45
To determine if a zone is calling:
On Damper Relay board, measure voltage from W to W and Y to Y
(TB1 to TB2). If the voltage is at least 8 volts for System 1000 or 20
volts for System 2000, that zone is calling. If voltage is between W
and W, zone is calling for heat. If between Y and Y, zone is calling
for cool. To take this reading, RD must also be powered which
means the Switching Center/Controller has recognized the call
(Damper light on). Note: Do not test for a call by measuring the
voltage from Y to C or W to C on TB2. The system utilizes pull up
resistors which can give you false readings.
If Controller/Switching Center transformer fuse is blowing:
1.
Check for short on five wire link between RD and B or between
G and B.
2.
Check for short on thermostats between R and C.
If Controller circuit board fuse is blowing (System 2000 only):
Make sure that the voltage between TR1 and TR2 is not less than 24
V or more than 30 V. If voltage is okay, replace Controller. If volt-
age is not within range, be sure you have the correct transformer and
that the primary voltage is adequate. If primary voltage is okay and
transformer is correct size, replace transformer.
If Controller off circuit board fuse is blowing (System 2000 only):
You have a short on the five wire link between either Y and G, W and
G, Y and Rd, or W and Rd.
If System 1000 SYHPA Switching Center circuit board fuse is
blowing:
You have a short on the five wire link between either YD and GD, WD
and GD, YD and RD or WD and RD.
SYSTEM 1000/2000 TERMINAL DESCRIPTIONS
Daisy Chain, 5 or 6 Wire Link:
1.
GD/G
Hot wire, 24V. Hot when Switching Center/Controller
TR1 is hot. For System 2000, turning Controller Power
switch off will remove power from GD. The Power switch
will not remove power from GD on System 1000.
2.
BD/B
24V return (chassis ground). Measure all Daisy Chain
voltages in reference to this terminal.
3.
RD
Hot when the Switching Center/Controller recognizes a
thermostat call. Damper light on Switching Center/ Con-
troller is on when RD is hot.
4.
YD/Y
Cool call, hot when cool call recognized by Switching
Center/Controller. For System 1000: 5V to 16V (1 to 7
zones calling). For System 2000: 212 mv to 3.64V
(1 to 20 zones calling). There should never be 24V on
this terminal when the System 1000 Switching Center
green light is on and the mode switch is at “Cool” or
when the System 2000 Controller’s “Damper” and
“Cool” lights are on. If there is, you have a short to either
RD or GD.
5.
WD/W Heat call, hot when heat call recognized by Switching
Center/Controller. Voltages the same as for YD. There
should never be 24V on this terminal when the System
1000 Switching Center green light is on and the mode
switch is at “Heat” or when the System 2000 Controller’s
“Damper” and “heat” lights ar on. If there is, you have
a short to either RD or GD.
6.
W2
Second stage heat call. 24V when second stage of zone
thermostat is calling. Only used with System 1000 SYHPA.
Damper Relay Board:
1. TB2:
a.
MC
Motor common. Return for 24V damper motor(s).
Motor voltages measured in reference to this termi-
nal.
b.
RC
Run Closed. 24V when damper motor closing.
c.
RO
Run Open. 24V when damper motor opening.
d.
R
24V hot. Same as GD.
e.
C
24V return. Same as BD.
f.
W
Thermostat heat call. See below how to determine
if a zone is calling.
g.
Y
Thermostat cool call. See below how to determine
if a zone is calling.
h.
W2
Second stage thermostat heat call. Same as W2 on
Daisy Chain.
2. TB1:
Daisy Chain. See Daisy Chain, 5 or 6 Wire Link above.
SYSTEM 1000/2000 TROUBLE SHOOTING
