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Butte
5th Apr 2007, 12:02
What about this question?

What is the purpose of a mixing valve in an air conditioning system?

This question has alternative 3 as the correct, canīt alternative 4 also be correct? If not, are there a mixing valve to both cockpit and cabin?


1Control the supply of hot, cool, and cold air.

2Combine ram air with conditioned air.

3To maintain the selected cabin temperature

4To maintain the selected temperature in cabin and cockpit

Jet II
5th Apr 2007, 20:35
Its not a particularly good question.

The mix valve contols to the lowest selected temperature - bleed valves then 'up' the various zones to the temp selected in those zones.

But then these questions rarely are accurate for all types of aircraft.

Butte
6th Apr 2007, 08:07
..in a textbook they states that this mixingvalve only is connected for mixing air for cabin, it doesnīt say anything about if the mixing valve also mixes the air to the cockpit.

Anyone who knows how it is with this?? Really need to know!!

Empty Cruise
6th Apr 2007, 10:01
2 mix valves, one per pack. One pack typically will supply the flightdeck, with the excess air going to the mix manifold, where it is mixed with the air from the orther pack and is then routed to the cabin.

The reason option 4) is incorrect is the wording "...selected temperature in cabin and cockpit. Each mix valve modulates to maintain the temperature selected for the area it supplies, i.e. on a 73 left mix valve control F/D temperature, and right mix valve controls cabin temperature.

If the wording had been "...selected temperature in cabin or cockpit, option 4 would have been correct as well.

JAA CQB, u gotta love it!

Butte
6th Apr 2007, 13:32
..anyone who know where I can find a schedule for a aircondition system i.e B737?

Phil Hudson
6th Apr 2007, 15:03
.anyone who know where I can find a schedule for a aircondition system i.e B737?

http://www.b737.org.uk/airconditioning.htm :ok:

mainwheel
6th Apr 2007, 17:14
Answer 1.

Especially if it's a B727.

RTFQ as well, the purpose! Not the system, the component. It mixes air.

Question should be struck. Ambigous, Ambiguos.:)