What
is important to understand is that installing a suction side filter will
not help your new compressor or prevent it from failing again. In fact, from
the actual vehicles we have seen and diagnosed, it is very common for that
suction side filter to come loose in the suction line and get ‘sucked
into’ the compressor. When that happens, the new replacement compressor
just installed suffers immediate and catastrophic failure without any warning.
Understand
that the only purpose of the suction filter is to prevent debris from being
pushed up the suction line in the event of a compressor failure. After the
first compressor failure, the suction line filter does nothing to protect
your new compressor. That’s because it’s on the suction side of
the system where the refrigerant is in it’s vapor form and does not
carry debris or contamination that may be left in the system. In short, there
is no debris to trap!
The
low side of the A/C system starts at the expansion valve or orifice tube.
Because of those components design, it’s almost impossible to have debris
travel past the filter screens on the orifice tube or through the opening
of the expansion valve. (That opening is only a few thousandths of an inch!)
So it’s most likely all contamination is stopped right there. However,
if by chance the contamination got past the orifice tube, understand that
liquid refrigerant entering the bottom of the evaporator must boil before
it leaves the top outlet of the evaporator. Yes, in the evaporator, the
refrigerant absorbs heat and boils or changes state to vapor before exiting
the evaporator.
Now,
just like contaminated water, when that water boils, all of the contaminants
remain in the liquid. They are not carried by the vapor. The same physics
apply with the liquid refrigerant. When it boils, the vapor does not carry
the contaminants. They remain in the liquid. In this case, in the bottom
of the evaporator. Now, even if contamination could get out of the evaporator,
most systems utilize low side accumulators that force any remaining liquid
refrigerant to the bottom, to circulate around the desiccant. The only exit
from the accumulator is for vapor refrigerant, and that exit is at the top
of the accumulator. In fact, what happens is that the compressor suction
‘pulls’ the refrigerant out of the accumulator as a vapor through
the top outlet. Once again, contamination will not be carried by that vapor.
Therefore,
installing a suction line filter will not (and can not) trap any of the harmful
debris that will help to prevent another compressor failures. Why? Because
the debris isn’t in the suction side of the A/C system! For those reasons
we have determined that installing a suction line filter is the equivalent
to taking your accordion deer hunting. It just doesn’t make any sense.
The
proper in-line A/C filter
to install is one that will trap any remaining debris and still allow refrigerant
and oil to flow through the system. In order to do that, you must install
an in-line filter in the liquid line, BEFORE the orifice tube. Doing that
will assure that the orifice tube remains clean and that refrigerant and
oil will continue to flow through the system, to the compressor where it’s
required.
The
simple technology behind this is as follows. First of all, understand that
it takes less than 1/10th of a teaspoon of debris to plug an orifice tube
or expansion valve. When that happens, refrigerant and oil flow to the compressor
is restricted. When you reduce the refrigerant flow, the low side of the
A/C system goes into a superheat condition. That basically means that the
refrigerant is absorbing more heat than it should be. So now, the refrigerant
returning to the compressor is not cool. It’s warm. That effectively
eliminates any cooling that the compressor would receive.
Along
with the reduced flow of refrigerant, it’s important to understand that
the oil flow to the compressor is also reduced because the oil for the compressor
is carried by the refrigerant. That now means your A/C system is trying to
operate but the compressor is not getting proper cooling or lubrication.
How long do you think it will last?
Install
quality in-line A/C filters
that work on the Liquid Line of the A/C system and are designed to trap and
hold excess debris while still allowing the refrigerant and oil to flow through
the orifice tube or expansion valve. That way, you are helping to prevent
another compressor failure. |
This
was probably one of the best books on recharging air conditioning that I
have seen...
