Catastrophic compressor failure...need info

[US Iceman]

How much ice build-up is too much build-up?

Where?

On piping with insulation you should never have ice. Ice on insulated pipe shows a failure of the insulation & vapor retarder. Ice on some control or service valves is not a big deal, since these are not usually insulated to allow for easier service.

If a low temperature pipe stays at that low temperature constantly the ice only increases the dead-weight on the pipe and increases the heat load due to parasitic heat gain. If the pipe is cycling through temperatures like a hot gas defrost line will the repeated freeze-thaw cycle can promote increased corrosion rates, if the vapor retarder has failed (and most will or have). Corrosion is the main issue the way I see it.

[bsh3239]

Where?

On piping with insulation you should never have ice. Ice on insulated pipe shows a failure of the insulation & vapor retarder. Ice on some control or service valves is not a big deal, since these are not usually insulated to allow for easier service.

If a low temperature pipe stays at that low temperature constantly the ice only increases the dead-weight on the pipe and increases the heat load due to parasitic heat gain. If the pipe is cycling through temperatures like a hot gas defrost line will the repeated freeze-thaw cycle can promote increased corrosion rates, if the vapor retarder has failed (and most will or have). Corrosion is the main issue the way I see it.

Insulation - that is a given - I always look for water migration into the insulation (vapor barrier leaks). The lesser known stuff is: Pumps - when the pump is completely covered in a thick layer of ice, when an uninsulated line is covered in a layer of ice....In general with these cases - I have been starting to address the ice issue - when there is about an inch depth of ice build - up - mainly due to the added weight of the ice over the system. I will address the valve issue when the ice has completely encased the valve stem - I have even found valves completely encased (stem and handle) in ice. These are no- brainers. The harder cases to evaluate are the pumps and uninsulated lines. I have tried many times to locate literature that would provide guidance on an acceptable level of ice build-up on such items - but I have not been successful.

[US Iceman]

Ice is a fact of life in low temperature systems. Exposed valves will accumulate it, but your suggestion of the ice covering the valve stem is an issue. If you need to close the valve and can''t, that's an issue.

ice on pumps I would not worry about though.