On 12 Feb 2007 05:49:46 -0800, wrote:

On Feb 11, 11:31 pm, malam wrote:
I installed a General Aire Model 1042L Humidifier 4 years ago with the
bypass 6 in duct installed in the return air duct. I was just
wondering the effect of having the bypass line in the return air on
the air filter which is downstream of the bypass.

Questions: - 1. Will the moist air drawn through the air filter not
affect the operation of the filter?
- 2. Will the moisture be retained by the filter?

The reason why I when this route is that my heater supply duct is very
narrow about 5 in (which is too narrow for the 6in bypass line). The
duct is 5 in high by 20 in wide.

Thanks.

I guess the first question is what kind of filter? If it's the
disposable kind, I doubt the extra moisture will be a problem for the
filter. If it's electronic, I'd read the manual or contact the
manufacturer.

I've never been a fan of the bypass type humdidifiers for 2 reasons.
One is it reduces the capacity of the blower. Second is, someone has
to remember to close off the bypass during AC season, or it will
reduce the blower capacity during summer too. And third, related to
your concern, I've never thought it was a good idea to send humid air
through the furnace blower, hot heat exchanger, etc. With a self
powered unit, the humid air goes out the hot air plenum and never into
the furnace. I've never seen any actual data or reports however, that
say the bypass models cause problems though.

Thanks, I've been trying to rationalize the way the installation was
done for a while,but had no reason to doubt the method. However,
lately, I kind of wonder. I am going to try and explore the
possibility of installing the 6 in bypass line either at the top or
bottom of the heated air duct line. That way the bypass is returned
back into the same line, maybe some loss within the humidifier unit
itself. Although the height of the duct is narrow, it should be ok
to mount the line either at the top or at the bottom wider section. I
favour the bottom since any debris will fall back info the elbow.
(??). It will also be after the filtration and heating of the air. My
air filter is the paper accordion General Filter AC1 type. I also have
a UV bulb unit just before the filter.