Roseholme Cottage is an old house. It's been upgraded through the years, but it was designed to have a roaring coal fire in the basement furnace all winter and have the windows opened at top and bottom in the hottest summer months.
It wasn't designed for air-conditioning. The system copes pretty well nevertheless, right up to about 95°F outdoors and then it...doesn't. That's what happened Friday evening. It crept up slowly; doing the dinner dishes, I realized the house was either unusually warm or I was. (I'm old. It happens.) A look at the thermostat showed the house was four degrees above the set point and airflow from the registers felt reduced. So I shut off the cooling and left the fan running while I checked the furnace for water leaks. Nothing, but the box around the A-coil was colder than usual. I changed the filter on general principles, but the old one didn't appear to be very dirty. I had been self-indulgent with the setting, going as low as 73° in the morning, and that was clearly asking too much during extreme heat.
A couple of hours with the fan on and indoor temperatures slowly rising got airflow back to normal, which meant the A-coil was clear of ice. I ran the cooling for fifteen minutes and set the thermostat a degree above the resulting temperature: 82°.
That may sound terrible, but it's not: as hot as it was outside, the system was running enough to bring the humidity way down and with the blower set to run all the time, the house was comfortable enough for me to sleep under the covers.
Saturday was as least as hot as Friday. I paid attention to the airflow and temperature, but it never froze up. Sunday was better and by evening, I stared bringing the temperature down. By bedtime, it was back at 75°, and I'll leave it there until the next hot spell.
BUILDING A 1:1 BALUN
3 years ago