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Topic: Dash a/c blower not blowing very hard for a bus (Read 578 times) previous topic - next topic

Dash a/c blower not blowing very hard for a bus

Hi I would like to know if my 2000 U320 dash blower is normal for a Foretravel?
It blows ice cold and the 3 speed fan works on all 3 modes fine. But it just feels substandard for a big bus. Is this status quo for that year? Or is there a potential issue that I can correct it? Is it possible there is a cabin a/c filter? Doubtful. Also how do I access the blower behind the dash?  Has anyone tried to install a higher cfm blower? Thanks in advance for any advice.
RD

Re: Dash a/c blower not blowing very hard for a bus

Reply #1 –
My Dash air works well but it's not designed to cool off the interior. When it gets hot we run the generator and front AC to keep us and the dogs cool.
1993 U300 40ft GV SE
Build # 4344

Re: Dash a/c blower not blowing very hard for a bus

Reply #2 –
I think a lot of us wish that dash air had a more robust fan. My experience is the same as Jeff's; when it gets really hot the dash air just can't keep up. For example, while driving west yesterday my dash air did great until the ambient temp hit around 90. Then, it was time to supplement it with the roof airs.
jor
93 225
95 300
97 270
99 320

Re: Dash a/c blower not blowing very hard for a bus

Reply #3 –
Some have been known to put up a shower curtain behind front chairs to keep the dash cold air contained.

Our style is to run our Vornado floor fan blowing on driver & co-pilot, no curtain for us.

Most just run gen & roof air to supplement dash air.

No, there is no filter to change. We do have a wired remote thermometer with sensor in the plenum down near the evaporator coil, and if we see a very cold temp, we know the unit is doing the best it can, and we don't have a refrigerant problem.

Re: Dash a/c blower not blowing very hard for a bus

Reply #4 –
It's pretty easy for one of the hoses/ducts to come off under the dash resulting in poor cabin airflow on most vehicles. The fan size most likely cannot be increased as coil face velocity may exceed 525 feet per minute and start blowing the condesate off of the coil fins and past the drain pan making a mess.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Dash a/c blower not blowing very hard for a bus

Reply #5 –
On our 96 coach, the dash air would not keep up in summer months.  Ran generator all the time with both roof airs.  Our 05 coach will stay cool with the dash air running and the rear vent fan sucking out the hot air in all but hottest days.
Steve DeLange
2005 U320T 40'
Pearland, Texas

Re: Dash a/c blower not blowing very hard for a bus

Reply #6 –
I replaced both my Spal blower fans in January...the bushings dried out and they squealed horribly until one of them seized and let the smoke out.  Could not find any replacement fans that would fit without major modification/fabrication, and the Spal replacements are NLA anywhere but the mothership. 

After I replaced them, my A/C was still anemic until I discovered that the hvac vacuum generator (yours is most likely where mine was...in the step well) was toast and the flappers in the dash were therefore inert and misdirecting air, most likely getting little or no air across the evaporator.  Replaced the vacuum generator with a 12v ford diesel vac pump.  Now in Max A/C (recirc) it gets too cold to keep in full cold on the temp dial.  FWIW, completely disassembling the dash to get to the fans was not fun but doable...lots of info on beamalarm on the dash/hvac box and hvac vacuum.  Woody.
2001 4010 U320 build #5865 "Bluto-d-Bus" since 09/18
2006 Honda Element ESP Toad
Full timing since 2016 in Western MT
Copilot: Sitka
1975 GMC 260 Avion: sold
 

Re: Dash a/c blower not blowing very hard for a bus

Reply #7 –
I don't think this is your issue BUT when a fan is operating properly but you loose volume while in operation it will usually be a freeze up. Then either turn unit off or back off heat cold control to heat to let it thaw. I'm having a bit of that in Florida last couple days in heat and humidity. It has froze up a couple times but blows 32 when not. Just for anyone's future notice in case they weren't aware.
Dub McBride 1996 270