Heat Controller Water Source Heat Pump AcceptableRange, Checking Comm. Loop Voltages, Section

WattMaster WHP Section 4

5.3 Checking Comm. Loop Voltages

5.3.1Checking the CommLink II Network Loop

Diagram

Overview

This test checks for proper Network loop voltages at the CommLink II.

The Loop LED (located on the front panel) should “flicker” when the CommLink II is

Tip:attempting to communicate. The Loop LED will flicker more noticeably for a few seconds when first powered up. If the Loop LED does not flicker, the unit is defective. Make sure CommLink II jumper is set to “Multi” position.

Proper loop voltages are essential for reliable communications. It is normal to see fluctua- tions at this point on the CommLink II. The average value should be close to the acceptable range described below. Values will vary upon initial powerup for about 10-15 seconds as the unit attempts to communicate.

Measurements

TNetwork- G (SHLD)Loop	2.9 - 3.1 Volts DC	AcceptableRange
R - G (SHLD)	1.9 - 2.1 Volts DC

Action

If voltages are tooConditionhigh or too low on either side

1.Unplug the NetworkActionloop from the CommLink II and check for proper loop

voltages. If problem exists, disconnect each MiniLink Network loop until the problem is isolated.

2.Check the CommLink II Driver chip. Replace the driver chip if necessary

4-24 Start-Up and Troubleshooting