Mine works
So hating to have all Fuso(s) lump together as having bad AC, weak frames, etc, I decided to test my Fuso's Heating and AC system.
2002 Fuso FG (61,000 miles) 2002 Ford F-250 V10 (54,000 miles)
Both vehicles were within 10 feet of each other during testing and were tested concurrently.
Tests were conducted with an analog probe type temp gauge and a digital IR temp gauge.
Both gauges were check for calibration prior to test against know temperatures (freeze and boiling points of water).
F250's Heating/AC system fan flowed approximately twice the CFM of the Fuso's at maximum fan settings.
The Fuso was designed as a commercial truck, the F-250 was (now) designed as a light truck AND passenger vehicle (comfort).
Both trucks have approximately the same square-inches of front windshield Fuso- 2088sq/in.......F250- 2030 sq/in
All temperatures are in Fahrenheit.
Ambient temperature 69 degrees F.
Altitude 280 Feet above sea level.
Both vehicles in shade.
(A)-analog gauge (IR)-IR gauge
Vent temperature with no fan, cold selected, AC off:.....Fuso-70 (A) 69.8 (IR) ---- F250-70 (A) 70.4 (IR)
Vent temperature with full fan, cold selected, AC off:....Fuso-70 (A) 69.2 (IR) ---- F250-65 (A) 64.8 (IR)
Vent temperature with full fan, full heat, AC off:...........Fuso-129 (A) 128.6 (IR) -- F250-141 (A) 140.6 (IR)
Vent temperature with no fan, after heat cycle:...........Fuso-70 (A) 69.8 (IR) ---- F250-70 (A) 70.2 (IR)
Vent temperature with no fan, cold selected, AC on:.....Fuso-36 (A) 36.4 (IR) ---- F250-32 (A) 32.4 (IR)
Vent temperature with full fan, cold selected, AC on:....Fuso-32 (A) 32.5 (IR) ---- F250-28 (A) 28.2 (IR)
Conclusion – No heat ‘bleed through' on either vehicle from heater core when selected off, even after a heat cycle has been run and allowed to cool.
F-250 performs better in both heating and cooling by about a 10-20% percent. This would be expect do to its design as a ‘confortable' truck with other features such as leather, carpet, entertainment systems etc. Some of this ‘performance' comes from the much higher CFM of the F-250's system fan.
Fuso in above test, far exceeds design specification called out for in the factory service manual