Author Topic: guage connections on rooftop unit  (Read 539 times)

Offline mattmctree

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guage connections on rooftop unit
« on: May 18, 2017, 07:12:25 AM »
stupid question but im used to working on split ac systems there you attatche the guages as the condenser. ive seen numerous connection point in package rooftop units and am wondering where to connect to take my super heat and subcooling reading and to check system operation. usually there are ports by the compressor on the discharge and asuction line but if i connect my high side guage there and my thermometer 6 inches away i wont be reading subcooling asthe refriferants hasnt gone through the condenser yet. where the heck to i attatch my guages? stupid question but any help would be appreciated.

Offline Porcupinepuffer

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Re: guage connections on rooftop unit
« Reply #1 on: May 20, 2017, 03:12:18 PM »
Never worked on one but would assume you can still attach your high pressure side on a connection port either after the compressor or after the condenser and you should still have the high side pressure almost the same. You should follow to where the metering device is and mount your temperature probe before it to get the subcooling temperature. Connect temperature probe for superheat on the line before it enters the compressor.
How come you're working on a rooftop?

Offline Saturatedpsi

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Re: guage connections on rooftop unit
« Reply #2 on: May 21, 2017, 11:35:39 AM »
Many/most package units are less than service friendly. And as porcupinepuffer noted, you have to connect the gauges to where ever, then find a suitable place for the temp sensors...and that's usually the challenge.  ;D

On some units, I've removed a panel exposing the evaporator coil, which will usually provide access to the liquid and suction lines. Attach the temp sensors, then replace the panel in some fashion so as not to damage sensor wires...better yet, get some wireless stuff, and maybe the Bluetooth magic will pass through the panel. Believe I've managed to do that before.  8..

Unless you just have to have superheat and subcooling, look for service literature that gives "operating curves" for system pressures and ID/OD temps. If the pressures are somewhere close, chances are the charge is OK.  ;)

Offline mattmctree

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Re: guage connections on rooftop unit
« Reply #3 on: June 25, 2017, 06:17:04 PM »
I got my 313d and am now working for a large company and working on my 313a. Thanks for the replies I'm sure it will help