On 2009-02-26, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Ignoramus19022 fired this volley
in :

So, my question is, is that normal behavior at all, do heat
exchangers
add quite a bit to "obstruction", or is there possibly something
with
this air dryer.

If you think that it is a problem, and you have seen it before, I
would love to know what might cause an obstruction like that, maybe
a
bug that crawled in there.

Think of an air dryer as simply a refrigerated pipe. Ideally, it
should cause no more obstruction or friction resistance to flow than
would any piece of pipe that size (with numerous bends in it).

If a 25CFM dryer can't handle a 1/4" fitting, there's obviously
"stuff" in the line -- which is _probably_ why it was offered for sale
in the first place.

Bugs, maybe. Corrosion is likely if the exchanger isn't stainless
steel. Try reversing the flow at a high pressure, and open the
"inlet" as wide as the fitting will allow. You might blow the
obstruction out the way it came in.

The reason why I suspect bugs is that I kept it outside for 2.5 months.

At least you confirm that something bogus is going on.

I did already try reversing air and it did not help.

There are probably more bends in the lines than would permit you to
"roto-rooter" it out. But if the lines are made of stainless, you
could conceivably clean them with acid OR a strong base. Acid if it's
mineral, base if it's organic.

We had a combination dryer/water chiller at the injection molding
outfit I worked for. It had replaceable exchanger coils for each
purpose, immersed in a brine bath that was itself chilled by the
actual refrigeration evaporator. That was a good design for long-term
maintainability.

I will take it apart and see, I think.

Thanks Lloyd, now I at least know that I have a problem.

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