34000 Autry Street, Livonia, MI 48150 | 800.968.5530 | Fax 734.419.0209 | www.hamiltonengineering.com | LIT91127US REV 5/2018
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B. EVO CONTROLS CONT.
GENERAL INFORMATION
Central Heating -
The EVO controller has many built-in functions for precise control in Central Heating
applications. The controller can operate on its own internal Flow (outlet) sensor, however the preferred
method is to use an External Sensor connected to the Lead Boiler. If the External Sensor is not
employed, the boiler(s) will need to have a constant flow of water so that the internal sensors can accurately
detect the loop temperature.
When the External sensor is installed in the main building loop or a Hamilton System Separator (low loss header),
the boiler system operates at peak efficiency, reducing short-cycling and maintaining a constant loop temperature.
The External Sensor must be installed in a location that has good water flow - avoid positions where the sensor
will be located in stagnant flow areas or in the near boiler piping.
See LIT91110 - FMT-914 Control Configurations
for suggested locations.
In a Central Heating application, the EVO controller can utilize an outdoor thermistor for outdoor reset (without
the need for an external controller), remote setpoint control from a BMS or external controller (0 - 10 VDC), and
indirect DHW priority. See below for additional details on these features.
Outdoor Reset -
The EVO controller will automatically operate while in the Central Heating mode, utilizing
Outdoor Reset. When a 10K ohm thermistor is connected to the EVO, the controller will automatically
change the temperature setpoint to a calculated value based on the programmed outdoor reset curve.
The setpoint selected by the outdoor reset curve can be shifted (parallel shift) up to 36°F above or below
by adjusting the temperature control knob on the display.
BMS 0 - 10VDC control -
The range of 0 – 10 volts corresponds directly to the temperature range imbedded
in the control software. Factory default for heating boilers is 50°F – 194°F. With the standard parameter
sets, the following would be true:
0 - 0.9 volts = boiler(s) off
1
volt
=
50°F
4
volts
=
98°F
7
volts
=
146°F
10
volts
=
194°F
(each
volt
=
16°F)
Voltage can be sent in any value between 1 and 10 and the temperature set point will be the exact value that
corresponds to that voltage. Below 1 volt, there will be considered no heat demand.
Note: If another type of heat demand device is connected to the EVO, such as a room thermostat (or the
jumper wire factory shipped in place), the controller will revert to that as it’s control point when the voltage is
less than 1. If the 0–10 VDC signal is lost from the external source, such as a BMS, the control will revert to
its maximum set point if there is a jumper or other closed thermostat connected to the “Room Thermo-
stat” terminals. If this is not desired and heat with some form of control is desired, a relay may be used.
The relay coil can be energized from the control source (i.e. BMS) and the common and NC contacts
from the relay can be connected to the room thermostat terminals and an outdoor air sensor connected
to the appropriate point on the EVO terminal strip. If power is ever lost from the control source, the relay
will de-energize and close the room thermostat terminals, thus activating the outdoor reset (see above
for control).