AC rebuild success (almost) - Page 2 - PeachParts Mercedes-Benz Forum

kmaysob · #16 08-26-2009, 11:30 PM

Quote:

Originally Posted by leathermang

Autozone carried R22 in four oz or smaller cans ?

no it was 16 oz i think. but if you use a can tap with a schrader and store it in the freezer you should have it a while.

Cr from Texas · #17 08-27-2009, 01:49 AM

Quote:

Originally Posted by pselaphid

Note the followup comment by Brian Carlton regarding vacuum routing. I have mine routed according to that, confirmed first by blowing through it, applying 12v, then blowing again to figure out the always open and switched orifices. I suppose both options work fine, but his observation makes it a bit simpler. I also removed my aux. pump, which is totally unnecessary in Louisiana.

So what is the default mode (no voltage) valve open or closed? On the original it is open but that thread would suggest it is now closed. Wouldn't that make the CCU work backwards?

Any downside to removing the aux pump?

pselaphid · #18 08-27-2009, 08:33 AM

Default for the valve is no vacuum, valve open=heat. The vacuum solenoid just vents to atmosphere. Applying voltage to the switch routes vacuum to valve, causing it to close=no heat. Thus, it works just like a monovalve, only better.

The aux. pump sucks heated coolant from the head through the heater on cold startups for faster/better heat to the cabin. If you can live without that, you can take out the pump. Its actually a handy little 12v pump for other purposes. WVOers are using them for faster switchover times.

Cr from Texas · #19 08-28-2009, 01:47 AM

Quote:

Originally Posted by pselaphid

Default for the valve is no vacuum, valve open=heat. The vacuum solenoid just vents to atmosphere. Applying voltage to the switch routes vacuum to valve, causing it to close=no heat. Thus, it works just like a monovalve, only better.

OK, that makes sense. I was reading the earlier post as no vacuum = valve closed = no heat. Makes sense now.
Thanks

The aux. pump sucks heated coolant from the head through the heater on cold startups for faster/better heat to the cabin. If you can live without that, you can take out the pump. Its actually a handy little 12v pump for other purposes. WVOers are using them for faster switchover times.[/QUOTE]

I don't remember seeing this on my 123. Can you give me a general idea where to look. I'm convinced I need to install the 1 amp fuse. If I leave the fuse out in summer will the pump being in place but not powered impede the coolant flow?

pselaphid · #20 08-28-2009, 09:09 AM

Look down and to your left (facing the engine) under the air box intake. Should be a mounted above the passenger tire. Attached by a couple small bolts (8 or 10mm) accessed from underneath. Might have to dig the heads out of the rustproofing layer.

Edit: And, no, you can just unplug it and coolant will still circulate. Just be sure the plug contacts can't contact anything and short.

Cr from Texas · #21 08-28-2009, 02:46 PM

Quote:

Originally Posted by pselaphid

Look down and to your left (facing the engine) under the air box intake. Should be a mounted above the passenger tire. Attached by a couple small bolts (8 or 10mm) accessed from underneath. Might have to dig the heads out of the rustproofing layer.

Edit: And, no, you can just unplug it and coolant will still circulate. Just be sure the plug contacts can't contact anything and short.

Thanks, I'll look this evening when the day cools off some and begin by just unplugging the unit.

pselaphid · #22 08-28-2009, 07:21 PM

Now I'm sort of confused about the default position of those Napa valves. See comment on the Monovalve thread, and the speculation about how this might cause engine damage.