Determining Superheat!

[aaronh]

Good evening all, what would you say is the best way to calvulate super heat, here are the two options i thought you could use, i just wanted to know what people thought was the best and mos accurate procedure.

1. Measure suction pressure at TEV bulb location and convert that to temperature using PT chart. Measure actual temperature at bulb location and compare the two, difference is the superheat.

OR

2. Firmly attach 2 thermometer probes one at evap inlet and other as close as possible to tev bulb, the temp difference between the two is the superheat.

What do u think is the best procedure?

[Brian_UK]

No 2 does not measure superheat, it just measures pipe temperatures.

[aaronh]

Thanks very much Brian, I thought the first is a much more accurate way of calculating superheat. Thanks again

[Tesla]

Hi aaronh
Sorry to correct you but neither 1 or 2 are best. I am pedantic about accurate measurement. To calculate correctly you will need to first measure the temp of the refrigerant directly using a superheat calculation kit (yellow jacket ritchie) at the bulb location at the end of the cycle (and monitor during the cycle). Also check manufacturers compressor manual which sometimes indicates allowable SH at compressor. You can search this forum for further details.

[taz24]

Hi aaronh
Sorry to correct you but neither 1 or 2 are best. I am pedantic about accurate measurement. To calculate correctly you will need to first measure the temp of the refrigerant directly using a superheat calculation kit (yellow jacket ritchie) at the bulb location at the end of the cycle (and monitor during the cycle). Also check manufacturers compressor manual which sometimes indicates allowable SH at compressor. You can search this forum for further details.

Tesla pedantic or not if I read you correct all you are telling aaronh
to do is what he said in number 1. the only differance between his
way and yours is he is doing using gauges and thermomiter and you
are doing it using a machine.

What the differance??

Cheers taz

.

[nike123]

Tesla is also using manometers but he doesn't measure pipe temperature. Instead, he measure direct gas temperature by inserting tip of termometer inside copper pipe to direct stream of refrigerant gas. That eliminate one portion of transmission diference from gas to copper pipe and than to thermometer.
More precise and faster response.


http://www.yellowjacket.com/HVACRPro...l=7&c=76&p=136

[peyman]

hi aaronh:For example if we have two comp in one circuite and we have unloader how we can detemine super heat?

[NoNickName]

None of you consider the superheat picked up by the suction pipe.
The evaporator SH is the superheat measured on the evaporator outlet. The SSH is the superheat measured on the suction of compressor. It may vary considerably, especially on refrigeration circuit.