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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: plyonsMC9 on May 19, 2021, 07:28:43 AM

Title: MCI-DL345 rear height control valves. Air flow.
Post by: plyonsMC9 on May 19, 2021, 07:28:43 AM

Good morning bus folk!

Received new air leveling valves from MCI, it's a long story. 

My question is; the manual says "Note: Air Pressure Enters Through Check Valve and Passes Out Open Inlet Valve to Bellows".    I've seen other diagrams showing the check valve on the middle- inlet.  Is there some standard for this?

Per the diagram in the maintenance manual - as I interpret it :
Top inlet : Exhaust
Middle Inelet : to bellows / air bag
Bottom inlet: Air from Tank > through Check valve

I can attach a copy of the page, though it is a bit blurry if that would help.

Thank you!, Phil

Title: Re: MCI-DL345 rear height control valves. Air flow.
Post by: thomasinnv on May 19, 2021, 09:36:45 AM

Check valve needs to be installed on the inlet line to the height valve, flow coming from air tank. If you put it on the airbag line the system will not operate properly.

Title: Re: MCI-DL345 rear height control valves. Air flow.
Post by: plyonsMC9 on May 19, 2021, 11:47:05 AM

Grreeeatt.  Huge help.  Thank you.   ;D
> Phil

Title: Re: MCI-DL345 rear height control valves. Air flow.
Post by: plyonsMC9 on May 19, 2021, 08:27:13 PM

Good evening bus folks!

Could I please get a confirmation on the Air Height Valve air flow?

Based on my MCI DL3-45 manual (attached) it looks like:

Top outlet is the exhaust
Middle outlet is to the bellows / air bag
Bottom inlet is to the air source

Also attached is a picture of my height valve - purchased from MCI but it appears to be generic. 

I've since re-plumbed the valve, putting the check valve and air feed on the bottom inlet. 

Thank you!,

Title: Re: MCI-DL345 rear height control valves. Air flow.
Post by: plyonsMC9 on May 20, 2021, 12:52:01 PM

Worked w/ MCI Tech this morning - word back so far,  is that the body of the height/leveling valves are the same, brackets are different between left & right.  And - that the longer inlet in the body of the valve is always for the air <IN> flow.

I'm waiting for MCI to confirm.

Thanks!, Phil

>> Update:  Talked w/ a second tech @ MCI later this afternoon.  This time, the bottom inlet is for the air <IN> flow.   :o

Title: Re: MCI-DL345 rear height control valves. Air flow.
Post by: RichardEntrekin on May 22, 2021, 10:56:13 AM

Not meaning to be a knuckle head, but this isn’t hard to simulate. Use an airline off any compressor, and play with hooking it up and actuating the HCV until you figure it out.

Title: Re: MCI-DL345 rear height control valves. Air flow.
Post by: plyonsMC9 on May 24, 2021, 07:11:31 AM

I like your thinking Richard!  Will give that a shot, Thank you, I’ll continue to post results here.

Kind regards, Phil