Salvaging a Caframo fan with a failed control board

[GILow]

Hi all,

A few months back I noticed four Caframo 12 volt fans in the dumpster at the marina. I was surprised because they looked very clean and straight. But looking closer I saw all had masking tape notes saying they were not working and two had wires sticking out holes in the case.

Also in the bin were the boxes for four new fans which was a bonus as the boxes still had the mounting plates.

I grabbed the lot and when I had some time checked them out. None worked, and it was soon clear that all had failed control boards. The wires through the side were attempts to bypass the speed/power switches.

So, after a discussion here on CF I finally got around to ordering some PWM DC motor controllers on EBay @ AU$2.45 each.

I chose the sort with the rotating knob that doubles as an on/off switch and what follows are some photos of installing the controllers for anyone who has also had problems with the power control boards. The job takes less than ten minutes per fan (once you've found the tools you need, namely a couple of Phillips screwdrivers, wire cutters, wire strippers, a soldering iron for the purists and a drill)

The main trick is to strip out all of the failed control circuitry while keeping the red and black fan motor feed wires as long as possible. It is also important to drill the hole for the control knob far enough from the base plate to clear the connection box in the plate but not so far that you can't get the PWM control board into the tapered case near the fan hinge.

Good luck, and FWIW, I've found the "infinitely variable" speed control greatly superior to the old three speed settings. You do lose the timer function, but I've never used it so I'm not sure if that's going to be an issue for anyone.

[JPA Cate]

A+ for effective dumpster diving!

Looks super.

Ann

[Lepke]

Lots of fans fail because the bearings run out of lube. If you open them up and reoil the bearings they work fine. I've got one my dad bought from the 1950s.

I use similar motor speed controllers from eBay on bilge blowers used to continuously vent my bilge areas at very low speed to keep the boat smell away. 83' wood boat.

[Jim Cate]

good one, Matt. I took a similar route with a high end (3+$) PWM controller box to run a small muffin fan we use to circulate the hot air above our diesel heater. One caveat: ours seems to generate a bit of HF RFI. Won't likely be an issue for you, because the Calframo fans are pretty noisy themselves, and you'll likely turn them off whilst on the air.

One can but wonder what happened to destroy all four fans in a short time frame?

Jim

[GILow]

Originally Posted by Jim Cate

good one, Matt. I took a similar route with a high end (3+$) PWM controller box to run a small muffin fan we use to circulate the hot air above our diesel heater. One caveat: ours seems to generate a bit of HF RFI. Won't likely be an issue for you, because the Calframo fans are pretty noisy themselves, and you'll likely turn them off whilst on the air.

One can but wonder what happened to destroy all four fans in a short time frame?

Jim

I’ll do the same HF test I did at your suggestion a while back with the solar regulators, and report back.

As for the fans, I thought maybe a lightening strike, and then I realised they’d come from a Crowther 582, a boat my son once remarked of.. “Sh-t! Here come the bl—dy Nimitz!”. They might have 50 of these fans aboard, 4 probably represents less than a 10% failure rate over time.

[svMarite]

Great stuff, thanks for sharing that

[Draughty]

Yeah Caframo fans; great design, pity about the execution.

There's a few marine equipment companies around that reckon design is everything (think Crewsaver; who promote an inflatable lifejacket/harness with a dedicated PLB pocket which won't fit any PLB available in the world).
Testing is everything!

Rgds all.

[NevilleCat]

Originally Posted by Jim Cate

good one, Matt. I took a similar route with a high end (3+$) PWM controller box to run a small muffin fan we use to circulate the hot air above our diesel heater. One caveat: ours seems to generate a bit of HF RFI. Won't likely be an issue for you, because the Calframo fans are pretty noisy themselves, and you'll likely turn them off whilst on the air.

One can but wonder what happened to destroy all four fans in a short time frame?

Jim

Interesting you find the Caframo fans noisy Jim. The Sirocco's seem to be generally regarded as the quietest around I thought?
Or did you mean RF noise?

[GILow]

Originally Posted by NevilleCat

Interesting you find the Caframo fans noisy Jim. The Sirocco's seem to be generally regarded as the quietest around I thought?

Or did you mean RF noise?

Yeah, the only noise Jim can hear is in the HF band. He wouldn’t hear a bandsaw running a meter away.

[Bundyon]

Bloody good score, I remember reading your initial post when you found them. We live in a throw away world, not too many people try to fix things anymore, it's remove & replace! I'm an old school mechanic, try and salvage/ fix first! ��

[Thumbs Up]

I have had Caframos replaced under warranty. They were very interested in the failure modes. The new Scirrocco fans are a little different. I think that they worked out some the kinks. I built a nice hybrid using parts from a few different Caframos. Works great but don't stick your finger in it it has hard blades!

[mikedefieslife]

Nice.

I took apart a failed Bora, where was no circuit board in it though from what I could see. It also used a 36v motor which I found interesting.

[OBT]

Have the same issue with fans. One I modified with a 12 volt computer fan. Quiet as a church.

Cheers and good on ya.

[Jim Cate]

Originally Posted by GILow

Yeah, the only noise Jim can hear is in the HF band. He wouldn’t hear a bandsaw running a meter away.

Bandsaw??? What bandsaw??? I don't hear no steenkin' bandsaw......

Jim

PS Yep, I meant RFI noise... and they are a bit on the noisy side. Acoustically not so bad for the amount of air they move. We have the older ones with simple two speed switching, and they have been quite reliable, other than the blades eventually failing. My main complaint about them is that the switch placement on the back of the motor makes it easy to get your hand into the blade whilst switching on or off.

[GILow]

Originally Posted by Jim Cate

Bandsaw??? What bandsaw??? I don't hear no steenkin' bandsaw......

Jim

PS Yep, I meant RFI noise... and they are a bit on the noisy side. Acoustically not so bad for the amount of air they move. We have the older ones with simple two speed switching, and they have been quite reliable, other than the blades eventually failing. My main complaint about them is that the switch placement on the back of the motor makes it easy to get your hand into the blade whilst switching on or off.

I wonder if the RF noise was coming from the motor or the speed controller?

There do seem to have been a lot of changes to the circuitry over time. The four failed fans had three different circuit boards between them, and each was different again to the three Sirocco II fans I already had on board, and yet the fans themselves seem nearly identical.