Low side maximum pressure

[mfurze]

Hi guys,

I am relatively new to the industry, having around 5 years experience but do have a good understanding of Refrigeration and how it it all works.

However no matter who I seem to ask they never give me the definitive answer to what I’m after?

I’m basically going through Victoria Universiry in Australia to get my skills assesed, however the questions they are asking I believe I know the answer but nobody is saying that’s the definitive answer, which is what I would need to know.

They are asking, What is the expected maximum pressure the low side may be subjected to? Keep in mind that pressure on the low side is higher when the system is not operating. This would be for both Air Conditioning and Refrigeration

Is this basically determined after you’ve accurately charged the system to the correct weight, then measured the pressure on your gauges after the system is off, or am am I being stupid and missing something here?

I presume maximum pressure the high side would be calculated to 15 degrees over ambient temperature in the condenser?

I just want to be accurate in my answers and have someone that actually understand and discuss my answer with?

I Would greatly appreciate your answers

[Brian_UK]

I would go for maximum standing pressure at 55°C as it could be a simple capillary system with the condenser coil sitting in full sunshine.

[mbc]

Hi

in brief answer in ideal system:
In suction
suction Temp. = room temperature - (6 to 8)
suction Temp. = comes Gage pressure we read on our Gage and look for gas chart .
when your system is working your suction pressure is lower than when your system stopped
when your system stopped your pressure equal with pressure comes from your room temp.

but in condenser
condenser pressure :
Air cold condenser :ambient temperature + (10 to 15 depend on design ) = condenser temp. ( Gage pressure on condenser from gas chart )

when your system stop your discharge pressure comes down because your discharge temp ( condenser temp.) comes to ambient temp.

[RANGER1]

I just think max ambient temperature, because if off can’t get any higher than ambient or room temperature.
If system just turned off, evaporator would have been working & area cool, equalisation occurs.

[mfurze]

Thanks a lot for that! Simple I know, I just wasn’t considering the ambient temperature. I was looking too far into the question I overlooked the basics.

If you haven’t any colleagues to discuss things with, you can easily overlook things!

Stupid Pom is what the usual response is. They even call a flared conduit pipe end a bell end! They didn’t understand why I thought it was funny! :rolleyes:

[RANGER1]

Thanks a lot for that! Simple I know, I just wasn’t considering the ambient temperature. I was looking too far into the question I overlooked the basics.

If you haven’t any colleagues to discuss things with, you can easily overlook things!

Stupid Pom is what the usual response is. They even call a flared conduit pipe end a bell end! They didn’t understand why I thought it was funny! :rolleyes:

Just remind them of Australian cricket team cheating, get some mileage out of that��

[mfurze]

Trust me I have! They can’t handle the banter