Hello Andy
Sorry to hear that Sady is sick.
Try reading this information.

ShopForum > Technical Information and Support > Diesel Discussion
Organized MB DIY links post: Climate Control:
Organized MB DIY links

Special attention to thread:
Aux. Water Pump takes out CCU
http://www.peachparts.com/shopforum/diesel-discussion/140870-aux-water-pump-takes-out-ccu.html#post1051832

I do hope it is the mono valve, and not the aux pump toasted your CCU.

__________________
ASE Master Mechanic

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D

https://www.boldegoist.com/