-educational-materials/educational-materials/