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taz24
13-10-2006, 07:09 PM
This was a good one.
I was working on a multi compressor pack that had six semi hermetic compressors on it ranging in size from fifteen hp up to fifty hp. The pack was a dual temp compound R22 system. I found it not maintaining the correct back pressure and started looking for the reason. I finaly narrowed the fault down to the fifty hp six cylinder, I did a pump test on it and found it to pump discharge pressure and also pull a vac. When pumped down it evan held the vac and discharge pressures:confused: . I removed the heads and found all pistons intact and all seals and valves intact. I then pushed one of the pistons down into the bore and it rotated lovely. The only trouble was only one other piston moved as well. I found the fault to be four smashed conrods. The thing was though the pistons were still in the bores and were therfore sealing the system so that the comp was working but only at a third cappacity.
Four conrods snapping and the comp still running and pumping:cool:

Cheers taz.

monkey spanners
13-10-2006, 10:45 PM
I had something similar with 3 hp prestcold compressor. The customer was complaining of slow cooling on a DX milk tank. The compressor was running nice and smoothly with no noises, did a pump test and as it pulled down into a vacuum it started to sound like a pneumatic road drill:eek:, it really sounded like it was going to explode! After hidding round the corner for a bit, and it not exploding, i went back and turned it off:D As it went into a vacum the pressure above the broken rod/piston must have pushed it down onto the crank, i've got a piece of the conrod which i plan to make into a keyring:cool:

On the subject of snapped rods, a few years ago an engineer on the same company as me drove his van through a flood and stalled it. On restarting it didn't sound quite right so he came over to where we were working to get a second opinion. Bonnet up, hands on fuelpump rev rev REV, head inches from the engine, no it don't sound right i'd get to the garage if i were you.
About half an hour later we got a call from him asking us to come and pick him up as he'd broken down. He had been sat in a que when he heard a bang and saw an odd looking round thing roll out from under the van. The odd thing turned out to be his oil filter:eek: and you could see straight through the block, the side of the engine was gone, right wher the fuelpump should have been, with a H shaped hole on the other side. Half an hour earlier and i'd prohably be dead or missing an arm:eek:
Darwin at work;)

Cheers Jon

taz24
14-10-2006, 08:30 PM
Half an hour earlier and i'd prohably be dead or missing an arm:eek:
Darwin at work;)

Cheers Jon[/quote]


Yes we do silly things somtimes don't we.

Cheers taz