HELIX VX-399 Installation, Operation & Maintanance Manual page 32

NOTICE
IMPORTANT: Do not apply power to DHW T-T
terminals. Dry contact only, use of isolation relay
may be necessary.
B. Maximum wire length is 330 ft (100m) 22 gauge wire.
C. Connect wires (interchangeable) to DHW T-T
terminals. Wires are interchangeable.
• Central Heating Thermostat
A. Use thermostat or boiler system control with dry
contacts related 0.5 amps @ 120 VAC. Boiler control
does not provide 24 VAC power to central heating
thermostat.
B. Locate and install thermostat per manufacturer's
instructions. Maximum wire length is 330 ft (100m) for
22 ga. wire.
C. Connect wires to CH T-T terminals. Wires are
interchangeable.
• Low Water Cutoff (LWCO)
Factory installed.
NOTICE
Boiler transformer does not have adequate VA to
power accessories, other than factory supplied
LWCO.
8-4
FIGURE External Connections (Do not apply external voltage to external terminals.)
8 - ELECTRICAL CONNECTIONS
Use dry contact for wires to CH T-T terminal and
DHW T-T terminal. E33 error code is displayed if
voltage is sent back to the control board. If error
is not corrected for extended period of time, this
voltage can permanently damage control board.
FIGURE
and DHW Pump
32
NOTICE
8-3
Isolation Relays for CH System Pump
GENERAL
P/N 240010943, Rev. C [09/07/2016]
Note: Supplied
with Factory
Installed Jumper