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Posted by Bubba on September 23, 2007, 9:12 pm
wrote:
>Hi:
>
>I'm fairly new to the trade. I am employed by a company that owns 40+
>McDonalds.
>
>I am having an issue with a Bohn/Heathcraft MAC 8G unit.
>
>The original call was for a warm box. When I assessed the system, I quickly
>found that the system was off on the HPCO. I reluctantly hoisted a recovery
>unit on the roof and dropped the head pressure to about 300#. I would have
>gone lower, but the low side pressure was only at 20# (this is a R404
>system).
>
>All went well for about 24 hours. Then I got a call again. This time, the
>head was at about 350# and the suction was in a slight vacuum. The sight
>glass thus far has been full and clear.
>
>I attempted to add some gas. The sight glass on my gauges was indicating
>that gas was transferring, but the head went up very slow and no matter how
>much gas I tried to put in, the suction pressure always went below zero,
>usually very slowly.
>
>I checked the EEV, that was opening and closing. Checked the pressures on
>the other side of filters/driers where possible. There was no difference.
>
>I spoke to our lead technician. he agreed that I checked all that I could
>and it must be the control circuit board in the box. I changed that. No
>difference. Previously I had also changed all four sensors in the box as
>the room temp sensor was giving erratic readings.
>
>Like I said, I'm fairly new to the trade (one year). Anybody have any ideas
>as to what I might be overlooking?
>
>Thanks
>Glenn
>
I know Im going to regret jumping in here but I think we all know me
by now...........muhahaha
First off, I dont have a clue what box you're working on and Ive never
used R-404.
That being said.......
Why would you suck refrigerant out of a unit? Did you check to see any
service record on it prior to when you got there?
When you dropped it to 350 on the head and still had a low suction why
did you button it up and hope it would fix itself?
Then you started adding refrigerant and then found the unit in a
vacuum? What made you think the sight glass was full while running in
a vacuum?
You asked your lead tech and that was the answer he came up with?
WOW! You company must be full of dunderheads. Next time you get a
chance, pull out your sledgehammer and what that dumbshit over the
head with it. I feel for you if you are only a one year tech. You need
some training and so does your company.
Id be interested in checking out your metering device REAL HARD.
Have fun.
Bubba
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