A320 Hot Air Valve

[Airmann]

Hi,

I've recently been studying the A320 Air Con system and noticed something that I need a little clarification with:

On the newer model A320s the entire Air Con system is run by the two ACS controllers. These 2 computers control all the valves/flaps and monitor all temperatures

On the older model A320s control is split between two PACK controllers (which monitor and control only PACK related valves/flaps), and a Zone Controller, which monitors the Trim Air Valves and controls zone temperature.

My question is, in the older model A320 setup, how is the Hot Air valve being controlled. I've looked through the FCOM and I can't seem to find an answer. In the newer model A320s its ACS Controller 1, that's mentioned quite clearly in the CBT and the FCOM. There's no mention of the old setup.

Thanks

[guiones]

First, you are looking at a newer MSN FCOM that describes the system on that MSN.

The temperature regulation on newer A320 series (I believe MSN 4000 +/- on) is as you say by ACS.

On older models it is controlled by a Zone Controller and two Pack Controllers.

You can find it on FCOM DSC-21-10-10 P1/4

[Airmann]

@guiones I have the LPC FCOM so I can switch between FCOMs for different aircraft, my company has both new and old MSN A320s, so I can view aircraft specific FCOM, but I still couldn't find an answer for my question even in the Old MSN FCOM, that why I asked

@Imperial Shifter: So you're saying that yes the Zone controller does have control over the Hot Air Valve/Trim Air Pressure Regulating Valve?
In that Case the Zone Controller does the same job as the ACS with regards that specific Valve?

The reason I ask is because there are two detailed schematics in the FCOM, one for the new ACS system and one for the old PACK/Zone Controller System. In the New system schematic there is a line connecting the Hot Air Valve to ACS 1, indicating direct control of that valve by the computer.
In the old system schematic there is no line between the Hot Air/Trim Air Pressure Regulating Valve and any computer. There are lines connecting the Trim Air valves to the Zone controller, but nothing connects to the Trim Air Pressure Regulating valve. Is the schematic incomplete?

[IFixPlanes]

@ imperial shifter:
Please do not mix up TAPRV (Trim Air Pressure Regulating Valve) and TAV (Trim Air Valve).

With the TAPRV you get air in the hot air system. The valve is not regulated by the zone controller (or ACSC 1). The controller can (simply said*) only turn it on or off.
The phrase "regulating" belongs to the "pressure". It regulate the hot air manifold pressure to 4 psi above the cabin pressure and this pressure regulation is controlled pneumatically by the valve itself.

Only the TAVs are "regulated" by the controller (ZC or ACSC) to get the wanted temperature in each section.

*) in addition, if duct temp goes above 80 °C, the controller can force a 50% pressure reduction via solenoids.