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shaun spencer
21-07-2002, 02:03 PM
i have a supermarket that i commissioned the end of april
it is a hussmann penthouse. R404 30000 sq ft store
since start up have had 2 SORIT's fail one 12 one 15

When these fail it is right after a defrost, they stick, suction stays high - around 70.
replaced them and found the o-ring on the piston mangled.
both were on LT Rack
The SORIT 12 was running at 20 psi, the SORIT 15 at 13 psi
Defrost differential @ 20 psi
Not real fun at 100 AM saturday morn and get the warm ice cream call, drive 1.5 hr to store, then 3 hrs to shop for new valve

anyone seeing this or have any insight

also haves graph showing exactly when this happened (microtherm control on thes racks)

Prof Sporlan
21-07-2002, 03:49 PM
Dan would have some thoughts on this situation, but the first order of business would be to ascertain the cause of the SORIT piston damage which we can assume caused the valve to stick closed following the defrost.

The Prof has seen some control systems cycle the epr continuously instead of allowing them to control as designed... a life cycle test of the valve if you will. But this would not explain significant piston damage, after less than 3 months operation.

If the high pressure line to the SORIT pilot is extremely long, and the hot gas is condensing prior to reaching the pilot, this could cause the valve cycle erratically. But again, one would not expect significant piston damage after 3 months operation.

A photo of the piston might help.

Dan
21-07-2002, 04:10 PM
I recall a batch problem with SORIT 12's around 3 years ago where we had distortions of the O-ring. I cannot recall the reason for it. It was quickly dealt with and did not repeat itself. Perhaps the prof or one of his cohorts has a recollection?

The only other thing that comes to mind is perhaps an unschooled brazer at the Hussmann factory?

It might be prudent to examine a few of the other pistons for indications of distortion or damage to the plastic components. If a pattern shows up indicating overheating, Hussmann should warrant complete rebuild kits.

shaun spencer
21-07-2002, 04:40 PM
the high pressure line to the pilot is not long - is a normal hussmann rack I also dont think it was unschooled brazer at factory - the valves dont look overheated. i have first failed valve at office, second in truck, will take pics when i get to office probably friday before i get there - is 110 km away -
then i will post the pic's
if i get time this week , i will check some of the othere SORITS
Owner of supermarket getting a bit upset and getting advice from her hubby who does demestic AC. never saw a rack before, i invited him to penthouse, wouldnt even come up

shaun spencer
27-07-2002, 02:03 PM
i have picks, cant seem to post them here

anyone know how to do this???

shaun spencer
27-07-2002, 02:04 PM
i guess it did post

shaun spencer
27-07-2002, 02:12 PM
sorit 15

Dan
27-07-2002, 03:05 PM
Hard to say, but I wouldn't rule out overheating on the 12. Can't see anything on the 15. Let's see what the prof thinks.

Prof Sporlan
29-07-2002, 02:53 AM
No doubt the SORIT-12 piston seat had been severely damaged, though it is not clear to the Prof if the damage is strictly mechanical, or if the teflon seat had been weakened by overheating. As Dan mentioned, the SORIT-15 piston image isn't clear enough to make any conclusions.

If any part of the brass has a pinkish color, then one could conclude the piston was overheated.

The Prof will show the SORIT-12 piston image to a couple of his supermarket application engineers. If they have any ideas, he will post them.