Application Note

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Application Note

F r o m t h e F l u k e D i g i t a l L i b r a r y @ w w w . f l u k e . c o m / l i b r a r y

Troubleshooting

HVAC systems

with the Fluke 233 True-rms

Remote Display Multimeter

I heard audible gasps from the

assembled maintenance techs at

a large university in the south-

eastern United States when I

showed them how I used my

new Fluke 233 True-rms Remote

Display Multimeter.

Of all the great Fluke products

I have seen and used, this one

has the potential to revolution-

ize the troubleshooting of HVAC

systems.

The main section of the 233 meter stays in place while the techni-

cian uses the detachable display to check results elsewhere.

A technician can compare the results on the 233’s detachable display to

the reading on a remote thermostat.

The HVAC industry has a bad

habit of locating mechanical

devices where they are very

hard to gain access to, including

on rooftops, in crawl spaces and

above ceilings. These mechani-

cal units often have controls

located inside the building on

interior walls or inside control

panels. Speaking for myself, I

am not getting any younger, so

it is not as easy for me to climb

up and down ladders repeatedly

to check multiple readings in

different locations.

Using standard multimeters,

people like me must somehow

be in two places at the same

time in order to check the unit

operation in both places. The

Fluke 233 True-rms Remote

Display Multimeter has a detach-

able display that allows the

technician to locate the meter,

probes and accessories on the

electrical device being checked,

then detach the remote display

to permit viewing of the values

at another location, such as a

controller. When combined with

the features present in these

meters, quick troubleshooting of

HVAC system problems becomes

easier. Some common examples

are as follows:

1. Remote voltage measurement

and troubleshooting.

2. Remote continuity mea-

surement to check wiring

integrity.

3. Remote temperature readings

while at a thermostat.

4. Remote min/max voltage

quality troubleshooting.

5. Control system sensor reading

calibration.

Here are troubleshooting scenar-

ios for each of these examples:

1. Remote voltage measure-

ment and troubleshooting.

An HVAC technician receives

a too-hot complaint from a

residence. Upon arrival, he

determines the unit is not

running. The tech desires

to test the operation of the

contactor while adjusting the

thermostat into the cooling

mode. He turns off the unit at

the thermostat and connects

the meter probes at the load

side of the contactor. Then he

detaches the remote display

and takes it inside the home.

Summary of content (2 pages)

PAGE 1
Troubleshooting HVAC systems with the Fluke 233 True-rms Remote Display Multimeter I heard audible gasps from the assembled maintenance techs at a large university in the southeastern United States when I showed them how I used my new Fluke 233 True-rms Remote Display Multimeter. Of all the great Fluke products I have seen and used, this one has the potential to revolutionize the troubleshooting of HVAC systems.
PAGE 2
He places the system switch at the thermostat baseplate into the cooling mode. The voltage reading is zero, indicating that the contactor did not engage. He inserts the remote display into the meter and does further checks at the contactor, which he then determines has failed. The tech replaces the contactor and puts the system back into service. 2. Remote continuity measurement to check wiring integrity. A tech is called into a medical office building due to a too-cold complaint.