Date: Sun, 28 Aug 2016 17:25:25 -0700
Reply-To: Alistair Bell <albell@SHAW.CA>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Alistair Bell <albell@SHAW.CA>
Subject: Re: Dometic fridge (external) fan replacement...
In-Reply-To: <5e1dc97d-70b4-e1e7-eb6e-ebf6cd5a3602@williamsitconsulting.com>
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I've done pretty well all of the suggestions mentioned so far. When my stock fan failed way back in the early noughts, I replaced it with a small muffin fan on a bracket at the stock fan location. It worked ok, worked well enough. It cycled on and off often than the stock fan though.
I added a fan to the side vent adjacent to the cubbies. I used that on and off in the high summer. I'm sure it helped but it obviously wasn't getting hot air out of the van.
I added the city water port fan mod and although I didn't have data to support this, I feel that it helped a fair bit. You could feel warm air coming out of the port.
A few years ago I added another muffin fan, on the middle series of fins on the back.
What that did was to aggravate the cycle time. The fan would cycle on and off more often. Annoyingly so I thought.
Recently I removed both muffin fans and put the stock fan blade on a salvaged 12 v motor, a little larger and faster turning than the stock motor. This is working out fine, the frequent cycling has stopped, the fan seems to come on less often.
I used to think that a muffin fan was a good choice, I changed my mind, but yet other folk have had good results with such a fan. I think it very much depends on the type of muffin fan. There are new designs with cleverly shaped blades that move a lot of air with little noise.
What I also did recently but I again have no hard data to support any conclusions, was to wrap the fridge exhaust pipe with a couple of layers of aluminum foil (loosely wrapped with lots of crinkles) where it comes out of the insulated shield at the back of the fridge and up to the vent in the wall.
It's only a short section but I really do think that the insulation is working to reduce the amount of heat radiated from the pipe and thus reduce the amount of heat back at the fins.
I've been toying with the idea of buying one of those small thermo controls for the fan. The inexpensive ones have adjustable set point and some sort of dead zone control. The more expensive ones have PID control. It's very much over kill and probably not worth it, but a PID controlled fan would be another fun thing to have , if you like that kind of thing :-)
Alistair
> On Aug 27, 2016, at 11:08 PM, Steve Williams <steve@WILLIAMSITCONSULTING.COM> wrote:
>
> Hi,
>
> The fan on my Dometic fridge started squealing quite loudly when it
> starts up. Not so great in the middle of the night ;)
>
> I am just going to replace it with a computer fan. I've got a few old
> PC's that I can butcher. I figure I can cut up the metal from a power
> supply to make a suitable bracket. Looking at the orientation of the
> existing fan, I'll have to make a 90 degree bracket which isn't too
> challenging if I use a power supply to cut up.
>
> I can't be the only person that's had to do this. What size fan (cfm?)
> did you use? What RPM did you use? I'm going to try to find a fairly
> quiet fan, but really don't know what the cooling capacity should be.
>
> Thanks,
> Steve Williams
