Richard, you are absolutely correct about the "counter-intuitive"
direction regarding these valves. The GMC engineers, and/or
technical writers got it wrong too.
I have had my valves apart, and know for sure that the direction
of the arrow is the direction that the valve is designed to STOP
flow. Intuitively, we think that the "flow" is from the
compressor to the bag, but the solenoid valves are not intended
to stop air from leaving the compressor. They are there to stop
air from leaving the bag. Therefore, the arrow should point to
the compressor. In this orientation, the pressure of the air in
the bag assists the valve in closing. In the "original"
orientation, the air pressure in the bag was resisted only by the
spring inside of the solenoid valve. This spring is needed so
that the valve does not need to be installed in a vertical
position.
I suspect that this might sound confusing, and if you want to see
a diagram of the valve, I can send you one off the GMCNet. It
might help with the visualization of the valve design. If your
valves are oriented with the arrow pointing to the bag, it is
quite easy to reverse the layout, and greatly improve their
holding power.
I hope this helps.
Scott Shean
Baton Rouge, LA
78 Royale
>-----Original Message-----
>From: owner-gmcmotorhome
>[mailto
wner-gmcmotorhome]On Behalf
>Of Richard Guthart
>Sent: Wednesday, September 22, 1999 9:18 PM
>To: gmcmotorhome
>Subject: Re: GMC: Air suspension upgrades
>
>
>Scott,
>
>Are you sure the arrow should point toward the compressor?
>
>I ask because this seems counter-intuitive and the
>opposite of other valves
>which (I thought) mark the arrow to point in the
>direction of intended flow.
>This includes the check valve in the Cinnabar upgrade kit.
>
>Please don't get me wrong; I am not challenging your
>statement; I sure am no
>expert. But sure would like confirmation of this before
>we start to tear apart
>the solenoid valves and reverse them.
>
>Richard
>
>> Incidentally, as far as I know, all of the hold solenoids
>> are installed backwards from the factory. Even the manual
>> is incorrect about their installation. (At least they were
>> consistent.) The solenoid valve has an arrow on the side of
>> the body, which should point in the direction that you want
>> the solenoid to "hold". In our application, we want to
>> "hold" air in the bag. Therefore, the arrow should point
>> away from the bag and toward the compressor.......
>
>
direction regarding these valves. The GMC engineers, and/or
technical writers got it wrong too.
I have had my valves apart, and know for sure that the direction
of the arrow is the direction that the valve is designed to STOP
flow. Intuitively, we think that the "flow" is from the
compressor to the bag, but the solenoid valves are not intended
to stop air from leaving the compressor. They are there to stop
air from leaving the bag. Therefore, the arrow should point to
the compressor. In this orientation, the pressure of the air in
the bag assists the valve in closing. In the "original"
orientation, the air pressure in the bag was resisted only by the
spring inside of the solenoid valve. This spring is needed so
that the valve does not need to be installed in a vertical
position.
I suspect that this might sound confusing, and if you want to see
a diagram of the valve, I can send you one off the GMCNet. It
might help with the visualization of the valve design. If your
valves are oriented with the arrow pointing to the bag, it is
quite easy to reverse the layout, and greatly improve their
holding power.
I hope this helps.
Scott Shean
Baton Rouge, LA
78 Royale
>-----Original Message-----
>From: owner-gmcmotorhome
>[mailto
wner-gmcmotorhome]On Behalf>Of Richard Guthart
>Sent: Wednesday, September 22, 1999 9:18 PM
>To: gmcmotorhome
>Subject: Re: GMC: Air suspension upgrades
>
>
>Scott,
>
>Are you sure the arrow should point toward the compressor?
>
>I ask because this seems counter-intuitive and the
>opposite of other valves
>which (I thought) mark the arrow to point in the
>direction of intended flow.
>This includes the check valve in the Cinnabar upgrade kit.
>
>Please don't get me wrong; I am not challenging your
>statement; I sure am no
>expert. But sure would like confirmation of this before
>we start to tear apart
>the solenoid valves and reverse them.
>
>Richard
>
>> Incidentally, as far as I know, all of the hold solenoids
>> are installed backwards from the factory. Even the manual
>> is incorrect about their installation. (At least they were
>> consistent.) The solenoid valve has an arrow on the side of
>> the body, which should point in the direction that you want
>> the solenoid to "hold". In our application, we want to
>> "hold" air in the bag. Therefore, the arrow should point
>> away from the bag and toward the compressor.......
>
>
atrick
