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Fantastic Fan open/close


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Fantastic Fan will no longer open or close with the motor.  If I manually crank it up it will run.  If I dampen the rain sensor the fan will turn off but will not close the lid.  I took the up/down motor out and jumped it to the 12v battery and it runs slowly as I guess it is supposed to as it is marked 4 RPM.  Measure the voltage coming to the motor wires and it seems to read about 4 volts all the time.  No change when I start or stop the fan from the control panel.  Where to look next?

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At a couple of random times I've heard the motor turn for a couple of seconds and then quit, and this was long after and not associated with any control panel actions.   Kinda surprised me one night... BTW, as I must open and close it manually, the motor is disengaged from the spline at the moment, so even under a no load situation it doesn't function.  The exhaust fan (blades) runs fine, throttles up and down via the control panel just fine.  As I crank it open manually the outside switch breaks contact with the lid and the exhaust fan motor runs normally.  It is the lid lift open/close motor that it's the problem.  As stated earlier, removed the motor and jumped to battery terminals it runs.  Why would the lift motor wires seem to have a constant 4 volts?  Is there another logic board burried some place else?  Seems to be only two wires from the cabinet control panel that disappear into a wire loom heading into the wall then presumably ceiling someplace.  Implying a serial communication to something?  Control panel will control the fan blade speed just fine.  There is a little age discoloring on one edge of the rain sensor, but it seems detect water dampness and turns off the blades when damp and resumes the blades when it dries out.  But it used to also trigger the open/closer motor too.  And the rain switch when set to off ingores any water/dampness ... is not detected and had no effect on the blade speed.  When "on" the dampness turns off the fan blades.  The blades seem to ramp up to have full voltage.  There is no binding when I disengage the lift motor and crank the lid manually.

My apologies for restating the symptoms again, but I guess my first statement wasn't clear.

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I have had the same problem and noticed it seems to be weather related. Works fine when the roof is cool but not when it’s hot. I’ve read in other forums that these fans are known to get stuck in the tacky weather sealant when it gets warm. You may want to inspect yours for overlapping sealant that may be sticking to the lid.

I haven’t had a chance to inspect mine yet but it is on the “to-do” list.


Good luck!

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We are on our third Class A.  All had fan-tastic fan covers installed on all our rigs.  You did not mention if you had covers over your fans.  Our present coach has the remote fans with the rain sensors because that is they way they come.  The fan covers allow the fans to stay open and working without any rain coming in.  The covers also keep any of the fans workings out of the elements.

Even with the covers over the fans, the movable fan lid can stick especially in hot weather.  Once a year I go up on the roof of our coach, flip up the fan cover, open the fan lid and wipe down the fan lid rubber seal with rubber seal spray leaving no residue.  Works for me.

Good luck, stay safe, stay well.

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As your fan opens there is a plunger type ground switch that pops up as the cover rises. This plunger switch can get corrosion on it and create a bad ground for the fan, causing erratic operation.  Remove the switch and clean the corrosion off -usually a white appearing deposit. 

Chet P

04 SIG Castle IV

 

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  • 5 months later...

It has been a while and it took me a while to fix it as the fan worked manually and at random times would actually open and close the dome lid from the control panel. 

Anyway, FWIW in case somebody else has a problem with an erratic Fantastic Vent lift motor operation:  After digging around the trim in the ceiling I removed the control board and tried cleaning the contacts.  No change but I kinda thought it had to be that control board from swapping parts.  The Electrolytic caps looked fine, but back in my mind I was thinking it was probably them failing.  Anyway, I couldn't sucessfully locate the exact MC104C Long board but tried a MC104D short board (circuit design and components quite a bit different and much shorter but still had the same connector layout along the two edges and mounting screw locations).  That fixed the problem.  Even tho the new to me board (made in 2015) came with a new rain sensor, I just plugged in the old rain sensor first to minimize the work required to get the new sensor up to the roof and rivited in, but luckily the old rain sensor still worked fine with the new board (put water on it and it closed the fan dome as it should).  There is one minor operational change between this D board from my original C board, and that is when I use the control panel to turn the fan off and lower the dome, the old (C long) board (verified as I still have an identical functioning vent in the kitchen) immediately turns off the fan blades as the lift motor retracts the dome lid whereas the newer D board keeps the fan blades running until the dome lid retracts enough to contact the plunger.  Both boards seem to drive the lift/retract motor until it senses a high current draw from the dome hitting the travel limit.

By the way, be cautious of what sites pop up on google searching as one of my first hits for an instock old C long style control board likely turned out to be a scam site, but PayPal resolved the dispute relatively quickly including the initial over charge from the listed price, and the vendor claim of even shipping it from Las Vegas and delivering it to my city even before I ordered it, (according to the tracking number the vendor provided).  PayPal did the full refund with no hassels.  Later I did a little IP address verification where it showed to be an offshore venture with dummy US contact info. YMMV  Also shortly after that I started getting more scam phishing phone calls on the phone number used in that problematic purchase order.  Coincidence??

Anyway, it has all worked out in the end.

PXL_20201023_211016907.jpg

PXL_20201121_211854105.jpg

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Circuit boards are in my wheel house and a problem that is often encountered with designs that have longevity is the inability to source the components after the design ages. The old circuit board above is mostly discrete, thru hole components that look to be over 20 years past their introduction to the market. A manufacturing house would not be able to obtain a reliable source to continue manufacturing that board design. The board at the bottom has a large percentage of surface mount components and looks to have either a microprocessor or a programmable logic device to provide control functions. I suspect the company was forced to up grade the board even through the old one worked just fine.

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2009 Dynasty. That might be my problem too with the circuit board. It will turn on and off on its own and at times will blow a fuse. I noticed that if I walked on the roof directly in front of it the fan would come on then if I took my foot off that spot it would stop. That was last summer. Now just before putting it away if reinstalled the fuse for it (it had blown for the 5th time so I just left it out) and now it works with no issues. But now the rear fan is doing the same thing. I’m wondering if there is a little moisture getting in and causing it to corrode the board? I won’t look at it unti next spring when I take it out of heated storage here in Minnesota. But at least this gives a direction to look? 

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I have an unusual  problem but similar to what has been discussed.  My bathroom fan lid will open correctly, the fan will run like it is supposed to but when I turn the fan to "off" the fan will shut down but the lid will not close.  However, if I reach up and remove the fuse, then replace it the lid will close.  It has been driving me nuts for about 5 years.  I replaced the control panel but no help.  Is the circuit board that is referred to in this thread the same as the control panel or is it another board hidden away somewhere.  D I have to remove the whole fan to get to it??

 

Thanks,  Bob L, 08 dynasty

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12 minutes ago, Rich Cutler said:

I can guarantee that Fantastic will tell you how to correct the problem with a call or email.  More than likely, they will send parts free of charge, if needed.  They are Fantastic to work with, pun intended.

Rich Cutler

'06 Windsor

Hi Rich,

Things have changed a LOT with the company since they've changed hands twice.  4 or 5 years ago I had a problem with the lift rail cracking off the dome lid on one fan.  Called Fantastic Vent not only did they offer to send a new lid (just pay for however I wanted it shipped ... air overnight, ground, USPS, etc) but they also said sometimes the lift arm itself or roll pin gave problems and included those for free too.  I mentioned that I had two identical vents and they doubled everything in the shipment.  Just pay however I wanted it shipped, and it was shipped that same day.

So now they have gone through Atwood and Dometic ownership.    Got through to them via a long phone tree and several transfers.  Lady said that was an old out of production unit, didn't any parts for it.  Thought the more recent MC104D should work but couldn't provide one for any price.  Suggested one of their distributors whom I called, but they looked and said they could not get nor find a reference nor an ordering method even for the internal part number Dometic gave me.

IMHO, The new ownership is helpful and had info on the old unit, but not like the old company used to be...as is the case with a lot of mergers and acquisitions.

In the end, I got enough info to get my vent working satisfactory and didn't have to try to replace it with the newer model that has the hand held wireless remote.  Information I got from eTrailer and other places seem to indicate the newer model won't reopen automatically when the rain stops.  I haven't seen if the replacement MC104D board I got includes that feature or not as the coach is in storage now and I didn't wait for the rain sensor to dry out by itself when I was testing it.

FWIW

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Boy, that is sad to hear.  I had the best experiences.  Haven't had problems for many years.  Being a '06 coach guess all my problems have worked themselves out.  My biggest issue was the hatch sticking down on the seal.  They replaced all the seals.  

It is like my repair location says, "Do not get a new coach, you will only get trouble.  You have the best they made."  My last upgrade was a Samsung RF18, should have done it years ago.  Got rid if the potential fire hazard NoCold.   One before that to get rid of all the carpet for wood floors, including the slide.  Kept the tile in the bath and kitchen.

Rich Cutler

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17 hours ago, Bobbyboy said:

I have an unusual  problem but similar to what has been discussed.  My bathroom fan lid will open correctly, the fan will run like it is supposed to but when I turn the fan to "off" the fan will shut down but the lid will not close.  However, if I reach up and remove the fuse, then replace it the lid will close.  It has been driving me nuts for about 5 years.  I replaced the control panel but no help.  Is the circuit board that is referred to in this thread the same as the control panel or is it another board hidden away somewhere.  D I have to remove the whole fan to get to it??

 

Thanks,  Bob L, 08 dynasty

Hi Bob,

No, just remove the trim from the inside of the opening. Remove the fuse (for safety), a screw to remove the manual crank knob (makes it easier to reach the other screw especially when trying to put it back up), two screws for the lift motor cover and the lift motor drops in your hand, three screws around the edges then wiggle it down dragging all the wires.  Couple of wires wrap around the entire trim so unclipping them first drops it down s little further making it easier to unplug the other wires. When putting it back up I also removed the 8-10 screws on the screen so I could reach through to keep the wires tucked as I put it back in place.

Like you, I did experience times when removing the fuse, waiting a minute, and reinserting the fuse sometimes allowed the lift motor to work again for a short while.  I was thinking either noise in the power supply or output transistor in an unstable state causing that weird 4 volt reading I sometimes got.

Al

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