CoolTech Robinair 34700Z giving headache

[cheloutside]

Off the car pressing recover and waiting a bit the high side gauge slowly rises from 0 and there is pressure in the high side line. Tried it several times, gauge keeps rising. Also when you go into vacuum both gauges show a vacuum but when you go to the high side hose and slowly unscrew it its still full of pressure. Also noticed when filling on a vehicle it wont charge the system unless the vehicle is running and it has to pull the refrigerant into the system. Anyone have a service manual for this unit also?

 

[chris142]

Likely one of the solenoids are leaking. We have the same machine and nobody can fix it. We gave up on Robinair equipment all together. No customer support and constantly breaking down at the worst time.

 

[Azzkker]

I've got a robinair 134a machine and mine had started having the control solenoid that open flow on the lines stick closed under high pressure. If I tap then lightly they unstick. I am planning on replacing all the flow control solenoids this winter season after demand dies down.

Open your side cover and look for the distribution block. There should be multiple solenoids mounted on it. Those are the most likely culprit.

Could also be a clogged filter. When was your last service performed?

 

[cheloutside]

Sorry for the stupid questions I'm going to ask before hand... I had it used and the person before reset everything, the filter said 04/16 and only says 8lbs have gone thru and I bought it 2018 and sat till then and the shop mainly did mechanical work, unless they sucked out some stop leak I'm guessing should be ok, he did say he was having issues with it. I tried tapping all the valves before, no change.
I dont understand how those solenoids are disassembled since I've heard they can be rebuilt? remove the socket head bolt on top, remove the solenoid then the actual valve assembly can be unscrewed is my guess?
Does the storage tank inside the unit have 3 valves on top if I unscrew the hoses, I know the air purge does but does the liquid and the gas side also have a valve built in so I can separate the tank from the hoses.

Im thinking I need to find a manual and take this thing apart piece by piece at this point, the oil injection injects once and stops. The air purge when manually going into the diagnostic test function by pressing 5454 will not purge also

 

[Azzkker]

Best advice I can give you is to ask a couple of your local robinair retailers who the local service provider is, then talk to them for advice.

Luckily one of my big 3 retailers I purchase parts from is a service center for robinair. I can ask them for parts or take them the machine for service if need be.

My current situation with the sticking solenoids was caused by a customer attempted repair with self recharging with the 134a with stop leak. I did not find out about the stop leak stuff till I emptied the oil drain tank and found the goo dripping out with the oil. I changed the oil and filter immediately and purged all lines, but the damage was already done.

 

[cheloutside]

update. The hi and lo side line seals on the hoses where they attached to the machine were swollen(from stop leak I would guess) and randomly collapsing under vacuum or pressure. Replaced them with some short length of unreinforced silicone hose. Recalibrated the scale without tank and calibrated the tank to 0lbs with no refrigerant, works ok so far. The internal tank can have the 3 lines removed even when filled due to internal valves. The main solenoid block I removed from the machine and dissasembled with an allen key, it was free of debris and placed each solenoid on a switch with 120vac and they seemed ok, o-rings werent damaged/swollen etc, so I didnt go any further at this time. Still looking for a service manul though.

 

[RedneckWelder]

I couldn’t find a service manual for ours, and ours is an elderly ************* that won’t stay calibrated no matter how many times the service techs pray over it so I’m always having to come up with workarounds for it.

Id really like to take ours out back and introduce it to my .45.

AC work is frustrating enough but to add the factor of untrustworthy equipment drives me nuts.