Thursday, March 25, 2021

Semi-Smart Machine

      We -- by which I mean our Facilities guy and his subcontractor -- installed one of those big, portable air-conditioners at the North Campus earlier this week, to help an ailing cooling system limp along for a few more months before we have to take it out behind the barn and do it mercy.

      The hulking gadget ran for two days and then shut itself down, displaying an incomprehensible glyph where it should show the temperature setting, plus a red indicator next to a legend reading "TANK FULL."

      While I did spend a wild moment wondering if it meant our Sherman had a full compliment of personnel aboard, in short order it dawned on me that the thing was trying to tell me that it was waterlogged.

      This was a mystery.  Facilities (et al) had carefully attached a long hose to the proper fitting, and routed it through the labyrinth to the basement sump fifty feet away and over a dozen feet lower.  Being of an investigative mind, I fetched a five-gallon pail and started to pry the drain hose from the barb.

      It started dribbling out grayish water long before the hose came free.  I had sudden doubts about the wisdom of  uncorking an unknown volume of water in a room filled with electrical machinery, shoved the hose back in place, sent a couple of e-mails to my boss and Facilities, fetched a lot of paper toweling and returned to the machine.

      Once the hose was off, it shot a jet of water mostly into the bucket (and the rest on me, yech), maybe a quart total, and began blowing out cold air like it was supposed to.  It even had the right temperature reading.  I put the hose back on, checked my e-mail, and discovered Facilities was en route and had asked me to do what I just did.

      I tried taking a wet-vac to the drain hose at the sump.  Nope!  Blocked.

      Back to the air-conditioner, which had shut down again.  Facilities showed up, and we eventually found a hidden blockage in the drain hose and cleared it.

      Those huge air-conditioners have a very small tank for water that condenses on the cooling coils and runs off.  Once it fills up, a pump empties it (permanently-installed systems usually just have a gravity feed, but portables may have to make water run uphill).  If the level gets too high or the pump sees too much back pressure, the cooling shuts off.  Oops!

1 comment:

Unknown said...

Similar issue with our gas forced-air furnace:

When it got cold in February, it wouldn't bring the house up to the temp set on the thermostat before shutting down with a blinky-light fault code on the main board.

The 'emergency' call got us put up to the top of the list for our gas-maintenance guy, and much to my embarrassment, the problem turned out to be the drain hose on the condensing furnace -- some sort of blockage (mouse, insect nest?) had partially blocked the hose, and just because I could blow thru the drain tube when I was doing my begrudging¹ maintenance, didn't mean that it wasn't a problem when the furnace was running full time and condensing lots of water. Each time, by the time the board did its time-out self-reset the liquid would have drained, so the furnace would start again, but not ever long enough at one time to get the house up to 68°F when it was -10° outside . . .

¹ our gas-guy will come nearly instantly when something is genuinely not working, but is very reticent to return calls for scheduling normal cleaning and maintenance. He's an excellent diagnostician and inexpensive though.