Re: Dash Air Compressor
Reply #19 –
Bob,
You should always default to the compressor recommendations on oil specs. Being you are not sure what oil was currently used or how much residue oil is left in you system you may consider a system flush. Since I'm been in the refrigeration industry for over 40 years mainly the supermarket and HVAC field I can tell you system cleanliness and correct oils are often overlooked. When I bought my 2001 U320 the dash air didn't work, the compressor was the wrong size (same physical size as the correct one), bad discharge hose. I wish I would've taken an picture of the junk that came out, burnt oil and compressor reed valves, so I believe this dash failed quite frequently. I cut open the existing drier/receiver and it was black and plug, I install a larger drier/receiver mainly because I live in area that gets over 115 degrees, I need to have enough refrigeratant to operate in cooler climates. If you do flush your system you need to replace the oil in the hoses and drier, I used about 1/3 of a quart of oil on mine. A neat trick is to add service valves between the compressor and hose connections. This way you can blend off the pressure on the compressor and on top of the compressor there is a 1/4-20 bolt that you can remove and use a makeshift dipstick to check oil level, Sanden sells one.
Last note, in my system the compressor never shuts off unless the dash t-stat Is satisfied (no suction pressure sw installed) therefore suction pressure at the compressor are lower (mine was about 18-20 lbs) so slow oil return and higher discharge temps seems to be normal.
So far in 115 degree summer I only use the dash air and never needed roof air so Good luck with yours,
Steve