AC question

[vontrial]

I have a 2000 frtliner fld120 the ac does not work in the back bunk,it will blow air but its hot will not cool. Work fine in the cab of truck. Any suggestion . Thanks in advance.

[jiptwoo]

It could be a number of things, ie. under the bunk there should be a seperate evap coil. It could have a dirty filter or coil needing to be blown or vacuumed out. There may be a solenoid valve which allows refrigerant to flow to the coil that is not working, or maybe a closed damper which is not allowing the air to flow thru the coil, there by no cooling, hope this helps.

[boneebone]

There is also a bunk air filter underneath there. If it is dirty and clogged the A/C will not be as efficient.

Could be as simple as closing the hot water valve in the engine compartment. Keep in mind there are 2. One for the cab and one for the bunk. Both should be closed for the summer.

[vontrial]

Thanks for the reply will start checking today.

[Blind Driver]

Got the bunk a/c button in the on position?

Ummm...I've never made that mistake

[roadranger]

My 1995 FLD120 doesn't have shutoff valves! The cab heater has a valve that is controlled by the "temp" lever and seems to shut off completely when in the "cold" position. The bunk heater has an electric solenoid valve that controls the air to an air operated shutoff valve. My valve was leaking air when "on" so I disconnected the wire to the solenoid valve yesterday. Unfortunately the unpowered state of the valve is "on" so I had to get a manual shutoff valve - coulda baked cookies in there :shock: ! I bought a 1/2" ball valve from Home Depot with 1/2 female pipe thread inlet and outlet. They didn't have 3/4" hose barbs with 1/2" male pipe threads so I had to pick them up at a truck parts store. I tried to clamp one of the hoses off near where they enter the bunk through the floor but didn't get it clamped well enough to prevent loosing a half gallon of coolant :sad: . I clamped it in two places so that I could cut out a piece of the 3/4" hose to insert this and stuck it in and clamped it. Oh - make sure you remove the pressure cap before doing this! I would like to install valves right on the water pump someday - that is where the two hoses are connected for the two heaters. I'd use the same ball valve with a pipe nipple to convert the inlet to male and it appears that the hoses are attached to a 3/4" to 1/2" reducer with a 1/2" pipe to 3/4" hose barb I could re-use. Or - I might replace the heater hoses as they look a bit ratty and go down to 5/8" size? Real P.I.T.A. to drain and capture the coolant for re-use though. About 16 gallons I think? Did it once already to remove a real ratty fuel heater that worked off the coolant.

[roadranger]

Oh, and I usually have the heat on part way with the A/C unless it is over 85 as otherwise I freeze even on fan speed one :shock: ! I superglued all my vent controls open as otherwise the flaps fell shut as they are quite worn after 12 years. That made the system work much better. Oh, and on the bunk system - the heater valve would only shut off if you turned on the blower so when you first turn on the bunk A/C blower after the engine is hot it blows very hot air until the heater core cools down - what idiot designed that :shock: ? I suspect the bunk thermostat will no longer function with the manual shutoff as it seems to just kick on the heat when it gets too cold and it can't do that with no hot coolant flowing.