AC heat pump failures

[masoncr@aol.com]

I have a 2006 Tiffin Phaeton 35DH. It has two RVP 15,000-btu heat pump/air conditioners. The rear unit is working on both heat and air as expected. The front unit will fail sometimes in the AC mode. This generally happens when the outside temperature is over 100 degrees, only one occasion less than 100 degrees .... This is not a repeatable failure. It may work for days at a time with no problem in as much as 106 degree heat. It appears that the compressor is turning off, the fan continues to run and warm air is being sent through the system. I then turn the system off. After about 30-plus/minus minutes I can turn the unit back on and cold air will generally be produced. It may continue to work properly or fail once again.

I have had an A/C technician attempt to diagnosis the problem. There was never a failure in his presence. He checked all measurable components and all were within specs. He even double checked with factory reps. Coils were not dirty and there was no icing. Return air and output air differential was 18 degrees.

This fall I had a need to use the Heat Pump. Again rear unit worked as expected. The front unit did not. On one occasion, with the set point at 72 degrees and outside temperature in the 50s the unit quit producing warm air. I assume that the compressor had turned off. This again does not happen all the time. Unit would often work well with outside temperatures in the mid 40's. During this trip, this failure repeated itself four or five times. After turning the unit off for 30 plus or minus minute's warm air would normally be produced.

[tbutler]

Have you been able to monitor the quality of the electric supplied to the coach? I have seen the voltage drop into the high 90's at some RV parks, especially when the area is experiencing extreme temperatures. There are even parks where the voltage isn't up to par on good weather days. It could be that one unit is more sensitive to voltage fluctuations than the other and so it drops out first, allowing the other unit to get adequate voltage to keep going. I always monitor the voltage when we get to a new park to assess how adequate it will be. At good parks it stays near 120 V AC no matter what the load is. At some parks it starts at 115 or 120 V but the first time you make coffee or turn on the electric water heater it drops quickly. Then you know you are in trouble. Since a tech can't find a problem, I would suspect the electrical supply as a possible culprit. When the tech was testing the unit it likely had an excellent current supply. Then you take to the field and you find problems, sometimes. Sounds like a good park with excellent electrical supply and then occasionally a park with a poor electrical system.

[jbell]

Next time this happens disconnect your shore power (safety precaution) and start you generator. If the AC works properly you most likely have low voltage input from the shore power. You should always monitor your voltage in any case. Good luck!

[masoncr@aol.com]

Next time this happens disconnect your shore power (safety precaution) and start you generator. If the AC works properly you most likely have low voltage input from the shore power. You should always monitor your voltage in any case. Good luck!

Jimmy Bell and TBUTLER Thanks for your reply. This problem has happened at numerous different parks. I have a surge protector installed that will disconnect my power source at any time voltage falls below 102 volts. However voltage for the front unit may be more sensitive. I will try using generator, when this will not be inconsiderate to fellow campers. I will also check incoming voltage from shore power source.