This Week's Category:
AIR & NATURAL GAS

Monday - Air consist of 20.9% Oxygen, 78% Nitrogen and the remainder about 1% inert gases.

Tuesday - Natural Gas is generally considered 1050BTU’s per cubic foot (it may range between 900-1200BTU’s).

Wednesday - Natural Gas requires 10-12 cubic feet of air for proper combustion or 2 cubic feet of Oxygen.

Thursday - Natural gas is lighter that air and tends to dissipate.

Friday - Natural gas is supplied near 8” of WC, to a standard home appliance. It should not drop once the appliance has begun operation more than .5”WC.

This Week's Category: BTU's

Monday - A BTU is an abbreviation for British Thermal Unit, the amount of energy required to raise 1 pound of water 1 degree F.

Tuesday - A BTU is a relatively small amount of energy, about equivalent to the heat generated by striking 1 match stick.

Wednesday - One Ton of cooling is 12,000 BTU’s

Thursday - A Therm is 100,000 BTU’s

Friday - Natural gas is lighter that air. LP gas is heaver than air and will pool in low spots. Use both gases in well ventilated areas.

This Week's Category:
Rooftop Units Continued

Monday - In general, a High Pressure Event is reached at less 400PSIG for R22 and less 600PSI for R410A.

Tuesday - In general, a Low pressure events are less 30 PSIG for R22 and less 50 for R410A.

Wednesday - A freeze protection event occurs because at the sensor it has reached a temperature less 30°F, it must warm above 44°F to reset.

Thursday - A roof top unit has 2 primary methods of metering refrigerant: TXV & fixed orifice. Today this fixed orifice is called an Accutrol.

Friday - To see if an Accutrol if feeding properly, remove the belt and look for an even frost pattern between all of the evap inlets (less than 2 minutes).

This Week's Category:
Rooftop Units

Monday - Checking a charge on a roof top unit must be done with all the panels in place. Look for a knockout to pass your hoses through.

Tuesday - If you are cleaning a condenser coil, check if it’s a double row coil. If it is you must split the coils for proper cleaning.

Wednesday - Before opening power to unit, if no A/C, check “X” terminal on low voltage terminal board. Is there power present with respect to “C”?

Thursday - If there is Power present; your CLO (Compressor Lock Out) device has been engaged. Look at you diagram to see what would cause this.

Friday - If the CLO has a compressor stage “Locked Out” the economizer will still function if the outdoor air is sufficient for cooling.