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Wrong regulator in Marathon generator bay
As many Marathon owners open their generator bay the SMC air regulator is set at suggested 20-25 lbs. This is the ideal pressure to support the four (4) mini air bags. Air supply comes from Marathon AUX air side and usually from the Thomas compressor mounted on your 20KW generator.
In order to maintain this 20-25 psi an SMC adjustable valve with pressure gauge located in the generator bay is installed by Marathon.
All is good unless you have the wrong SMC valve installed. Correct application calls for a heat relieving valve.
This special valve will maintain the dialed pressure when generator runs inside a closed bay door.
In my case someone has installed a NON heat relieving valve. This causes the air pressure to increase when generator runs thus pushing air pressure psi way past normal levels.
Above shows the SMC valve wrong part number someone has installed in my generator bay. “NZ” part number says this is a NON heat relieving valve.
Above is the now installed correct SMC manufactured HEAT relieving valve at Marathons suggested air bag pressure.
Part number AR20-NO1H-Z available through E-Bay …price $13-$18 .
Newly installed SMC part number……. dialed pressure will maintain 18psi at all times.
My suggestion is this heat relieving SMC valve should be installed in nearly all generator service with mini air bags to keep correct pressure inside bags prolonging bag life.
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2 Replies
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Al
This interesting, but will have to wait a few weeks to check. ,our coach is in Indio, and we are home. However, on our genset on 0593, there is a Marathon sticker near genset air valve to maintain 30psi. Your newer coach may have different genset weights or something. If we were to put 18 psi in our genset airbags, the heavier side will be almost flat. Do you have a photo to show how inflated your mini airbags are at 18psi?
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Marathon generator bay sticker….2005 XLII is 25 psi
My current 2007 Marathon labeled 20 psi
20 or 25 psi will work. I’ll probably dial up to 20 psi later. Set at 18 psi as sunny side temp of bus will confirm if new SMC valve will / is working correctly. So far works as in tended holding 18 psi checking during sunny day time weather here.
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