Tekmar Universal Reset Control 363 Data Brochure Download Page 15

Page: 15 / 40

15 of 40

ROOM TEMPERATURE UNIT (RTU) 062, 063

If the mixing system consists of a single zone, temperature control of that zone can be provided
by using an RTU. The RTU is connected to the

Com and tekmar Net

tN1/tN2 terminals (17

and 19). In addition, power must be applied to the

Mix Demand terminals (1 and 2) as

described in Section D1. With the RTU connected, the 363 measures the actual room
temperature. With this information, the 363 provides a constant water flow through the mixing
system. At the same time, indoor temperature feedback fine tunes the supply water
temperature in the mixing system to prevent over heating or under heating. The RTU allows
the user to adjust the desired room temperature at the RTU. Remote sensor capability is also
available through an RTU as described in the RTU data brochure.

Section E1 —General Storage Operation

MIXING STORAGE (

MIXING

STOR

)

By using the 363, it is possible to incorporate a thermal storage tank into the
mixed side of the heating system. This storage tank could be charged with
heat using an alternate heat source such as solar, wood, or off peak electrical.

Set the

MIXING

item to

STOR

. When using the

STOR

selection, it is not

possible to use a floating action actuator as the mixing device; Variable
speed injection pumps must be used. A variable speed injection pump is
used to draw heat from the storage tank and inject it into the mixed system
loop. Pipe the storage tank and boiler loop variable speed driven mixing
pump as illustrated. Whenever possible, the 363 uses the heat in the
storage tank to satisfy the mixing system. However, if the storage tank is
not able to satisfy the mixing system, the 363 uses the variable speed
injection pump connected to the boiler loop. This pump provides heat to the
mixing system from the boiler.

Note: A relay must be installed as described in the wiring section for the 363
to switch the variable speed output signal between the storage tank
injection pump and the boiler loop injection pump.

Section E2 —With a Tank Sensor

10K 2 STORAGE (

10K 2

STOR

)

For the best operation of a system that has a thermal storage tank, it is
recommended to use a tekmar 10K sensor in the storage tank. The sensor
measures the tank temperature and connects to the 363 on the

Com and

10K 2 terminals (17 and 18). Set the

10K 2

setting to the

STOR

item. With

the sensor installed, the 363 learns the required temperature difference
between the current tank temperature and the mixing target temperature
that still allows heat transfer.

If the tank temperature is sufficient to satisfy the system, the 363 operates
the storage tank’s variable speed pump. If the tank temperature is not
sufficient, the 363 switches to the boiler variable speed pump. Whenever
the 363 is using the boiler variable speed pump, the 363 continues to
monitor the tank temperature. If the tank temperature increases enough to
satisfy the mixing requirements, the 363 switches back to the storage tank’s
variable speed pump for as long as possible.

Use of the tank sensor allows the control to display the current storage tank
temperature in the

View menu and record the highest and lowest

tank temperatures.

Sequence, Section E

Secondary

Heat Source

Var

Tank Sensor

Mix Sensor

Boiler Sensor

Var

Secondary
Heat Source