Spec on pressures

[10GUAGETIM]

I got a thermo king Md 2 sr with 404a ***** what should hi and low pressure be at idle with ambient temp 80degrees

[cadwaladr]

more info needed,do you mean at half speed or stopped,if its running what temperature is it running at i presume your working in f not c

[charlie patt]

ifs its 80 dc you need a smx at least on that on second thoughts the md would run longer

[cadwaladr]

the comment was in the question,fridgeman i am detective i am not,give me /us all! the facts then it will be easier ,if you have guages that are meant for purpuse the give the user some clues.

[gravy258]

thats + 26c in our world.
roughly 240 head and 42 suction (before the CPR valve) after a defrost.
Could be higher if its high humidity

[10GUAGETIM]

sorry its in fahrenhiet. im a truck mechanic not a clue on this except 134a stuff for the cab . do u charge system on low side and as liquid with unit running

[IRMechanik]

sorry its in fahrenhiet. im a truck mechanic not a clue on this except 134a stuff for the cab . do u charge system on low side and as liquid with unit running


404a is always charged as a liquid. Generally from an empty, vacuumed system you would dump as much liquid in the receiver as it will take (engine off) Sometimes you get lucky and it will take the whole charge but not often. Then you use your manifold to throttle the flow and charge in the low side with the engine running. Engine running high speed cool the ball on the receiver should be up. (you may have to give it 15 minutes or so for the system to stabilize.)

Before you add *****, what's your pressures running? Is the ball up? What's the complaint?

[10GUAGETIM]

404a is always charged as a liquid. Generally from an empty, vacuumed system you would dump as much liquid in the receiver as it will take (engine off) Sometimes you get lucky and it will take the whole charge but not often. Then you use your manifold to throttle the flow and charge in the low side with the engine running. Engine running high speed cool the ball on the receiver should be up. (you may have to give it 15 minutes or so for the system to stabilize.)

Before you add *****, what's your pressures running? Is the ball up? What's the complaint?

its not cold pressures r 20 on low side and 175 on the hi side ball is at bottom of glass . it keep shuttting off when i was charging unit thru low side when running.

[10GUAGETIM]

also do u charge thru the valve on the back off compressor

[IRMechanik]

also do u charge thru the valve on the back off compressor

10407

If you're referring to #9 oil pump gauge access, no. That port is only used for checking compressor oil pressure (which is rare)


its not cold pressures r 20 on low side and 175 on the hi side ball is at bottom of glass . it keep shuttting off when i was charging unit thru low side when running.

definitely pressures are low. Were you able to find a leak in the system? Why was it shutting down? Was it throwing a code?

[cadwaladr]

to be honest,its best to recover the charge,vac out the system overnight and recharge into reciever with the correct weight in liquid form only you should find the correct weight of charge on the data plate of the unit,a good tip is buy a heater made to heat the bottle or pour warm water over the bottle to speed up the process.

[gravy258]

this guy obviously hasn't got a clue, take the fridge to sombody who does.

You don't judge the system being low on charge by pressures or the ball.
20 psi suction is what it should be at the compressor after the CPR valve. A MD II is only a 2 cylinder compressor.
Anything could be wrong with it.

[cadwaladr]

truck air con is what he does so thinks reefers operate the same,big mistake