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Dash Air question
On my Rorayle I have an evaporator in the dash and a second evaporator and fan above the dash. The one in the dash is putting out 60 deg air and the one above the dash is putting out 47 deg air. Ambient air temp is 72 deg. Both evaporators are connected to the same compressor. Any thoughts on why there is such a difference in temp between the two evaporators?
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11 Replies
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Length of ductwork, system hi and low pressures at each evaporator, efficiency of evaporator, type of control of hot liquid (expansion valve, cap tube, etc).
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In a coach intake air can be differant. Spread in air temp at ceiling could be 80 deg with the fact that heat rises and cold falls the intake air could be 10 degree differant. or 70 degree. Mixing air layers top to bottom will give you a more constant intake temp . I have done this with a small ceiling fan(20 inch) mounted above driver. Just a possibility that I take care of when building coach as a home builder. Bob
On the present build I took care of the layering by usind a evaporator that has moving vents both horrizontal and verticle. No ceiling fan needed this time. Bob -
Andre,
Both my evaporators in my Royale blew the same temps, COLD. You may have an expansion valve problem.
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Guys remember the upper one is putting out colder air.
Do you have any electronics in the dash that could be raising the air temp either intake or output?
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No electronics, it is a Royale, as simple as they come. I seem to remember the lower vents blowing a lot colder. At first I thought it was a low freon or compressor problem, but with the top blower putting out very cold air I am starting to think Tom might be right and it is the expansion valve. Just need to consider all the options. I may just have to take it to an shop and have it looked at.
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You have to be sure you are measuring the same way.
Is the bottom evaporator getting recirculated air or air from outside? How far from the evaporator are you measuring temps? Is the upper evaporator getting recirculated air or outside air? Are the fan speeds the same?
How do you know the system is delivering the refrigerant properly? Is the lower evaporator iced up?
I think you can drive yourself nuts trying to fix what isn’t broke.
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On a 1997 Royale, do the heater valves in the engine compartment have to be off for the dash AC to work? The compressor was bad and has been replaced but i still have no dash air. I happen to be one of those buyers of a Prevost that had no help in the workings of the systems and the learning curve is mighty steep. I must say though I’m getting a good handle on it with the knowledge that is present on the PC forums. Notice I said PC and not some other forum 😊
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Andre,
The valves don’t have to be off, with them on, it allows you to adjust your AC temperature just like you would in a car. I always turn them off in the summer to make sure I get maximum cooling from the dash air. I had a blend valve leak through one time (wouldn’t shut off the coolant) and the AC just wouldn’t get cold enough and that was the problem.
I doubt this is your problem since you don’t have any AC.
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Thanks, I’ll look elsewhere maybe the refrigerant solenoid valve or the expansion valve. Life is never dull with a Prevost. .
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Make sure to push the AC button on the dash on it will engage the clutch there is a time out before clutch will engage , but you might have done that all ready . I had a 1997 Royale toooo it was great coach
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Thanks Peter, I really like the simplicity of it. This coach was in my opinion neglected somewhat so I’m trying to get all the small things taken care of before I can go ahead with an updating which will be small but very much needed. It really is a great starter coach.
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