1977-79 Hotwater Vacuum Switch (Solution)
02-10-2024, 01:35 PM
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1977-79 Hotwater Vacuum Switch (Solution)
I am writing this thread to share the solution to a problem that I was having in the thread below:
https://www.corvetteforum.com/forums...f-valve-3.html
Essentially, there are currently two switches available for the HW Shutoff Valve. One from China with white top, and one with a black top manufactured by Dave Jacobs, who helped me through my problem. The Chinese witch attempts to tackle two tasks with one switch. They’re posted as the wiper door vacuum switch, and hot water vacuum switch. Dave’s is designed for the wiper doors, as well. However, with both switches, retailers list them as compatible in both areas (wiper doors and hot water valve). The problem is that these two functions require different vacuum capabilities. The wiper door vacuum setup switch is designed to hold vacuum and not release it, blocking it entirely so that it does not leak. If you read the copied thread, this was the issue that I had. I was using Dave’s switch, which is a great switch, but listed incorrectly by retailers as the same switch as the Hot Water Vacuum Switch. For the hot water switch, there must be a vent function to allow the hot water valve itself to open and close.
Dave will jump in this thread and better explain, but I wanted to share the intro here.
Some say that they have had success with the “incorrect” listed retailer switches on their 77-79. The truth is, if the vacuum is sealed perfectly with not leaks, these switches should NOT release their vacuum. If they do release their vacuum, then your system likely has a leak that has gone unnoticed.
This thread will hopefully shed light on the issue for others and serve as a helpful resource. Dave was AWESOME! He has worked over the phone with me for the last few weeks to design the appropriate switch from his already existent wiper door switch platform. He can better explain the anatomy of the switch… anyways, thankful to the forum community and all of the useful feedback.
https://www.corvetteforum.com/forums...f-valve-3.html
Essentially, there are currently two switches available for the HW Shutoff Valve. One from China with white top, and one with a black top manufactured by Dave Jacobs, who helped me through my problem. The Chinese witch attempts to tackle two tasks with one switch. They’re posted as the wiper door vacuum switch, and hot water vacuum switch. Dave’s is designed for the wiper doors, as well. However, with both switches, retailers list them as compatible in both areas (wiper doors and hot water valve). The problem is that these two functions require different vacuum capabilities. The wiper door vacuum setup switch is designed to hold vacuum and not release it, blocking it entirely so that it does not leak. If you read the copied thread, this was the issue that I had. I was using Dave’s switch, which is a great switch, but listed incorrectly by retailers as the same switch as the Hot Water Vacuum Switch. For the hot water switch, there must be a vent function to allow the hot water valve itself to open and close.
Dave will jump in this thread and better explain, but I wanted to share the intro here.
Some say that they have had success with the “incorrect” listed retailer switches on their 77-79. The truth is, if the vacuum is sealed perfectly with not leaks, these switches should NOT release their vacuum. If they do release their vacuum, then your system likely has a leak that has gone unnoticed.
This thread will hopefully shed light on the issue for others and serve as a helpful resource. Dave was AWESOME! He has worked over the phone with me for the last few weeks to design the appropriate switch from his already existent wiper door switch platform. He can better explain the anatomy of the switch… anyways, thankful to the forum community and all of the useful feedback.
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interpon (02-11-2024)