WARNING SYMBOL: THIS SYMBOL INDICATES THE PRESENCE OF HAZARDS WHICH
CAN CAUSE SEVERE PERSONAL INJURY, SUBSTANTIAL PROPERTY DAMAGE OR
EVEN DEATH IF IGNORED.
D 704
04/05
General
The Mixing Station 704 represents a breakthrough in the design, control and installation of radiant systems. The patent pending design
combines a variable speed injection mixing control (RMC), injection circulator, system circulator, and air elimination into a single unit.
Extremely versatile, the Mixing Station 704 can be set up to operate as an outdoor reset control, a setpoint control or a delta T limiting
control.
Mixing Station 704
RADIANT MIXING CONTROL (RMC)
MIXING STATION 704 (RMB)
Table of Contents
TYPICAL PIPING ------------------------------------------------- 2
GETTING READY ------------------------------------------------ 3
APPLICATION ---------------------------------------------------- 3
DESIGN PROCEDURE -----------------------------------------3
INSTALLATION OF MIXING STATION 704 --------------- 4
OUTDOOR RESET MODE ------------------------------------ 5
OUTDOOR RESET SETTINGS ------------------------------ 5
SETPOINT AND DELTA T MODE --------------------------- 6
SETPOINT AND DELTA T SETTINGS --------------------- 7
BOILER OPERATION MODE ---------------------------------7
Check the contents of this package. If any of the contents listed are missing or damaged, please contact your wholesaler or tekmar
sales representative for assistance.
Contents should include the following:
• One Mixing Station 704, unit consisting of the following parts: (One Radiant Mixing Control, One Blue Enclosure, One
Casing with two circulators attached, One Backplate, One Power Cord (6 feet, attached to backplate))
• One 070 Outdoor Sensor
• One Universal Sensor 071
• One Universal Sensor 082
• Data Brochure D 704
Application
The Mixing Station 704 is a complete injection mixing system. Integral to the unit is a variable speed injection circulator, constant
speed system circulator, air elimination, and the electronics to drive it all. With only four piping connections needed, the RMB greatly
reduces the time and space required for installation. The RMB can be set up to operate as an outdoor reset control, a setpoint control
or a delta T limiting control, creating fl exibility never seen before in a single unit.
Design Procedure
1. Using the pump curve located below, ensure that the System Pump of the Mixing Station 704 will provide adequate fl ow for the
system in which it is to be installed.
2. Using the table or equation below, determine the required fl ow rate for the Injection Pump.
3. Using the pump curve located below, ensure that the Injection Pump of the Mixing Station 704 will provide adequate fl ow for the
system in which it is to be installed.
SYSTEM PUMP CURVE
5.5
4.8
4.2
3.6
3.0
2.4
HEAD (m)
1.8
1.2
0.6
18
16
14
12
10
8
HEAD (ft)
6
4
2
0
0
051015
01.142.273.41
FLOW (gpm)
3
FLOW (m
/h)
REQUIRED INJECTION PUMP FLOW RATE
Tb = Boiler Supply Temperature
Ts = Radiant Supply Temperature
1. Mounting position – The Mixing Station 704 must be mounted in the vertical position with the automatic air vent located at the top
of the Mixing Station 704.
2. To mount the Mixing Station 704 begin by removing the Radiant Mixing Control from the front of the Mixing Station 704. Remove
the screw and pull the Radiant Mixing Control straight forward. Ensure that the Radiant Mixing Control is stored in a safe place until
it is ready to be remounted.
3. Remove the three screws holding the blue plastic cover to the Mixing Station 704.
4. Select a suitable location to mount the Mixing Station 704 that allows suffi cient space for easy pipe connections.
5. Attach the sheet metal base to the wall with screws (not included) through the small mounting holes. See technical data for hole
location and spacing.
6. Using four suitable screws (not included), fasten the Mixing Station 704 to the selected location. Ensure that at least two of the
mounting screws are attached to a wall stud or similar surface.
STEP TWO PIPING CONNECTIONS
1. Using proper piping practices, connect the supply to the radiant heating system to the Radiant Supply (bottom right hand connection) as indicated on the plastic cover of the Mixing Station 704. Ensure that a proper isolation valve is installed.
2. Using proper piping practices, connect the return from the radiant heating system to the Radiant Return (top right hand connection)
as indicated on the plastic cover of the Mixing Station 704. Ensure that a proper isolation valve is installed.
3. Using proper piping practices, connect the supply from the boiler loop to the Boiler Supply (top left hand connection) as indicated
on the plastic cover of the Mixing Station 704. Ensure that a proper isolation valve is installed.
4. Using proper piping practices, connect the return to the boiler loop to the Boiler Return (bottom left hand connection) as indicated
on the plastic cover of the Mixing Station 704. Ensure that a proper isolation valve is installed.
5. Connect the Boiler Supply and Boiler Return lines to the boiler loop using standard Primary Secondary piping practices.
STEP THREE FILLING
1. Fill system with tap water – The system must be fi lled before operating the circulator. The bearings are water lubricated and should
not be allowed to operate dry. Filling the system will result in immediate lubrication of the bearings. It is always good practice to fl ush
a new system of foreign matter before starting the circulator.
2. Circulator operation – Operate the circulators for 5 minutes immediately after fi lling system to purge remaining air from the bearing
chamber. This is especially important when installing the circulator during the off-season.
STEP FOUR REPLACING THE FRONT COVER
1. Place the blue plastic cover over the Mixing Station 704.
2. Using the original three screws, fasten the blue plastic cover to the Mixing Station 704.
3. Reinstall the Radiant Mixing Control and fasten it in place with the remaining original screw. RMC wiring starts on page 9.
STEP FIVE ELECTRICAL CONNECTIONS
1. Electrical connections – Observe all applicable codes when connecting to power supply. The motors are impedance protected, and
do not require overload protection. The pumps cannot run backwards.
WARNING:
Do not use in swimming pool or spa areas; pump has not been investigated for this application.
WARNING:
In the event the retaining screws have been pulled out of the housing, DO NOT replace them. Use of any other screw
may short out the stator windings, creating a risk of electrical shock.
CAUTION:
1. The addition of petroleum based fl uids or certain chemical additives to systems utilizing TACO equipment voids the
warranty.
2. Use supply wires suitable for 194°F (90°C) – ATTENTION: Employer des fi ls d´alimentation adequats pour 194°F (90°C).
WARNING:
To avoid electrical shock, disconnect the power supply to the circulator and the main electrical unit.
In order to properly control a hot water heating system, the amount of heat
supplied to the building must equal the amount of heat lost by the building.
The amount of heat delivered into a building depends on the temperature of
the water in the heating unit and the surface area of the heating unit. Heating units with a small surface area, such as baseboard radiators, require a
higher water temperature than heating units with a larger surface area such
as radiant fl oors.
The amount of heat lost from a building depends on the outdoor temperature.
As the outdoor temperature becomes colder, the amount of heat a building
loses increases.
The operation of a hot water heating system can generally be improved by
adjusting the supply water temperature to the system as the outdoor temperature changes. Using this approach, the heat input to the building can
be matched to the heat lost from the building. This method of controlling the
supply water temperature to a heating system greatly improves the comfort
of the system and is known as Outdoor Reset.
When an Outdoor Sensor is connected to the Radiant Mixing Control (RMC), the RMC provides outdoor reset. When operating in the outdoor
reset mode of operation, the installer must set the Outdoor Design Temperature and the Design Supply Temperature in order to establish
the relationship between the outdoor temperature and the supply water temperature. This is known as setting the Heating Curve.
SEQUENCE OF OPERATION
When the RMC receives a Demand and it is not in a WWSD, the RMC turns on the system pump and calculates a Mixing Target temperature. The variable speed injection pump is then operated to maintain the Mixing Target temperature at the mixing supply sensor.
The boiler contact operates as described in the Boiler Operation section. The RMC also provides boiler protection as described in
the Boiler Operation section.
DEMAND
The RMC requires a demand signal before it will begin operation. The RMC can use either a powered or an unpowered demand
signal. Once a demand signal is received, the RMC displays the demand pointer in the
display and operates as described above.
Powered Demand
The RMC recognizes a Powered Demand Signal when 24 V (ac) is applied across the
Com and Heat Dem terminals.
Unpowered Demand
The RMC recognizes an Unpowered Demand signal when a switch is closed between
the Com and Heat Dem terminals.
SYSTEM PUMP OPERATION
The RMC has an internal system pump contact. This contact turns on when the RMC has a
mixing demand and is not in a WWSD. The integrated system pump as well as an external
boiler pump may be controlled by this relay. By providing proper fl ow in the boiler loop, the
boiler temperature can be accurately controlled based on the mixing load.
Powered
Demand
C
24 V (ac)
R
Unpowered
Demand
Boil Out
Switch
Boil Out
Switch
Com Heat
Dem
Com Heat
Dem
Outdoor Reset Settings
HEATING CURVE SETTINGS
In order to establish the heating curve, the RMC must be given two points to work with. The fi rst point is the Outdoor Reset Starting
Point and the second point is the Design Condition.
Outdoor Reset Starting Point
The Outdoor Reset Starting Point for the RMC is fi xed at 72°F (22°C). This means that when the outdoor temperature is 72°F
(22°C), the RMC calculates a required supply water temperature (Mix Target) of 72°F (22°C).
Design Conditions
The design conditions represent the supply water temperature required to satisfy the heating system on the typical coldest day of
the year. These are the conditions that are used when calculating the size of the heating equipment needed to heat the building. The
Design Conditions are made up of an outdoor temperature (Outdoor Design) and a supply water temperature (Design Supply).