ENGINE A/C PROBLEM, NOT ALWAYS COOLING
We have a 2006 Coachmen Aurora Class A motor home with a Ford F53 chassis and a 6.8L V10 engine. We are having intermittent problems with the engine A/C system. We've evacuated the system (3 times),...
Forum Discussion
1. I seriously doubt the output air was below 40 degrees. That mechanic either has a seriously un calibrated thermometer or he lied to you. You will NOT get below 40 degree air output on a class A motorhome unless the ambient temp was below 60 degrees.
2. Yes, you jump the 2 wires together on the 12 volt tstat freeze control to bypass.
3. The difference between MAX air and just AC on a motorhome is on MAX air the lower outside fresh air intake door is closed to allow recirculation of interior air which will result in colder output air. On just AC that lower door is opened and that allows hot ambient air to flow thru the Evaporator and will make getting colder temps harder.
4. The SPEC for Class A Dash AC systems is 60 degrees or below. But, almost all systems will get 55 or approach 50 degrees. When properly charged.
5. PROPER Charge is critical for a Dash AC system. TOO MUCH 134a and it will not cool correctly and will kick out the hi pressure switch. TOO LITTLE 134a, and it will not cool properly. Do you know how many OZ'S of 134a they installed? Your Ford requires either 2.25 lbs or no more than 2.75 lbs.
6. 134a systems, you CANNOT charge by the sight glass like Freon 12 systems. A fully charged 134a system will still show bubbles in the sight glass. You MUST install the exact charge to get optimum performance. The Evans/Tempcon Website will show the actual charge for your particular Ford chassis. Doug
2. Yes, you jump the 2 wires together on the 12 volt tstat freeze control to bypass.
3. The difference between MAX air and just AC on a motorhome is on MAX air the lower outside fresh air intake door is closed to allow recirculation of interior air which will result in colder output air. On just AC that lower door is opened and that allows hot ambient air to flow thru the Evaporator and will make getting colder temps harder.
4. The SPEC for Class A Dash AC systems is 60 degrees or below. But, almost all systems will get 55 or approach 50 degrees. When properly charged.
5. PROPER Charge is critical for a Dash AC system. TOO MUCH 134a and it will not cool correctly and will kick out the hi pressure switch. TOO LITTLE 134a, and it will not cool properly. Do you know how many OZ'S of 134a they installed? Your Ford requires either 2.25 lbs or no more than 2.75 lbs.
6. 134a systems, you CANNOT charge by the sight glass like Freon 12 systems. A fully charged 134a system will still show bubbles in the sight glass. You MUST install the exact charge to get optimum performance. The Evans/Tempcon Website will show the actual charge for your particular Ford chassis. Doug
