01-30-2017, 10:28 AM
Conceptually, the Valid and HWH systems operate the same when in travel mode: the travel solenoid valves must be the only ones open on the manifolds, the HCV's, height control valves, must be operating correctly, and air pressure must be available to the HCV.
There are two failures that can occur at the solenoid valves; they are not getting the electrical signal to open or they can fail to open when signaled.
There are a couple failures that can occur at the HCV's; they can lose the signal of height (the mechanical connection between the axle and the valve is disconnected), they can not be getting the necessary air supply pressure, or they can mechanically fail internally to the valve.
The question is how you figure out what is going on. My personal preference when multiple components can cause the symptoms I'm experiencing is to find a way to determine the component at fault first and then work to figure out how that component has failed. So in the situation we have here how we we determine whether it is the HCV or the manifold valving that is the problem and do that as simply as possible. Since I have two pressure gauges with attached plastic tubing and connectors, I would mount those gauges on the inlet and outlet to the left rear travel solenoid valve. I would then manually level the coach and note the pressure in the outlet line. I would then manually drop the rear of the coach and then return it to the travel mode. I would then note the pressure on the inlet and outlet sides of the travel solenoid. If the gauges read the same but are low the HCV is the guilty party and I get so spend some quality time under the coach. If the inlet pressure is higher than the outlet pressure then the solenoid valve is where I get to spend my afternoon. This process makes one assumption that I don't verify; that the HCV is getting full air pressure. The odds of that air supply becoming blocked is possible but really really small so I'm comfortable with ignoring it.
There are many paths to solving problems, this is the one that works for me.
There are two failures that can occur at the solenoid valves; they are not getting the electrical signal to open or they can fail to open when signaled.
There are a couple failures that can occur at the HCV's; they can lose the signal of height (the mechanical connection between the axle and the valve is disconnected), they can not be getting the necessary air supply pressure, or they can mechanically fail internally to the valve.
The question is how you figure out what is going on. My personal preference when multiple components can cause the symptoms I'm experiencing is to find a way to determine the component at fault first and then work to figure out how that component has failed. So in the situation we have here how we we determine whether it is the HCV or the manifold valving that is the problem and do that as simply as possible. Since I have two pressure gauges with attached plastic tubing and connectors, I would mount those gauges on the inlet and outlet to the left rear travel solenoid valve. I would then manually level the coach and note the pressure in the outlet line. I would then manually drop the rear of the coach and then return it to the travel mode. I would then note the pressure on the inlet and outlet sides of the travel solenoid. If the gauges read the same but are low the HCV is the guilty party and I get so spend some quality time under the coach. If the inlet pressure is higher than the outlet pressure then the solenoid valve is where I get to spend my afternoon. This process makes one assumption that I don't verify; that the HCV is getting full air pressure. The odds of that air supply becoming blocked is possible but really really small so I'm comfortable with ignoring it.
There are many paths to solving problems, this is the one that works for me.
Jon Kabbe
1993 coach 337 with Civic towed