The wall registers in a Newtown block house are blowing, but not cold: a cause table in order of what it costs to wait

Why this page is about block houses

Palatka’s housing from the 1950s through the 1970s is concrete block on a slab: Newtown, the US 17 corridor, parts of Palatka Heights. These houses share a layout. The air handler is in a hall closet or a utility room off the carport, the ducts run through a low attic that reaches 130 degrees in July, the return is one grille in the hallway, and the outdoor unit sits on a pad beside the carport. When one of them starts blowing warm, the list of causes is short and well known. Here it is, ordered by what each one costs if you keep running the system instead of calling.

The cause table

What you notice at the house	What is usually wrong	What waiting costs	How urgent
Outdoor fan not turning, unit humming or clicking	Failed run capacitor; sometimes the fan motor	A compressor trying to start against a dead capacitor overheats; a week of this can take the compressor with it	Shut it off and call today
Outdoor unit silent, indoor fan running	Tripped breaker, failed contactor, or a safety switch	Little, if it stays off; a lot if the breaker is reset repeatedly	Call today
Ice on the copper line at the handler	Low refrigerant or airflow restriction	Each freeze-thaw cycle floods the pan and stresses the compressor	Turn off cooling, run fan, call
Air at the register barely moving	Clogged filter, iced coil, or failing blower	Starved airflow freezes the coil and finishes the blower motor	Check the filter first; then call
Cool air at some registers, warm at others	Duct disconnected or crushed in the attic	You cool the attic all summer on an FPL bill	Call this week
Cools in the morning, loses ground after 2 p.m.	Undersized or weak system, dirty outdoor coil, low charge	Highest bills of the year for the least comfort	Call this week

Deeper notes on the top three

The capacitor. The humming outdoor unit with a motionless fan is the single most common warm-air call in Putnam County from June to September. The run capacitor is a small cylinder that gives the fan and compressor motors their start, and heat kills it. Rural power quality matters here: a summer of brownouts and lightning-related surges on the lines around Palatka ages capacitors faster than a stable grid would. The part is inexpensive and on the truck. The reason to shut the system off while you wait is that a compressor trying to start without it draws high current and heats up, and that is how a cheap part becomes an expensive one.

Low refrigerant. A system that is low on charge still blows air; the air is just not cold. The charge did not evaporate; it leaked, usually at the evaporator coil or a line-set fitting, and on a twenty-year-old system a coil leak is where repair-or-replace gets discussed. Topping off without finding the leak is a repeat call in August. We find the leak first.

The duct in the attic. Block houses here often have original flex or fiberglass duct that has sagged, split or pulled off a boot in a 130-degree attic. The system cools perfectly; the cooling goes into the attic. The sign is a room that never cools while the hall is fine, and an electric bill that does not match the comfort.

Call for same-day diagnosis

When to shut it off and call

Shut the system off entirely, or switch to fan-only, when the outdoor fan is not turning, when there is ice on the lines, or when the breaker has tripped once already. Keep it running, and call this week rather than tonight, when the problem is a room or two that never cools or an afternoon fade on the hottest days.

In either case, do two things first: check the filter, because a filter packed with spring pollen and mill dust is the cheapest cause of weak air in Palatka, and check the thermostat for a dead battery or an accidental switch to heat.

What the visit involves

We dispatch from the Palm Coast headquarters, about 51 minutes down SR 100, and the truck carries capacitors, contactors, fan motors and the common refrigerants. The technician tests the electrical side first, checks airflow and the filter, reads pressures and temperatures on the refrigerant side, and looks at the ducts if the symptom points there. You get the diagnosis and the price before any part goes in, and there is no after-hours charge: a Sunday evening in Newtown costs what a Tuesday morning does.