HVAC Woes
12-30-2003, 07:06 PM
#46
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Dear Rich,
Not ready to give up just yet. Please forget about the evaporator and the front. The hot air comes from the rear into the mixing chamber and is drawn out of the chamber by the blower fan and into the vent system.
You are saying the flow to the pax side or right side is down as compared to the driversa side or left?
Selecting defrost increases the flow but still very uneven correct?
What air is coming out is heated correct?
Is anything coming out of the footwells?
What happens when you select maximum air to the footwells using the slider controls?
What happens when you select max to the windshield and min to the footwells?
Is the flow to the footwells also uneven?
I suspect you have a stuck differential flapper valve inside the air distribution unit or a blockage in there.
When you select defrost can you hear the flapper valves move. You should hear them move after 30 seconds or so as the differential pressure builds up.
Either that or you have a major hot air leak somewhere.
Ciao,
Adrian
964C4
Not ready to give up just yet. Please forget about the evaporator and the front. The hot air comes from the rear into the mixing chamber and is drawn out of the chamber by the blower fan and into the vent system.
You are saying the flow to the pax side or right side is down as compared to the driversa side or left?
Selecting defrost increases the flow but still very uneven correct?
What air is coming out is heated correct?
Is anything coming out of the footwells?
What happens when you select maximum air to the footwells using the slider controls?
What happens when you select max to the windshield and min to the footwells?
Is the flow to the footwells also uneven?
I suspect you have a stuck differential flapper valve inside the air distribution unit or a blockage in there.
When you select defrost can you hear the flapper valves move. You should hear them move after 30 seconds or so as the differential pressure builds up.
Either that or you have a major hot air leak somewhere.
Ciao,
Adrian
964C4
12-31-2003, 07:05 PM
#47
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Adrian,
The driver's (left) side is significantly down compared to the passenger's (right) side.
Selecting defrost boosts the airflow, but the distribution is remains markedly uneven.
The air is heated when heat is selected. The heat works quite satisfactorily.
Nothing is coming out of the footwell vents, no matter where the slider is selected. I've verified the servo is operating the arm which moves the valve. However, no flow in the footwell.
Max to the windscreen and min to the footwells has been tried repeatedly with no change in air flow.
You've confirmed my suspicions of a stuck differential flapper or a significant blockage (foam coming loose, perhaps). I'm taking it down to the local shop on Friday to put the Bosch tester on it so we might be able to confirm it.
If the left differential is indeed stuck, how does one go about repairing it? Do I take loose the paper tube in the footwell to access the valve?
The driver's (left) side is significantly down compared to the passenger's (right) side.
Selecting defrost boosts the airflow, but the distribution is remains markedly uneven.
The air is heated when heat is selected. The heat works quite satisfactorily.
Nothing is coming out of the footwell vents, no matter where the slider is selected. I've verified the servo is operating the arm which moves the valve. However, no flow in the footwell.
Max to the windscreen and min to the footwells has been tried repeatedly with no change in air flow.
You've confirmed my suspicions of a stuck differential flapper or a significant blockage (foam coming loose, perhaps). I'm taking it down to the local shop on Friday to put the Bosch tester on it so we might be able to confirm it.
If the left differential is indeed stuck, how does one go about repairing it? Do I take loose the paper tube in the footwell to access the valve?
