Original in bus heater/AC questions

[Roci]

Good morning all,
Our bus is a 2006 Thomas Saf T Liner with a CAT C7 diesel and Allison 5 speed automatic 24 seater with mid bus lift, that we’re leaving in for Our daughter and her wheelchair.
We’re just starting and just removed the bus seats.
Im a little confused about removing the heater and AC. Does everyone do it? Is there someone out there who hasn’t? It seems important, and ours is in great working condition. If we removed it for conversion purposes wouldn’t we then be without climate control while traveling even in the front of the bus? How would we defrost the windscreen?
Is there a way to keep lines but have them there to supply the drivers area and not the whole bus? And same question for the AC?
Thank you!

[Biscuitsjam]

No. Yes. Yes. You wouldn't without replacing the lines. Yes. Yes.

[Roci]

Thanks biscuitsjam
Do you know of anyone who’s done this? With links and advice? It’s good to know it’s been done, I’d love to see an example.

[Biscuitsjam]

The coolant lines Tee off from the engine and run through the defroster and all the heaters and then back on a return line. On my bus, it was a 1" diameter hose. Each heater has the line go back and forth inside it as a sort of heat sink, and will generate heat whenever coolant is running through the lines. Additionally, the defroster and each heater has a 2 or 3-speed fan that will greatly increase the heat output of the heaters.

There is typically a lever-operated heater valve near the driver to shut off the heater lines. Additionally, most buses have manual shut-off valves located near the engine for maintenance purposes. As the lever-operated valves are unreliable, often the manual valves are closed during summer months.

Additionally, full length buses will have a "heater booster" switch. This turns on a 12 volt water pump to increase coolant flow to the heaters. Without it turned on, coolant flow will be very low and very little heat will be generated.

Some diesel engines also have a thermostat that will prevent heat from going to the heaters until the engine is fully warm, but I don't know how many buses have those installed.

Often, there will also be a lever-operated vent to let outside air in through the defroster. If it's open, you'll have a hard time keeping your bus a comfortable temperature in hot or cold weather.

[Biscuitsjam]

If you want to remove the rear heaters but keep the defroster, you'll need to disconnect all the heater lines and run new lines direct from the engine to the defroster and back. It's not especially hard.

However, you may want to consider repositioning or replacing your existing heater cores to continue to be able to use engine heat.