Cooling

Roof Vent Fan, Air-conditioner

Before going on to describe the fan and air conditioners, we should let you know sprinter vans are very difficult to cool off in summer. There are several things you can do to help if you have the 12-volt DC air conditioner.

• Run the roof AC while driving – If you have the Li3 battery, about 1/2 to 1 hour before you arrive at your camp site, turn on the roof AC while driving. This will cold-sink the interior and give the roof AC a head start cooling the van instead of trying to cool a warm van.
• Idle the Engine – After arriving at the campground, leave the engine idling for a few minutes to run the dash AC while you are hooking up the utilities. This will also give the turbo charger a few minutes to cool down.
• Open the hood – Once you’ve shut off the engine, open the hood to let the engine cool down quicker instead of holding all that heat next to the firewall.
• Install an external windshield cover. Blocking the heat before it can enter the windshield is better than trapping it inside like a greenhouse.
• Install a curtain behind the front seats to reduce the size of the air volume the roof air conditioner has to cool.
• If possible, park with the front of the van facing the sun, rather than heating a side of the van.
• If the sun is on the passenger side, extend the awning to shade the side. (Unfortunately, the newer awnings can’t be angled down to provide more shade.)
• Use a sun screen mesh that attaches to the extended awning to shade the side of the van.
• Lower the window shades and Install interior window covers to block heat coming through the glass.
• Apply heat blocking film on the exterior of the windows. We installed VViViD perforated window vinyl and it lowered the glass temperature 20 degrees.
• Most 12 volt DC air conditioners lack enough blower pressure to push cool air to the front of the van. Small fans inside will help circulate the cool air a little better. Some roof fans can run with the dome closed to operate like a ceiling fan.
• A dehumidifier can reduce the humidity and lower the “feels like” temperature.

Roof Vent Fan

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12 volt ACs

Many Class-B manufacturers have switched to installing 12-volt air conditioning units on their Class B motorhomes. When boondocking, a large lithium battery is recommended along with a second engine alternator to power the AC without the need for an onboard generator. These air-conditioners can also be operated while driving to add additional cooling to the van.

Testing – If you are questioning if an AC is working properly, run the AC for 15 minutes and measure the temperature of the air entering at the filter and the temperature of the cold air exiting the vents. If you see a 20+ temperature difference then it is operating within specifications.

Humidity levels, sun load on the outside unit, and several other factors can affect this temperature difference. With increasing temperatures outside, the compressor must work even harder to compress the gas back to a liquid state, drawing more current. Higher ambient external temperatures also decrease the heat transfer capacity of the condenser coil.

Vans are a large metal box and difficult to cool, especially with the miniscule amount of insulation used in the Galleria build. See our tips on cooling.

UPDATE: There have been so many issues with the 12 volt ACs it appears Coachmen is now offering the Truma 120 volt units on new vans.
UPDATE: Sounds like there are problems with Truma AC also. It can’t run on the generator since it draws more power than the generator can output. There isn’t a “soft-start” module available at the moment but Truma is testing one.

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Air-conditioner – ProAir 12 volts

Maintenance:

Clean – the reusable interior filter with plain water. Loosen the 4 screws and remove the cover to access the filter.
Wash – the exterior coils once per year to remove grease and road grime from the fins. Pressure washer is not recommended and could damage the fins.
Fuses – There are several fuses located inside the unit, under the filter. You may want to have some spares just in case.

Problems:

The power cable size is 2 gauge. There were recalls of early installs because coachmen miscalculated the gauge cable required and had to replace with heavier cables.  There have also been numerous issues with bad installations that resulted in water pouring out the filter onto the bed. Some owners are on their third ProAir.
Other issues were bad crimps in cable resulting in a low voltage shutdown when the compressor starts. After numerous problems, coachmen now installs the Turbo Air II.

Modifications:

One of the projects after the purchase of Gal_1.0 was to test other fans to find one that would be quieter with similar air flow specifications. Contact us for more information.

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Air-conditioner – Premier Products Turbo Air II

The Turbo Air II is a 22,000 BTU with a 285 Cu Ft/Min air flow.
NOTE: Some people have questioned the BTU claims of RV air-conditioners based on the formula:
BTU = CFM x ΔT x 1.08
BTU=285x25x1.08
BTU = 7,695 not 22,000 BTU ???

Maintenance:

Clean – the reusable interior filter with plain water. Loosen the 4 screws and remove the cover to access the filter.
Wash – the exterior coils once per year to remove grease and road grime from the fins. With the fins located to the front of the unit, you can expect more bugs will meet their maker with this design. (Designers obviously have never been to Florida during Love Bug season!) Pressure washer is not recommended and could damage the fins.
Fuses – There are several fuses located inside the unit, under the filter. You may want to have some spares just in case.

TIP#238: Remove one Vent – to get better cooling to reach the front of the van. Removing two reduces pressure and is less effective on our Turbo-II.

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Truma Aventa

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13 – Heating
14 – Cooling
15 – Electrical System

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