CTRLMax Manual

56
CHAPTER 8
CHAPTER 8 - CASCADE
8.3. CTRLMax Cascade menu structure
8.4. Cascade Installation
8.4.1 System Piping
Standard Cascade installations will utilize a balanced
manifold system as the primary / secondary connec-
tion to the system piping as shown in Fig. 27 on page
67 or a reverse return piping arrangement as shown
in Fig. 29 on page 69.
Split Cascade installations will utilize a balanced man-
ifold system as the primary / secondary connection
to the central heating loop. Each boiler congured to
respond to a domestic hot water call will also have a
direct connection to the indirect water heater as shown
in Fig. 31 on page 71. Reference the boiler Installa-
tion and Maintenance Manual for general boiler instal-
lation and piping requirements.
8.4.2 System Sensor Installation
Cascade operation requires a System Temperature
Sensor to be installed on the common supply header
downstream of all boilers in the system.
Place the System Temperature Sensor within 10’ of the
last boiler in the Cascade System for an accurate tem-
perature reading. Proper placement and installation of
the System Temperature Sensor is critical for reliable
cascade operation. The type of System Temperature
Sensor chosen also greatly aects the accuracy of the
system temperature readings.
Three types of System Temperature Sensor are available:
• Direct Immersion - A direct immersion tem-
perature sensor (MDRKIT05) is the recommend-
ed type since it will provide the most accurate
water temperature readings. Install the 1/2” NPT
direct immersion temperature sensor in a tee
on the common supply header downstream of
all boilers in the system. Ensure that the tem-
perature sensor probe is directly in the water
ow but not touching the opposite side of the
tee. Wire the sensor to terminals 3 & 4 of X5 on
the control module of the Master boiler.
• Dry Well Installation – A temperature sensor
(PSRKIT22) installed in a dry well will measure
up to 10°F [5°C] lower than the actual water
temperature. All water setpoints must be low-
ered at the Master boiler by 10°F [5°C] from
the desired setpoints for reliable Cascade op-
eration. Install a 3/8”ID drywell in the common
supply header downstream of all boilers in the
system. The drywell should be long enough to
be directly in the water ow for the most accu-
rate temperature reading. Insert the tempera-
ture sensor into the well and wire to terminals 3
& 4 of X5 on the control module of the Master
boiler.
• Pipe Mounted Installation – A temperature
sensor (PTSENS12) mounted to the outside of
the pipe will measure up to 20°F [11°C] lower
than the actual water temperature. All water
setpoints must be lowered at the Master boil-
er by 20°F [11°C] from the desired setpoints for
reliable Cascade operation. The Pipe Mounted
temperature sensor can be directly strapped to
the outside of a 1” to 3” metallic pipe.
Cascade
Cascade Info.
?
Cascade
Information
Cascade
Settings
Cascade
Autodetection
CTRLMax_w Instinct_UK version_222171_A01.indd 56 18/07/2019 18:38