Engine Size: 13L Cat
Refrigerant Type: 134a
Country of Origin: New Zealand
Hi there, I've got a problem that I'm sure some of you can advise me on. This 35tonne machine is on tracks (like a digger) and is used in quarries to bore holes in rock so as to
blast the face. It has a 'goldfish bowl' cab,ie glass all round and above, hence the necessity for a/c. I have not worked on it previously, only cars, pickups and trucks. The companys mechanic was on hand to help.
I recovered the remaining refringent out of system, then replaced the r/d. following a lengthy 'vacuum' I got about 650gm af 134a sucked in. This was enough to allow the system to start working, but not yet enough to make cold air. The low side gauge read low, as was expected, but the high side slowly crept up without me adding any refrigerant. It was as if the condencer fan wasn't working. It was. We cleaned out the condencer (low press. water blaster) and was surprised how much crap we washed out. It made a difference, but the 'hi side' still crept up. As if it is over charged. I'm not sure what the charge rate is, but I expect it would be around 1.5kg or there abouts. Some one local suggested perhaps the t/x valve is playing up, but I'm not sure about that.
Your advice would be appreciated. I'm impressed with the quality and amount of info on this forum. Cheers Richie.
What do you call "high"? 200 psi? 375 psi? What sort of ambient temperature? Compressor speed?
Spray some water on the condensor when it "creeps up" If it drops rapidly, you still do not have it clean.
Spray a strong surfactant deep into the fins. I usually use a garden sprayer full of Zep Orange on stuff like that. I don't know what they sell for cleaners down under, but anything citrus based (-limolene will be in the ingredients) or butyl cellosolve based should work well. Some commercial floor strippers are ok on aluminum, check the label.
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.
Thanks for the reply,
I had a hunch the condencer was'nt clean enough, so I degassed and removed it from the machine. There was about 5kg of dirt behind the fan and it's cowling. We cleaned it up and refitted, vacuumed for an hour then regassed. It kicked into life as it should. No more high side 'Hi's' A good result all round. Yer never too old to learn lessons eh. Anyway, machine goes off to work, at the other end of the country in the morning, so it's smiles all round.
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