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TTD · 04-30-2018, 07:34 AM

I have a Cummins ISM500 motor, and when I open the access panel, these two connections are attached to the frame rails.

They appear to me to be air lines, and my first guess is it's a way to drain water from them... but I really don't have any basis for that guess.

If it is something to drain water... what is the procedure? Are there more of these somewhere else on the coach I should be doing something with?

BrianGlenn · 04-30-2018, 08:38 AM

They are air lines. But not low point drains from the air tanks. If I remember correctly one is off the top of the rear air tanks used for air bag and one is off the top of the primary air tank for rear brakes.

My air tank drains (off bottom) are located in the middle drivers bay where my wet and secondary tank are located. I also have a tank drain under my entry step for that tank. I have 5 tanks hidden in my 37’ Allure.

They are shown on the pneumatic schematic in my drawing file.

Hope this helps.
Brian

TTD · 04-30-2018, 09:38 AM

OK... I will try to locate the pneumatic drawing for the drains.

So if not drains... the ones in the photo are for what? To actually put air IN for some reason?

Quote:

Originally Posted by BrianGlenn

They are air lines. But not low point drains from the air tanks. If I remember correctly one is off the top of the rear air tanks used for air bag and one is off the top of the primary air tank for rear brakes.

My air tank drains (off bottom) are located in the middle drivers bay where my wet and secondary tank are located. I also have a tank drain under my entry step for that tank. I have 5 tanks hidden in my 37’ Allure.

They are shown on the pneumatic schematic in my drawing file.

Hope this helps.
Brian

TTD · 04-30-2018, 02:57 PM

hmmm... someone else said they are emergency dump valves... I assume for when the HWH system won't release the air?

dons2346 · 04-30-2018, 10:17 PM

They are not emergency dump valves

TTD · 05-01-2018, 12:27 AM

Quote:

Originally Posted by dons2346

They are not emergency dump valves

Any ideas what they are? They seem readily accessible.. Like I should be doing something with them regularly?

BrianGlenn · 05-01-2018, 07:21 AM

I have never had any reason to use mine regularly nor have I completely determined their function. It’s one of those that makes you go “hmmmm”.

I too have surmised that they are to add air for some reason - possibly to add air when needed to tow/move when the engine compressor is inoperable. There was a CC in Tunnel Mountain in Banff last year that needed air added as when they came off the road they lost air while idling waiting to check in for campground. Compressor was pooched and needed air to release service brakes, instead of caging the brakes.

TTD · 05-01-2018, 08:24 AM

Yeah... guess this is like the unmarked toggle switch next to my Gen Start button. It appears to be an aftermarket addon, but I cannot figure out what it does (it definitely is powered as it lights up when I toggle it on)

Downside to buying from a dealership instead of an owner.... can't ask questions about mods. :(

BrianGlenn · 05-01-2018, 09:55 AM

Quote:

Originally Posted by TTD

Yeah... guess this is like the unmarked toggle switch next to my Gen Start button. It appears to be an aftermarket addon, but I cannot figure out what it does (it definitely is powered as it lights up when I toggle it on)

Downside to buying from a dealership instead of an owner.... can't ask questions about mods. :(

I have a boost button next to my gen start in the overhead compartment above the entry door. There were design issues with the size of the gen start battery wire and I regularly have to gang together the chassis batteries to the coach batteries to get start current upped to start generator. The wires were undersized.

TTD · 05-01-2018, 06:21 PM

yeah... this is in addition to the boost button, if I recall.

Guess I'm lucky as my gen fires right up.

As for the hose connections - the CC yahoo group says they are to release air (and water vapor). They don't need to be at the bottom as it's not actual water drops coming out... just moist air.

I opened them each for a second or two, and only felt warm, dry air coming out - so closed them back up.

Guess I'll have to search for the other drains... hoping if I open my generator slide, they'll be in there?