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11-08-2013, 08:50 PM #1
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Mycom screw no oil pump for 3 hours
What do you think?
A Mycom screw on NH3 -10sst +35 sct control system failure allowing it to run for 3 hrs with no oil pump.
Safeties would not shut system down due to faulty control relay.
Machine free to turn over & seems to run OK.
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11-08-2013, 11:31 PM #2
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Re: Mycom screw no oil pump for 3 hours
How about this one.
Guy on site wasn't wearing his glasses, pushed a bunch of buttons on the VSD to get the thing running, he succeeded - Manual ON but without condenser fans (thermosyphon oil cooling)...
Ran all weekend, discharge temperature went off the dial at over +150°C & oil turned black.
When the guys inspected the screw (Mycom 250) they needn't have bothered, it was fine inside.
Forgot to say, no oil pump either..Last edited by HVACRsaurus; 11-08-2013 at 11:33 PM.
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12-08-2013, 09:01 PM #3
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Re: Mycom screw no oil pump for 3 hours
Mycom's can be destroyed, but you really have to try, apparently!
Originally Posted by HVACRsaurus
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15-08-2013, 12:17 PM #4
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Re: Mycom screw no oil pump for 3 hours
I spoke to Jerry at Mycom in Selma, Texas. He purposely tried to destroy one for R&D purposes. The machine finally packed it in at 7 psi oil pressure but what he found was, he had to throttle the oil valves to accomplish this. The differential pressure across the package provided enough oil pressure to keep the compressor running.
This test was performed when they were designing the new screw packages with pre lube or no oil pump at all.
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15-08-2013, 01:09 PM #5
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Re: Mycom screw no oil pump for 3 hours
Hi, RANGER1
It is possible ... in case of slide bearings there were some oil due to oil DP otherwise I doubt ... with roller bearings even with small oil wouldn't be a problem ... Originally Posted by RANGER1
In the early days of STAL series 80 ... they run compressor for 1/2 hour without oil for test purpose and found out no problems ... info from the test person
Industrial compressors are very rigid machines, but for sure they need lubrication ... and as always there are some extremes
, but better to not investigate how far we can go ...
Best regards, Josip
It's impossible to make anything foolproof because fools are so ingenious...
Don't ever underestimate the power of stupid people when they are in large groups.
Please, don't teach me how to be stupid....
No job is as important as to jeopardize the safety of you or those that you work with.
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15-08-2013, 09:35 PM #6
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Re: Mycom screw no oil pump for 3 hours
Thanks for replies, interesting to know what you can get away with to a certain degree.
Discharge temp transmitter only goes to 100 C but went over that, to what temp do not know?
Still running OK after fault rectified.
