1988 Model 15 Heat/Air Return

[Stephenat]

Hello all,

This is my first post, but our gospel group has had our Eagle since 2003. We bought it from Easter's Bus sales and have enjoyed it. It was a Greyhound out of Houston that we have converted ourselves.

On to my question....recently while we are traveling down the road, very hot air has been coming out of the bus air returns. We don't use the bus air much, as it has two 1.5 ton heat pumps on the bus. Any ideas on what would cause hot air to radiate out of the air returns?

Thanks!

-Stephen

[beltguy]

Hi Stephen. Welcome to to our forum

It sounds like you retained both the original bus heat and AC. Assuming that is the case, it sounds like the heat control valve has gone bad or the adjustment has changed.

I am not familiar with the heat control system on your bus, but an easy temporary fix is to shut off the flow of engine coolant to the coils. There should be a ball valve on the engine that will shut off the flow. It is usually down low, towards the back of the engine (towards the front of the bus). I have changed engines, but I think mine was on the driver's side.

Jim

[Stephenat]

Thank Jim! I will have that checked out. I sure appreciate you taking the time to reply.

[beltguy]

I looked in my maintenance manual and there is not a lot of detail about the heating system. The attached photo shows a control system using a "Gradustat". I am not familiar with that system, but it is an air control system. If the air supply is lost, I am not sure if the system will default to hot or cold. If it defaults to hot, then the first place I would check would be the air supply/control lines.

Jim

[Stephenat]

Wow! Thanks for that info. I think we have a maintenance we paid $400 or so for. We have looked in it, but nothing stuck out as to be something that we should check. I will compare ours to yours and see. Thanks again my friend.

[beltguy]

I did a bit more research and found this thread: http://eagles-international.net/forums/ ... 98&p=16583

If I read the data correctly, a loss of air would send the system into heat mode.

Jim

[Stephenat]

Thanks again, Jim! We may have to pull the carpet up in the back lounge to get to that access panel. It would be great if there was just a valve on the engine that would cut it off...at least during the summer.

[beltguy]

To shut the ball valve off, you should be able to get to it easily by crawling under the bus.

If it has not been opened/closed in a while, it could be a challenge.

Jim