Kyle wrote:
I have an Aprilaire humidifier hooked up to my furnace (natural gas)
and this morning I found water on the floor under the condensate pump
where the humidifier drains. The pump is attempting to run, but it
isn't draining - the reservoir is full and not emptying.

As it was 5.2 degrees (Fahrenheit, not Celsius) this morning and
hasn't been above freezing for a few days, I suspect the drain line,
which empties outside next to the a/c condenser unit, froze and is
blocked.

Question 1: any suggestions for how to thaw the line well, with little
risk of refreezing? (Sunshine is not a thawing option, as the line
comes out under the back deck and never sees direct light.)

Question 2: since the furnace is in the laundry room and there's no
other drain (such as a sink) in the room, is it a good idea to maybe
re-route the condensate drain into the pipe where the clothes washer
drains?

Yes to the second question if the laundry drain inlet is lower than the
humidifier outlet.