Sunday, February 5, 2017

Repairing an Ecofan

When we were first in the yurts, as fall deepened and we realized that the woodstove was not doing a very good job of heating the main yurt, let alone the back yurt, one of our first attempts at improvement was to purchase an "ecofan" - a small fan attached to a motor powered by a thermocouple wedged between a heavy steel base and a large heat sink.

While this was an improvement, at the time it wasn't enough to make the yurts comfortable by any reasonable stretch.  But that's another story.

When we moved into the cabin and began using the Baker's Choice woodstove, we brought it with us and it has been doing good duty moving a bit of the heat around the cabin these past three years.  It is often a good temperature indicator for the stove - we can tell just by how quickly it spins whether or not we have a good fire on.

Unfortunately a few days ago, I noticed that it spun up well, but then slowed down soon after, even though our stove top thermometer continued to show the stove warming up.

Over the next few days it began to behave erratically, not spinning at all, or spinning slowly, in spite of consistently warm fires.

At last I decided to try refurbishing it slightly.

The patient on the operating table.
Two screws to be removed.  Luckily I have a tiny ratchet set that should suffice.
First I removed the top heat sink.

The thermocouple exposed.
This allowed me to lift off the thermocouple.  I was surprised to discover that there was no thermal compound either above or below the thermocouple.  Thermal compound, or paste, is commonly found between computer chips and their heat sinks to ensure a good contact between the two metals.

No compound to be seen here either.
I put a dab of paste on top, and a little on the bottom.

Rats, not quite in the centre!
That's better!
And not bad looking front to back either.  :)  You can see a bit of the thermal paste squeezing out from the edges.
Placing it back on the stove, I was at first worried as nothing happened for a few minutes.  But then suddenly the fan kicked in and returned to a medium pace.

I checked it with an RPM meter and would guess that it's rotating at about 240 RPM.  Not sure if this is good or not; it doesn't seem as fast as previously, but at least it is consistent.  Hopefully it continues to work, even if it is in a reduced state.

Almost enough spin to be political!

Addendum:

After two days, I can report that it is still working, but I'd have to say definitely with a reduced speed.  Not enough to replace the fan altogether, but enough that I'll have to adjust my temperature vs. RPM estimates.

1 comment:

  1. Do not replace the whole fan. Home Hardware sells the part for about $12.00. We replace ours every year going on 12 years now on a cook stove.

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