Final answer:
The most likely causes for no air pressure at the inlet side of the supply reservoir are a restricted air dryer or a defective automatic discharge valve. These should be inspected and addressed to resolve the air pressure build-up complaint.
Step-by-step explanation:
If you are encountering no air pressure at the inlet side of the supply reservoir while troubleshooting an air pressure build-up complaint, there are a few potential causes to consider:
- A restricted air dryer can cause a blockage in the system, preventing air from flowing into the reservoir.
- Governor setting too high may not be the issue; this typically affects the maximum pressure rather than the flow into the reservoir.
- An empty alcohol evaporator is usually part of the air dryer system to prevent freezing and may not have a direct impact on air flow.
- A defective automatic discharge valve can also prevent air from filling the reservoir as it can be stuck in the 'open' position, releasing air that should be entering the reservoir.
In this scenario, the most likely culprits are a restricted air dryer or a defective automatic discharge valve. These components should be checked and repaired or replaced as necessary to restore proper airflow to the supply reservoir.