A/C solenoid valve bypass or solenoid ?
08-19-2011, 04:40 PM
#1
Race Car
Thread Starter
A/C solenoid valve bypass or solenoid ?
80-euro
Just received a replacement solenoid valve "getting hot"; only one used in this 80 for the flapper(s)
The one I received vents to air when off the original one does not one is a solenoid one is called a change over valve.
I am not sure if this is the original one installed in the car but it would seem you would want to keep vacuum on the vacuum solenoids when off, this controls recirculation, heater and center flappers.
I can seal it it vent from the rear of the replacement or should I leave it alone? I have no markings except for the replacement valve nipples are black and point in the opposite direction.
Feedback!!
Just received a replacement solenoid valve "getting hot"; only one used in this 80 for the flapper(s)
The one I received vents to air when off the original one does not one is a solenoid one is called a change over valve.
I am not sure if this is the original one installed in the car but it would seem you would want to keep vacuum on the vacuum solenoids when off, this controls recirculation, heater and center flappers.
I can seal it it vent from the rear of the replacement or should I leave it alone? I have no markings except for the replacement valve nipples are black and point in the opposite direction.
Feedback!!
08-19-2011, 06:36 PM
#2
Electron Wrangler
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I'm not really sure what you are saying... but if it doesn't vent vacuum when electrically off - how does it ever go "off" functionally
Alan
Alan
08-19-2011, 11:14 PM
#3
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More info needed - part no, location, function? there is a solenoid on the cross brace to lift the idle when AC is on. Some call the climate control thing under the dash a vacuum solenoid as it controls which vent/water controls are activated - many coloured small dia vac hoses connected...?
jp 83 Euro S AT 53k
jp 83 Euro S AT 53k
08-20-2011, 06:15 PM
#4
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On the early HVAC where the system was manually operated by vacuum valves in the head unit itself only one solenoid (called change over valve - black) was used. This sits down below the radio in the center console where the later bank of 6 solenoids sit. This seems to be up to 80MY with AC. 80+ with AC had 4 change over valves until the automatic AC was used.
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Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
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928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
08-20-2011, 10:16 PM
#5
Race Car
Thread Starter
Alan may be the one to answer this?
The original with black nipples was heating up when on my bench power supply it went up to 115 Degrees measures about 40 Ohms. When powered it acted as a switch on and off.
The replacement with tan nipples facing opposite direction heated up to 125 degrees. When powered it acted as an switch but when un-powered the air excited from the rear hole of the solenoid.
Me thinks the replacement solenoid is bad, or does it help heat the car in the German winter mimicking the hot water valve. ???
The original with black nipples was heating up when on my bench power supply it went up to 115 Degrees measures about 40 Ohms. When powered it acted as a switch on and off.
The replacement with tan nipples facing opposite direction heated up to 125 degrees. When powered it acted as an switch but when un-powered the air excited from the rear hole of the solenoid.
Me thinks the replacement solenoid is bad, or does it help heat the car in the German winter mimicking the hot water valve. ???
08-21-2011, 01:49 PM
#6
Electron Wrangler
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What is this solenoid controlling? The temp is probably OK (unsurprising - likely normal - though I havent checked).
Think about the typical function of a vacuum solenoid - it switches vacuum to an actuator to cause a movement - e.g. air flap or water valve... when the solenoid goes off you want the vacuum to go off too. if you just have a switch type solenoid vacuum valve and it closes - you still have vacuum on the actuator - and unless it leaks you will always still have vacuum on the actuator...!
Hence when off it must vent the downstream side or the vacuum will never go off...
So if this is the intended function - your original valve has a problem in the vent being plugged. The only time non-vented makes sense is if the valve is used as a flow selector - e.g. switching a vacuum path.
Alan
Think about the typical function of a vacuum solenoid - it switches vacuum to an actuator to cause a movement - e.g. air flap or water valve... when the solenoid goes off you want the vacuum to go off too. if you just have a switch type solenoid vacuum valve and it closes - you still have vacuum on the actuator - and unless it leaks you will always still have vacuum on the actuator...!
Hence when off it must vent the downstream side or the vacuum will never go off...
So if this is the intended function - your original valve has a problem in the vent being plugged. The only time non-vented makes sense is if the valve is used as a flow selector - e.g. switching a vacuum path.
Alan
08-21-2011, 02:20 PM
#7
Race Car
Thread Starter
My main concern is the temperature it seems very high, I can't imagine 6 of these in a new model all cranking out 125 degrees each, you maybe correct it is most likely bad.
From the diagram if it does vent it would open the recirculation when car is off assuming vacuum stays in all the other lines. Since previous years did not have this maybe Porsche wanted fresh air to escape when the car is off venting some heat.
See F in the diagram!
From the diagram if it does vent it would open the recirculation when car is off assuming vacuum stays in all the other lines. Since previous years did not have this maybe Porsche wanted fresh air to escape when the car is off venting some heat.
See F in the diagram!
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08-21-2011, 02:59 PM
#9
Race Car
Thread Starter
Alan,
Sure it makes sense I guess; I was not clear the replacement solenoid was the one was venting from the rear not the original one.
I was not sure if the one in the car was not a replacement since the P.O disconnected and taped the 12v feed to it. But after looking at the diagram again you are correct it would stay on.
Sure it makes sense I guess; I was not clear the replacement solenoid was the one was venting from the rear not the original one.
I was not sure if the one in the car was not a replacement since the P.O disconnected and taped the 12v feed to it. But after looking at the diagram again you are correct it would stay on.
