Has anyone found a replacement pressure switch for the front six pack that works with the existing electrical plug? I found references to this Honeywell switch (https://www.alliedelec.com/product/honeywell/76578-00000100-01/70111621/) but I don't like how the wire connections are exposed. And at $80/ea I have to imagine there's a cheaper alternative out there. It's just a normally open 10psi switch, right?
The 10 PSI (NC) pressure switches on our (older) '93 U280 did not employ a plug - just two wires secured by screws. I replaced the OEM switches with new identical units sold under the "Hobbs" brand:
Stewart Warner Hobbs Pressure Switch 76578 (https://www.partdeal.com/stewart-warner-hobbs-pressure-switch-10-psi-normally-closed-2-terminal-76578.html)
See Reply #33 and #34 in the thread linked below:
Working On My Six Pack (https://www.foreforums.com/index.php?topic=27491.msg225369#msg225369)
Thanks Chuck. It's not the end of the world if they are exposed I guess. If no one else chimes in I'll give the mothership a call and make sure it's the same on my 01.
Pressure Switch, 10PSI, SPST M/P280S (HPS-10): Pressure Switches | Racetronix (https://www.racetronix.biz/p/pressure-switch-10psi-spst-m-p280s/hps-10) Is this it? Looks like you need a connector to go with it though may be the same as the original?
Got my 10 psi NC switch at NAPA. Like chuck mine has screws
76578-00000100-01 Honeywell Industrial Pressure Sensors, 10PSI, 76578-10 (https://avlis-co.com/76578-00000100-01-industrial-pressure-sensors-10psi-76578-10/)
You could use liquid electric tape to cover the connectors.
When replacing these 10 PSI switches, be sure to verify for your coach whether the switch is NC or NO. They can look identical. If you purchase the wrong "type" switch, it will not function correctly.
Chuck, is there somewhere either on the existing switch or in a schematic that would tell you NO or NC? Or a way to tell by function? Six pack rebuilds are on my back burner list of things to do...
If you are lucky, there would be some kind of marking on the old switch to indicate "type". I'm usually not lucky...
The image below is page 10 from the HWH Leveling System Textbook. It describes the function of the two 10 PSI switches on the front 6-pack manifold. See the paragraph at the bottom left corner of the page.
When the switches are activated by LOW pressure in one side of the manifold, they SEND a ground signal to the leveling system control box. In other words, they
complete a circuit across the two switch terminals when pressure drops below 10 PSI.
You should be able to test this on your coach with your multimeter. With air pressure on your front 6-pack manifold above 10 PSI there should be NO continuity across the two switch wiring terminals (open circuit). When you lower the manifold air pressure below 10 PSI, you should see continuity across the contacts (closed circuit).
Note: The voltage in the circuit is only 12V (or less), so it won't damage your multimeter to test while the circuit is powered.
What is continuity? | Fluke (https://www.fluke.com/en-us/learn/blog/electrical/what-is-continuity)
The pressure switches on mine can be wired for NC or NO. I had to crawl back under the coach and inspect the plugs to confirm and they are indeed wired to be NC.
Here is a post that identifies where I bought replacements
Rebuild-replace 6 packs (http://www.foreforums.com/index.php?topic=41441.msg413546#msg413546)
Zach, not sure how I missed your comment but that does indeed look like a direct replacement. The webpage states only NO but the associated image shows three pins, so I suspect it can be wired NC or NO. Unfortunately they're in Canada and I'd like to get humpty dumpty put back together before this weekend because we have some guests that need our full hookup spot.
These are the replacements that NAPA carries: https://www.napaonline.com/en/p/BK_7011609?impressionRank=1#
They specifically state that the use of thread sealant can interfere with grounding, so it gives me pause. I think it's just a generic warning this company puts on all of their parts and isn't applicable to a simple switch. Anyone concur?
Elliot,
I have yet to do my 6packs, so not 100% sure exactly how these play into that, but a switch is a switch, just need to be sure to get the proper config NO or NC. As for the teflon on the grounding, the switch contacts are internal to the body of the switch, grounding of those would blow a fuse. I could see maybe no teflon if like an oil pressure switch where you are going to ground to close a circuit and tigger a light, but this switch aint that type.
your mainly looking for a much less expensive approach, yes?
Finding the same connector would be by chance. If the 10 PSI is something that must be accurate, also by chance if your lucky.
Here is a simple style we use in our automation systems in my Production plant. This one happens to have a pressure adjustment if that is crucial.
Stainless Steel 1/8 Inches Pneumatic Adjustable Pump Pressure Switch... (https://www.ebay.com/itm/313880845429?_trkparms=ispr%3D1&hash=item4914c19c75:g:uesAAOSwpA1iD51i&amdata=enc%3AAQAGAAAA8KsSHthIwMjeEwegpTiWbPmzVW3oOAxlVkz2H8E6AvyeoUcZY4Lj8aETrisGYH%2Boq5jvJDj1t33tV%2BoFU4kI%2FvLoAg3w29HkLKogNl0FOxv%2BJqOxy9ZFqAzlQh5ecFWTCr2LeBfz2u5mkKDx35z6AYKOhTL7wmwUy%2B%2BegJL44YPA%2F7CNWHn6p1xr7Ybfq2JU01NjlfXmy58iJORTcm4raNAhMUa22mQPn%2FQhwXqHVHf3TSEDgy2r7LYQMfqO07A%2FCaO3S7A6k1UUEtH%2BWqP7gaeKe%2B3Dfeatd%2FLuaouDNyEuwm%2FtRBJSKxjIIZpW0Ttlrw%3D%3D%7Ctkp%3ABFBM1ufRpP9f)
Depends. If the switch grounds through the mounting threads that statement might apply. In the case of the pressure switches on the 6-pack manifolds, I think it does not apply. The switch itself is not "powered" so doesn't matter what it is screwed into. It is purely mechanical. I would use thread paste and not worry about it.