Application Guide

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© 2016 tekmar 670
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Multiple Zones with Multiple Boilers and Shared Mixing Valve A670-8 Mechanical
400
V1
B1
423 & 346
444
B2
M1
S4
S5
S6
tN4 Mix 1 Bus
Description
The system has two snow melting zones heated by two boilers. The water temperature is regulated by a shared mixing valve
for the two snow melting zones. The boilers and mixing valve are operated by a Universal Reset Module 423, Power Manager
346 and Mixing Expansion Module 444. Each snow melting zone is operated by a WiFi Snow Melting Control 670.
• The slab target is determined by the melting/idling/storm setpoint and by the measured outdoor air temperature.
• The zone pump cycles on/off when heating the slab during melting/idling/storm operation.
• When the zone is heated, the 670 communicates to the 423 and 444 to operate the mixing valve and fire the boilers.
•
The 423 and 444 close the mixing valve to provide boiler return protection when the boiler supply temperature falls below
the 423 boiler minimum setting.
The system operation is dependent on sensor selection, as listed in the table below.
Sensor options Operation methods
Sensor Sensor Model(s)
Auto Start/
Auto Stop
Auto Start/
Timed Stop
Manual Start/
Timed Stop
Slab Temperature
Control
S1 Automatic Snow/Ice Sensor 090 or 094 • – • •
S2 Aerial Snow Sensor 095 – • • –
S3 Slab Sensor 072 or 073 – – • •
S2+S3 Aerial Snow Sensor 095 and Slab Sensor 072/073 – • • •