B190 Enthusiasts

I finished installation of a replacement main cabin roof vent. Here is a photo of the main cabin roof vent of the B190 that I recently purchased. The sun had pretty much cooked anything plastic mounted on the roof including this vent.

I purchased the Maxxair MaxFan Deluxe. The main reasons for choosing this exhaust fan is (1) since the vent draws from underneath its shroud, the vent can remain open even when it is raining and (2) the vent’s fan can draw air in or exhaust air out and can also operate with built in thermostat for automatic control.

Here is the new vent in closed position.

Here is the vent in open position. Note the the opening on the underside of the vent hood and the side guards to prevent rain from coming in the sides of the vent.

Here is a view of the controls.
- Manual knob to open and close. Push the knob to lock the position.
- + and - buttons for 10 fan speeds.
- Button to reverse fan direction. Direction can be switched even while the fan is running. The fan shuts down, pauses and starts up in the opposite direction.
- Button to activate the thermostatic control and set the target temperature.
- On/off button.

Wow. That is a badass fan system. I am jealous.

Much of our camping will be without 110v. So since we will not be able to run the air conditioner, I decided to "level up" our ventilation fan system. It looks to be a well thought out design.

That's pretty nice. I thought all of the B190s came with the Fantastic Fan, but your original fan definitely wasn't one (the FF has a cover similar to your old one, but the fan blades and interior look like the new one).

okay....so this is what we are going to do (i.e.copy you). My fan leaks like crazy due to everything being so extremely brittle! The cover is cracked, the fan itself looks wretched!

Can you open it while you are driving?

Just out of curosity, why did you pick this one (instead of the Fan Tastic fan)?

Also, did you have to replace the one above the shower?

Y'all ROCK!

ggeorgiagirl,

Q) Can you open it while you are driving?
A) The lift mechanism is well made and appears pretty robust. Slow speeds, no problem. However, I don't drive with it open at fast speeds as I don't want to risk wear and tear with the wind beating on the plastic lid. When rolling, I think opening the B190's side windows is a lower drag ventilation option.

Q) Just out of curosity, why did you pick this one (instead of the Fan Tastic fan)?
A) Because this model vents from the underneath side of the hood. So it can be open even when it is raining. The Fan Tastic Fan models that I have seen have open sides allowing rain to splash or blow in when in the open position. I have seen covered shells that can be mounted over the top of the Fan Tastic Fan. But, that means that the height of your roof line is permenantly taller. The height can not be reduced like closing this Maxxair unit

Q) Also, did you have to replace the one above the shower?
A) Replacing the shower vent is next on my list. The plastic parts are brittle from sun exposure. I am putting in a replacement that is exactly the same as the one that I'm taking out.

Kentuckian wrote:ggeorgiagirl,

Q) Can you open it while you are driving?
A) The lift mechanism is well made and appears pretty robust. Slow speeds, no problem. However, I don't drive with it open at fast speeds as I don't want to risk wear and tear with the wind beating on the plastic lid. When rolling, I think opening the B190's side windows is a lower drag ventilation option.

FF does say their fans are okay to have open while driving. I've done it a couple times, at highway speeds.

Q) Just out of curosity, why did you pick this one (instead of the Fan Tastic fan)?
A) Because this model vents from the underneath side of the hood. So it can be open even when it is raining. The Fan Tastic Fan models that I have seen have open sides allowing rain to splash or blow in when in the open position. I have seen covered shells that can be mounted over the top of the Fan Tastic Fan. But, that means that the height of your roof line is permenantly taller. The height can not be reduced like closing this Maxxair unit

The higher-level FF units have rain sensors that will close if they detect rain. But the Maxxair can be kept on even if it is raining, so I think it wins that battle. Our trailer has the cover over the FF...I generally hate those covers, but I've found them very useful for allowing the trailer to air out at home while we aren't using it.

I've heard nothing but good about both brands. But I know firsthand that FF's service is excellent - if you call them, they'll usually ship parts for the cost of shipping. I do not have experience with Maxxair's service.

Looks nice! I have the same crappy one that you had and would like something a little more versitle. What size or SKU number did you get?

B)

mtnmanb
Here is a features list of the Maxxair Corp. fans. I bought the MaxxFan Deluxe Model 5100K for white lid and manual open. Although, the electric opening lid with remote control looked like a lot of fun! <smile>

Skater
I notice that the MaxxFan opening mechanism has two supports connecting the lid to the fan chassis. (Refer to the fourth photo in this discussion thread.) That looks pretty robust to me. I'd say it would be fairly stable at higher speeds. I just haven't had a need to test it.

Kentuckian wrote:I notice that the MaxxFan opening mechanism has two supports connecting the lid to the fan chassis. (Refer to the fourth photo in this discussion thread.) That looks pretty robust to me. I'd say it would be fairly stable at higher speeds. I just haven't had a need to test it.

I didn't mean to imply that MaxxFans couldn't be opened at highway speeds, just that FF's owners manual says it's fine. It's probably okay for Maxxfans too.

Thanks! Looks like it's around 230 on Amazon. I'll be using this in the winter and will have a lot of moisture in the van to get rid of (wet clothes and ski gear).

Sorry for all the questions. But was it difficult to take the old one out? It looks like you had a lot of rust built up on the old one. Did you seal the new one with silicon on the screws? Were they in the same place as the old screws? I'm guessing that you had to crawl on the roof to do the work, correct?

I'm just trying to figure out if I can do this on my own or need to take it to a shop. My DIY skills aren't the best. Thx!

B)

Q) But was it difficult to take the old one out?
A) Removal is easy. Installation has a lot of steps. But, each individual step is not that difficult. The easy part is that the new fan is basically just a drop in replacement for the old one. Your roof hole and wires are already in place.

Q) Did you seal the new one with silicon on the screws? Were they in the same place as the old screws? I'm guessing that you had to crawl on the roof to do the work, correct?
A) No I did not use silicon. I used butyl rubber. My opinion is that it has much better adhesion properties than silicon.
A) Unfortunately, the screw holes are not in the same place.
A) Yes, most of the work is from on top of the roof. The roof is very strong. You aren’t going to fall through. But, if you are heavy and concentrate your weight too sharply you could crack the fiberglass which is potentially a bad thing. I weigh about 165lbs and had no problem thoughtfully walking on the roof. I suggest a soft sole shoe like tennis shoes. Make sure they are clean and free of gravel each time you go up the ladder. Main thing is to be smart about distributing your weight. For example, I used a small plywood board to kneel on.


I am pretty comfortable doing such projects. So for me this is a doable Saturday afternoon job. I’ll share my steps and you can judge for yourself whether or not you want to tackle it. I like doing things like this myself because at least I know how it was done!

These are the main steps from my installation. For a complete instruction, you would combine my steps with the instructions that come with the new vent. Your’s or other’s installation methods might be better than mine <smile> :

Turn off the 12volt power at the RV’s breaker box.

Scrape off the sealant from the screw heads and remove the screws holding the vent to the roof. Remove the old vent's interior beauty ring.

Use a 1" wide thin putty knife to slide in between the roof and the vent’s mounting flange, cutting the old sealant around the perimeter of the vent. Keep the blade flat against the roof to prevent gouging the fiberglass roof. Lift out the old vent taking care to disconnect the power wires. Unscrew the wire nut on one wire. Separate the vent wire and RV wire and screw the wire nut back on the wire that is connected to the RV. Place the wire out of the way. Repeat for the other wire.

Scrape off any remaining thick sealant on the roof. Use suitable oil free solvent to clean off any remaining thin sealant still on the roof. I used a rag lightly dampened with acetone. Take care as acetone will dissolve plastic and many paints. Its fine on a lightly dampened rag on the roof around the hole. Don't use it on the new fan's plastic.

Next test fit the new vent in the hole and at the same time test fit the new interior beauty ring. I had to make a thin trim cut on the interior header to open the hole slightly. Make sure the wires are out of the way if you have to cut something.

With the new vent in the hole, mark the location for each of the new vent’s flange screw holes with a pencil. Remove the vent and drill small pilot holes where the new screws will go. This reduces the risk of cracking the fiberglass when driving the new screws. Clean off all dust and wipe the mating surfaces of the roof and vent with rubbing alcohol to remove any wax or oil that might reduce adhesion of the sealant.

Fill the old screw holes with a little butyl rubber from a caulking gun. I then mounted 3/4" butyl rubber tape on the underside of the vent's mounting flange where it would contact the roof. Make sure that there are no gaps in the butyl rubber ring that you have installed. This could be a potential leak path.
I installed the vent and reconnected the power wires. Check that you can still install the interior beauty ring with the wires connected. This may take a little effort to route the wires in the right place.

Double check to make sure the butyl rubber tape stayed in place and will act as a continuous gasket around the perimeter of the vent’s flange. I then drove in the new mounting flange screws. Your goal is to drive the screws only until they firmly compress the butyl tape. You do not have to drive the screws all the way to where the vent’s flange is touching the roof. Do this like tightening lug nuts when changing a tire. Drive a screw just until it touches the new vent’s flange. Move to the opposite side and drive the next screw until is just touches the vent’s flange. Go back and forth on opposing sides in a four corner pattern seating the screws evenly. This method will prevent you from squeezing out all the sealant unevenly from one side before the other. I squeezed the butyl tape to about 25-50% of its original thickness.

I sealed the edge of the vent to roof joint with butyl rubber in a caulking gun. I then used the same butyl rubber in the caulking gun to seal over the heads of all the mounting screws. Double check the roof to vent flange joint and screw heads to make sure that there are no gaps in your butyl rubber caulking job. This is your primary water leak barrier.

Follow the vent’s instructions on cutting the interior beauty ring, install same, turn on the power, confirm proper function of the fan and pat yourself on the back for a job well done!

Most local and web RV supply stores stock butyl tape and caulk. Screws come with the vent.