35000 BTU A/C freezing up
Our 2002 Keystone Sprinter 28'fifth wheel with a single AC has been freezing up. It has happened before when we were in high humidity areas but we are in UT where the humidity rarely gets to 20%. Even...
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My mistake; it is a 13500 BTU AC, not 35000!
Here's what I've found that remedied the situation:
1. The insulation between the return air and cold air behind the filter in the ceiling had several voids in it. I repaired/recaulked/retaped these. This was probably causing most of my freeze up problem due to cold air returning to hit the evaporator.
The switch that is attached to the evaporator coil that shuts off the compressor when the coils start to freeze up WAS securely attached to the coil.
2. In 12 years, sorry to say, I'd never cleaned the coils up on the roof. I removed the evaporator protector cover and used a hose (carefully, so water didn't go down into the RV) and used somewhat low pressure to clean the evaporator fins which were dusty, but not caked with lint, etc.
3. I also used higher pressure (hose pressure @ 50psi) to squirt out the condensor coils, radiator fins(both sides), and water drain to the roof.
4. I carefully unbent several areas of condensor(radiator?) fins using a plastic spoon.
5. After this, I ran just the fan, on high, for about 30 minutes to dry everything out.
6. Before putting on the roof cover, I ran the AC for 15 minutes so I could determine if the suction line was cold (frosting), which it was. According to what I've read (including the manual someone posted a link to; thank you!) this indicates that you are probably NOT low on coolant. The manual says it is RARE for an RV AC to be low on coolant, unless it's been physically damaged It is a closed system from the factory, with no place to recharge it. If the AC has worked properly for quite a while, then the chances there's a leak or that it was a defective unit from the factory are slim. Look elsewhere.
Most research I've done says to keep your filter clean and NEVER run the unit without it. Set your thermostat
It is cool here today, so I can't really check everything out for cooling ability, but there is considerably more air moving through the vents now and I'm confident that the problem has been solved. If not, I'll repost. Thanks for the suggestions and help.
Here's what I've found that remedied the situation:
1. The insulation between the return air and cold air behind the filter in the ceiling had several voids in it. I repaired/recaulked/retaped these. This was probably causing most of my freeze up problem due to cold air returning to hit the evaporator.
The switch that is attached to the evaporator coil that shuts off the compressor when the coils start to freeze up WAS securely attached to the coil.
2. In 12 years, sorry to say, I'd never cleaned the coils up on the roof. I removed the evaporator protector cover and used a hose (carefully, so water didn't go down into the RV) and used somewhat low pressure to clean the evaporator fins which were dusty, but not caked with lint, etc.
3. I also used higher pressure (hose pressure @ 50psi) to squirt out the condensor coils, radiator fins(both sides), and water drain to the roof.
4. I carefully unbent several areas of condensor(radiator?) fins using a plastic spoon.
5. After this, I ran just the fan, on high, for about 30 minutes to dry everything out.
6. Before putting on the roof cover, I ran the AC for 15 minutes so I could determine if the suction line was cold (frosting), which it was. According to what I've read (including the manual someone posted a link to; thank you!) this indicates that you are probably NOT low on coolant. The manual says it is RARE for an RV AC to be low on coolant, unless it's been physically damaged It is a closed system from the factory, with no place to recharge it. If the AC has worked properly for quite a while, then the chances there's a leak or that it was a defective unit from the factory are slim. Look elsewhere.
Most research I've done says to keep your filter clean and NEVER run the unit without it. Set your thermostat
It is cool here today, so I can't really check everything out for cooling ability, but there is considerably more air moving through the vents now and I'm confident that the problem has been solved. If not, I'll repost. Thanks for the suggestions and help.
