Crown Aruba 5 Installation Manual

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2. Low Voltage Connections – Low voltage eld connections are located as shown in Figure 9.1 and are as follows:
a) Heating Thermostat - Connect to a 24 volt thermostat or other “dry contacts” (such as a zone panel end switch) that
close upon a call for heat. Follow thermostat manufacturer’s instructions. To insure proper thermostat operation, avoid
installation in areas of poor air circulation, hot spots (near any heat source or in direct sunlight), cold spots (outside
walls, walls adjacent to unheated areas, locations subject to drafts). Provide Class II circuit between thermostat (or zone
controls) and boiler.
b) DHW - If used, connect to a 24VAC domestic hot water thermostat or 2nd space heating thermostat.
c) Option Plug - Used to connect options such as the Crown Option Card Panel kit (See instructions provided with this kit
for additional details).
Note: When the Option Plug is not used, the factory supplied jumper plug shown in Figure 9.1 must be installed for
boiler to operate.
d) EnviraCOM - Used to connect EnviraCom thermostat or other EnviraCom device approved by Crown for use with this
boiler.
CAUTION
• When making low voltage connections, make sure that no external power source is present in the thermostat
circuits. If such a power source is present, it could destroy the boiler’s control. One example of an external power
source that could be inadvertently connected to the low voltage connections is a transformer in old thermostat
wiring.
• Do not attempt to use EnviraCOM connections for any purpose not explicitly permitted by Crown Boiler
Company. Attempting to do so may result in unreliable operation and/or damage to controls.
• Do not use the transformer provided on the boiler to power external devices such as zone valves. Doing so may
cause damage to the transformer.