The FT Series Floor Standing, Heating Only Boiler
Page 49
INPUT120 VOLT CIRCULATORS
XX
END
SWITCH
ZC ZR
120V RELAY
FUSE 1 AMP
SLAVE
MASTER
1234
ZONE 4
PRIORITY
ON
OFF
POWER
ZONE 2
ZONE 3
FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
PLUG-IN CARDS
RESET NORMAL
SR 504-EXP
120 VAC INPUT
T'STATS
LNG NGLNG
ZONE 1
L/ZC
Line Voltage Terminals
SYSTEM PUMP
T/T
MAIN POWER
AC24V
OUTPUT
Low Voltage Terminals Low Voltage Terminals
O/S
R 0-10V W
(+)INPUT (-)
(14 Gauge Wire)
LWC
O
I
OUTDOOR
SENSOR
LESS THAN
120 VAC
12 AMPS
TRANSFORMER
POWER TO 24V
(14 Gauge Wire)
*
DRY CONTACTS ONLY
DHW PUMP
L-T/T
TEMP
DHW
SENSOR
(Factory Jumper
Installed)
Low Water
Cutoff
SENSOR or
DHW TEMP
AQUASTAT
(18 Gauge Wire) (18 Gauge Wire)
ZONE 3 ZONE 2 ZONE 1
POWER
Wiring with multiple pumps and indirect DHW tank pump.
1. The traditional Taco SR-504 zone switching relay panel was used for illustrative purposes; other, similar
zone relay panels may be used. The relay panel does not require hot water priority because it is provided by
the FTHF boiler control. Modern zone switching relay panels with 2 end switches can be wired directly to the
T-T and DHW terminals without a ZC connection. End switches must be dry contacts only. Refer to item 7
below for proper set-up of parameter P39.
2. Connect the end switch from the relay panel back to the T/T terminals on the FTHF boiler.
3. Do not bring 24 V back to the T/T terminals. Only a dry contact switch is permitted.
4. Connect the ZC terminal from the relay panel back to the L/ZC terminal on the FTHF boiler.
Make sure to remove the factory jumper from ZC to ZR on relay panel.
5. Connect all heating zone circulators to the relay panel as indicated.
6. Connect the outdoor sensor (OS) to the OS terminals on the boiler.
7. The tank aquastat or DHW sensor connects back to the DHW sensor terminals. Use
parameter 39 in Section 5.7 to dene aquastat or DHW sensor setting to the boiler.
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