Category: Consideration

Bubble Solution Leak Detection Method

A common method of leak detection is the use o f a leak detecting solution such as a water/soap solution (Figure SP-1-2). Its main advantages are low cost and ease of use. The solution is brushed over the area suspected of leaking. G as coming through the solution will cause bubbles to form. If the […]

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Multimeters – Measuring Current

Making current measurements with a multimeter is different than making other measurements with a multimeter. Current measurements are made in series, unlike voltage or resistance measurements, which are made in parallel. The entire current being measured flows through the meter. As previously discussed, the clamp-on ammeter is used to make most of the higher A […]

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Multimeters (VOM/DMM) Basics

Analog (VOM) and digital (DMM) multimeters are used to measure voltage (volts), resistance (ohms), and current (amperes). Some can be used to make other measurements such as temperature or high current; these usually involve the use of one or more special probes or accessories that are readily available. Figure 3-23 shows an analog multimeter. The […]

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Multimeters – Measuring Voltage

Voltage measurements are usually made to determine source voltage, voltage drop, and/or voltage imbalance. Be sure to always connect the multimeter across (in parallel with) the circuit being measured. Know the capabilities and limitations of your multimeter before attempting any measurements. Read and follow the manufacturer’s instructions. See Figure 3-24. Make voltage measurements as follows: […]

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Multimeters – Measuring Resistance

Multimeters can measure the resistance in ohms (£2) of all or any part of the circuit. Resistance values o f HVAC components can vary greatly from a few ohms to several million ohms. Most multimeters can measure below one ohm; some measure as high as 300 million (meg) ohms. Multimeters contain their own battery power […]

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Ammeters Basics

Ammeters measure current flow through a circuit. Depending on the level of the current being measured, the ammeter reads in amperes, milliamperes (one thousandth of an ampere) or microamperes (one millionth of an ampere). Current must flow directly through the ammeter meter movement for it to record. For this reason, standard (in-line) ammeters such as […]

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Disconnecting the Gauge Manifold

The procedure used for disconnecting the gauge manifold set varies, depending on the type of service valves installed in the unit. If the unit being serviced contains back-seating service valves, the charge remaining in the hoses can be drawn back into the operating system using the following procedure: 1. On the gauge manifold set, close […]

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Connecting the Gauge Manifold

For years, refrigerant has been used to purge air from the service hoses prior to making the final connection to the unit. Obviously this causes refrigerant to be released to the atmosphere. To comply with the no-venting requirements, certain precautions must be followed when connecting or disconnecting the gauge manifold set. When connecting the gauge […]

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Adjusting the Gauge Manifold

Figure 3-15 shows how the flow of refrigerant through the gauge manifold set is controlled. The hand valve on the left controls the flow to or from the low side of the system. The one on the right controls the flow to or from the high side of the system. When either valve is turned […]

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