Hot air coming in while moving and keeping cool

luvrbus · June 19, 2018, 08:53:11 AM

The original coach air is about the only thing that will over come the leaks and air loss on a bus ,I have 5 roof airs Penguins with a 20kw generator and wish I had the OEM air conditioning because of the generator time

neoneddy · June 19, 2018, 09:02:57 AM

I'm not giving up with out a fight :-) If there is one thing I'm good at, it's being stubborn.

buswarrior · June 19, 2018, 09:05:15 AM

OEM, there is fresh air into the dash, silver handle down at left knee (not ankle) controls a damper door inside dash. If it doesn't seal closed, nothing you do will cool underway. The intake is on the front above the bumper. Tape 'em shut for now.

It is nice for this to work, as you get nice, fresh warm ram air in the heating season, like your car.

The stock HVAC gets the fresh air via the two small grills face height, back of the front wheels. You may simply tape them over on the outside for a simple fix for now.

Fibreglass insulation is useless against air intrusion. You need to seal the air gaps, not filter them!

Happy coaching!
Buswarrior

luvrbus · June 19, 2018, 09:21:45 AM

Quote from: neoneddy on June 19, 2018, 09:02:57 AM
I'm not giving up with out a fight :-) If there is one thing I'm good at, it's being stubborn.

Good luck but it is a up hill battle trying to cool a 40ft bus with 26 or 30,000 btu of AC when driving,the AC in your automobile or pickup are 28 to 45,000 btu.Living in AZ 2 roof tops would get you nowhere on a spring day

lostagain · June 19, 2018, 11:47:57 AM

OP? b/c? means?

Those abbreviations are annoying for sure. Sometimes I don't know what they mean and have to look them up. The posters using them are just lazy and wrongly assume that everybody knows what they mean. How long does it take to type a word full length ?

JC

richard5933 · June 19, 2018, 12:23:34 PM

Quote from: luvrbus on June 19, 2018, 08:53:11 AM
The original coach air is about the only thing that will over come the leaks and air loss on a bus ,I have 5 roof airs Penguins with a 20kw generator and wish I had the OEM air conditioning because of the generator time

This post makes me feel at least a little bit better about the last three weeks of struggles getting out OTR a/c working again. A series of small obstacles that have added up to cause big delays.

Back to the original topic... Isn't it odd that however much fresh air seems to rush in to heat the bus when the a/c is running, it never seems to be enough to keep it comfortable enough to shut the a/c off.

I agree about the side and front vents. Now that you know where they are I'd suggest sealing them best you can so that the fiberglass can go back to insulating, since it's not terribly good at sealing anything. Whatever you can do to stop the flow through these vents is going to go a long way to keeping you comfortable inside the bus. However, come fall when the weather turns colder and you want to remove condensation inside the windshield, you might find the need to let in some fresh air. I'm assuming that you've got a window that can be opened, but if not then you might want to find a way to get the damper working.

When I found the damper for our nose vent it was not working to block incoming air, but a 1" thick layer of foam and some weatherstripping on the sheet metal damper made it so that now it works pretty good.

Jim Blackwood · June 25, 2018, 08:48:02 AM

About that pressure differential.... What causes it, is there a reason for it, and is there anything that can be done about it?

I've heard over and over again how it causes toilet odor to enter the living space. Surely we have the technology...

Jim

neoneddy · June 25, 2018, 10:49:12 AM

Good news, took the ol hound out for a quick spin up to Cambridge (30 miles) plenty of time to get everything hot that was going to. It got well into the 80s this afternoon and with the only real change being the insulation in the tunnel we held a nice 74 all the way there and back.

The wife said she felt some warmth from the door area still, I checked the driver's heat radiator, it was cold / not warm. Only thing we can figure is the door iself specifically the bottom area where the manual says it let's in some air in. I've got some rubber door seal stuff I'm going to try.

I know we haven't hit the west 90+ degree heat yet, but I'm hopeful with my cellular blinds and shades we can keep the sun at Bay and comfortable with 2 ACs.

@jim... now that is something I'll need to watch for. Don't want that stanky smell coming inside. Would PVC check valves on the vents help? Lets gasses out, but stop a vacuum condition sucking air in?

luvrbus · June 25, 2018, 11:07:12 AM

LOL a 90 degree day out here is spring or winter time temps people don't even turn a AC on for that temperature,get you taste of the 117 we had last week

solardude · June 25, 2018, 08:59:34 PM

Quote from: Jim Blackwood on June 25, 2018, 08:48:02 AM
About that pressure differential.... What causes it,

Fluid Dynamics is the cause. I don't think it is a simple enough subject to explain here, but I bet if you google it, you will find more than you would ever want to know about a bus moving through fluid.

As for the toilet smell, there is a gadget you can buy to attach to the vent pipe on the roof to pull a low vacuum on the tank as you drive down the road.... it too uses fluid dynamics.

SD

Branderson · June 26, 2018, 06:24:37 AM

Quote from: lostagain on June 19, 2018, 11:47:57 AM
OP? b/c? means?

Those abbreviations are annoying for sure. Sometimes I don't know what they mean and have to look them up. The posters using them are just lazy and wrongly assume that everybody knows what they mean. How long does it take to type a word full length ?

JC

Original Poster and Because

luvrbus · June 26, 2018, 06:33:58 AM

LOL I don't have a problem with AC I know what it means,this why I don't do texting I never understand the abbreviations people use

buswarrior · June 26, 2018, 06:37:31 AM

The bus door lets air OUT.

The same as the toll window, air is sucked out, as there is a lower air pressure region just aft of the bus front, when it hurtles thru the air.

Bothj moving and sitting still... the coach door can ruin your hVAC efforts.

Happy coaching!
Buswarrior

buswarrior · June 26, 2018, 06:38:12 AM

The bus door lets air OUT.

The same as the toll window, air is sucked out, as there is a lower air pressure region just aft of the bus front, when it hurtles thru the air.

Bothj moving and sitting still... the coach door can ruin your hVAC efforts.

Happy coaching!
Buswarrior

luvrbus · June 26, 2018, 06:47:02 AM

Glass and the metal heat soaking kills the AC unless you have enough BTU to over come it or use plenty of closed cell spray foam on the top,floor and sides