Extreme Cold Weather Equipment Tips

During cold snaps, arctic blasts, and major winter storms, the outdoor temperatures may go outside the ranges that mechanical systems are rated for in our region. The DC Metro Area is within ASHRAE Zone 4A that is rated for lows of 13℉.

We’ve listed the common equipment problems that happen during extreme cold and the red flags you’ll notice.  If you observe any of these warning signs during daytime hours when temperatures are above 13°F, they indicate that your system is already struggling. This means it is at high risk of failing once temperatures drop again overnight.

Refrigeration - common problems in colder weather with accumulation or snow and ice:

1. If the system is undercharged (doesn’t have enough refrigerant), the unit will not cool properly in low temperatures

2. The headmaster (Head Pressure Control Valve) is failing 

3. The condenser fan cycle switch is improperly set

4. The condenser is blocked by ice or snow - which will cause a failure 

     What you may notice

1. Temperature getting higher than normal during colder times or as temperatures drop

2. Spikes in the temperature of the unit(s) overnight or first thing in the morning

3. Excessive ice buildup on evaporators

4. Erratic temperature (works fine for a while them doesn’t seem to be working)

5. Unusual noise or vibrations from units 

Gas systems (HVAC, Boilers, and gas cooking equipment) - common issues in extreme cold: 

1. Gas meter may have moisture in it that freezes, causing the gas flow to shut off or operate below the necessary pressures needed to operate safely and efficiently.

2. Gas regulators can freeze over, causing gas pressure to drop below the required level.

    What you may notice:

1. The unit works fine sometimes but not as more equipment is running

2. Systems randomly lockout on flame failure

3. Excessive soot on cooking ware

4. Unit not lighting or pilot going out without cause

5. Noticeable difference in color of flames from equipment (typical flame on equipment is blue)

6. Uneven flame pattern

Heat pumps and water-source units - common problems during extreme cold:

1. Most heat pumps are not rated to run efficiently with the current temperatures, so they are designed with a backup/auxiliary electrical heat system (the backup system can fail separately and the unit can still operate)

2. Temperatures and windchills may freeze cooling towers, loops, and other exposed building piping that are not properly winterized or protected

       What you may notice:

1. Excessive running of HVAC unit and it can’t catch up to within 2-3 degrees of the thermostat

2. There is no noticeable difference when the units are running while the thermostat displays that it’s on backup heat, called Aux heat, W2 or emergency heat

3. Unit shutting off on low pressure or no flow

4. The system keeps locking out and will not reset

5. Unit is running but not satisfying the thermostat

If your system is operational, but struggling in extremely cold temperatures, you may have found a silver lining in a winter storm. The “stress test” that extreme cold creates shows equipment inefficiencies and potential failures that get hidden in easy operating conditions. This is true of HVAC & gas systems, but also Refrigeration equipment. It may seem counterintuitive, but extreme cold makes it harder, not easier, for refrigeration equipment to operate. 

If you notice any of the classic symptoms of system issues listed above, we strongly recommend that you schedule a service call before a breakdown.  Call or email us if you’re unsure; we’re happy to talk you through any equipment concerns to determine if they warrant a service visit.