The 20 millionth guy with MCI bus A/C issues...

[RickB]

Here is what I know so far. My MCI 9 bus air has been slowly going south over the last year.  I pulled the big filter and cleaned it at the beginning of summer and it had been working (not as cold as when I bought it) okay for the last couple months. Well, before our Black hills trip I took it to a friends shop and we tried to add some freon in the hopes that would fix the problem. He said that both access ports (upper and lower?) were way overtightened. He finally got them loose and hooked up his gauges and we got a zero reading on the upper or top access port and an abnormally high reading on the other one (80 lbs.) at idle. He tried adding freon but the system wouldn't take any. He seems to be convinced that although the compressor clutch is engaging maybe the keyway is sheared (that seems like a long shot to me) I noticed on another post last week that Nick mentioned the possibility of a "blockage" to the flow of freon. Could that be the issue with mine or could it be that the seals on the access ports are ruined because of overtightening or that they stripped and are not really turning at all??. He wants to pull my compressor and rebuilt it with me but I don't want to tear that whole unit out to find out it is something fixable that more experienced folks can help me troubleshoot. After all I do have two 3 ton AC's in the middle bay.

Anyway, it stopped working completely right before we left. Thank God it was cool on the way out and back.

Nick, I fully expect to click my heels together and you will come up with a simple cheap solution... There's no place like home... there's no place like home Toto. Then you can move onto more trying problems like world peace, a cure foir cancer. etc...

Thanks for the help in advance

[John316]

I won't harp (meaning post on every MCI AC thread) on it, but I liked you Subject. We were the 19th million to have problems with ours, and then we took it out and sold it. I hope you get an easy fix for yours (we tried to keep ours, we really did , we just got tired of it after spending $$$$$ on it ).

Good luck.

God bless,

John

[MacGyver]

It seems that the bus A/C systems just require too much time and money and are just a hassle to maintain and keep operational....

I've read a number of posts where the bus system was gutted/ripped out and roof-airs installed for those reasons...

My 4905 still has most of the components, including the dual compressors in the back next to the tranny, but the drive gear is gone and doesn't seem to have any pressure in the system, though...  The compressors don't seem to be locked up.

For all the condensation and rust that they seem to cause...  Roof or basement air seems to be the way to go for longevity...  After all, if you have multiple units and one fails... at least you still have A/C *somewhere* in the coach! 

Hopefully I'll only be replacing the one in mine that completely toasted...  I hope the other two can be salvaged with new control panels and a little TLC...  Not counting on it though...  Good luck!

-Mac

[bevans6]

I too have a probably non-operational MCI ac system.  What do you do with them  when you take them out?  are the parts worth anything?  can you use them for anything?  I'll play with mine for a while yet, but i won't spend any money on it.

Brian

[christopher]

my ac has been wrking since 1978, no issues.
i will have to replace some lines.
i really like the system
chris
mci5c

[John316]

Brian,

I am not sure how much the AC from yours would be worth. We got fortunate, and a guy bought our system from us for $1,200. But remember, he worked on DL3's all day long, since the coach lines still use the DL3's. I am not sure how much yours would be worth. I would try calling some local bus lines, and tell them what you are doing. They might have some ideas (talk to the shop foreman).

FWIW.

God bless,

John

PS Chris, that is great that your system is still working. We weren't that lucky. 

[gumpy]

Rick,

Are you sure the valves on the compressor are in the proper position?  It's possible one of the valves is closed, which would not allow the freon to circulate properly.

craig

[Nick Badame Refrig/ACC]

Hi Rick,

The answer is simple.... Bring it to me! 

Craig stated that the valve ports may not be in the proper position. He very well may be right.

In order to know how to properly position the valves for gauge readings/charging, you really have to have refrigeration experience.

An A/C guy usually never comes accross these type valves and most have no clue how to open them. "sorry"

Give me more info, like is the system still getting cool or a little bit? Or, has it quit suddenly?  Intermittently?

Nick-

[bevans6]

Nick. could you write a bus converters guide to AC systems that would let us understand a bit of how they work and how to do simple diagnostics before going to an expert?  And how to find an expert, aside from your good self?

Things like pulley clutch - how to tell if it is working and what it's supposed  to do when?  What do the sight glasses tell you about fluid levels, and do you read them operating or static?

You can see I know nothing about AC or refrigeration systems.  Maybe even some links to tutorials so that I could try to learn a few things?

thanks, Brian

[oldmansax]

Brian,

I don't want to answer for Nick but, as an A/C - Refrigeration contractor myself, I would be very hesitant to write any self-help guide for the in-experienced. Standard residential HVAC is dangerous enough but commercial transport A/C (like what is on our buses) and refrigeration can KILL you if you don't know what you are doing..... or even if you DO know what you are doing. They can also hurt you bad enough that wish you were dead.

Find somebody who knows what they are doing! I know that is sometimes a problem but look at it as just another problem to be solved .... just like converting a bus. 

Any tech worth his salt should be able to look your system over any give you a GENERAL idea of what is wrong and BALLPARK costs for repairs for a couple o' hundred bucks...... along with OPINIONS on what else might be wrong.

FWIW,

TOM

[SmoothJazz]

Here is a link to Carrier Transicold online Bus A/C manuals. They have some that are specific to MCI E coaches and MCI G coaches. I believe the systems were set up pretty much the same as the MCI 9 coaches. They used the same 05G compressors in all of these models. They are all printable at no charge.

http://findstuff.biz/search.cgi?q=carrier+transicold

[RickB]

Nick and crew,

First of all I admit openly that I don't have a clue how AC works and about mt only redeeming quality when it come to electricity in general is a profound ability to shock the living daylights out of myself. That said, the system was sort of intermittent until we worked on it (thats a bad sign I'm sure) it was cooling the bus it just wasn't icy like when we first bought the bus. As I said I have two bay mounted AC units but I don't like running my generator all the time.
The return was kinda cold the last few times it worked. I am not sure if I know any reasonable Bus AC folks here in Minneapolis and I can't stick a bunch of money into this as summer winds down up here.
Nick, can you be more specific as to the correct way too close and open the access ports?

Thanks,
Rick

[Nick Badame Refrig/ACC]

Hi Rick,

As Tom stated, it's not a good idea for you to be playing with the valves yourself.

If you pass this info onto your servive guy, I will relay what you should tell him.

Both Rotolocks [valves] should be fully backed out counterclockwise for normal running operation.

To access ports for your guages, first connect both hi and low side lines. [red to the smaller or high side and blue to the larger or low side.

Next, each rotolock valve should then be opened one full turn clockwise to access pressure to your hoses. Do not seat the velve fully closed...

This should be the fix your looking for.

Nick-

[RickB]

Nick,

I think I speak for the entire board (because bus A/C is an almost universal trouble spot) when I say:

You Rock!!

Thanks,

Rick

FWIW to address your concern about me messing with this issue, you wouldn't catch me putting a wrench anywhere near that compressor with the motor running.