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As you know, the dash A/C in a DP has the compressor mounted on the engine but the condenser, dryer, etc, are mounted in the front of the coach, often in proximity to the generator.
Our QSDP has a sticker with the info you may be seeking affixed to the centre of the firewall area above the Genset, adjacent to the A/C dryer and hoses as shown in the photos below:
You also may be able to obtain this info from the coach or chassis manufacturer or a shop that services truck and bus dash A/C units. Hope this helps.