Dhw Method 3: Dhw Heating Using A Header Sensor Input - HydroTherm HeatNet KN -6 User Information

OPTIONAL FEATURES
begins, what to do with the local pump/valve is
determined:
NO The local pump/valve will remain running during
DHW heating.
YES The local pump will shut off with a delay
determined by LOCAL DELAY: seconds. This
allows the DHW pump/valve to prove before
shutting off the local pump.
Piping of the system will determine which setting to
use.
13. Press the DOWN arrow, the menu item: PURGE TO
THE: is displayed. After a DHW cycle completes, the
pump/valve can be selected to either purge to the
TANK, or to the SPACE for the duration of the post
purge time. This selection can use the space to dump
the heat from the boiler and not overheat the DHW
tank/load.
14. Set the HYB SENSOR = OFF. This sensor is
selectable for Method 5A only.
15. Finally, Press the UP arrow until the menu: DHW
BOILER? is displayed.. If JPS1 has not been cut, a
message will appear instructing to do so. Once this is
done, the MASTER boiler will control the temperature
in the tank using as many boilers as it has available on
H-Net along with the space heating needs. The boilers
must be piped appropriately for this method to function
correctly.
Now set up the Member boiler(s).
DHW BOILER? Set to MIXED on MEMBER boilers,
only the MASTER boiler.
DHW SETPOINT This does not need to be set on
MEMBER boilers, only the MASTER boiler.
LOWER DHW DIFF This does not need to be on
MEMBER boilers, only the MASTER boiler.
UPPER DHW DIFF This does not need to be set on
MEMBER boilers, only the MASTER boiler.
DHW PRIORITY This does not need to be set on
MEMBER boilers, only the MASTER boiler.
POST PURGE This needs to be set on all boilers. All
boilers control their respective DHW pump/valve
when they are called to perform DHW heating.
SHARING This can be set on any boiler and will how
boilers will cycle on/off when they are called to
perform DHW Heating.
LOCAL PUMP OFF This can be set on any boiler to
determine how the local pump/valve behaves
when called to perform DHW heating.
PURGE TO THE: This does not need to be set on
MEMBER boilers, only the MASTER boiler.
HYB SENSOR: = OFF. This sensor is selectable
for Method 5A only.
NOTE:
JPS1 MUST be cut on all boilers
providing DHW. Cutting JPS1 limits to maximum
temperatures to 200F.
DHW METHOD 3: DHW Heating using
a Header Sensor Input
This method will control a tank temperature when the tank
temperature setpoint needs to be maintained for extended
periods with minimal cycling. Multiple boilers can be used
via the H-Net, as this method employs the same PID
algorithm as for space heating. ADVANCED SETUP:
DISTRIBUTED CTRL: MASTER TYPE: AUTO.
1. JPS1 must be cut on all boilers providing DHW
to ensure the maximum output temperature of all
boilers is limited to 200F for DHW operation.
This Method is very similar to the DHW only
method, but:
A. The display will not indicate that it is a
DHW heating boiler.
B. The DHW Heating band will also not be
displayed.
C. The heating band will use the space
heating band and not the UPPER and
LOWER DHW heating band limits.
D. DHW settings are not used.
E. Set the ADVANCED SETUP:
DISTRIBUTED CTRL: MASTER
TYPE: to AUTO.
F. This method is for backwards
compatibility.
2. Use the Heat Demand Control Method 1
located in the CONTROL METHODS section on
page 22. Instead of placing the Header sensor in
the Header pipe, place it in a well, in the tank, or
a DHW loop.
The temperature at which boilers are staged ON,
and then OFF is controlled by the
SETUP:BOILERS:HEAT BAND differential.
This can be understood by referring to the
INTRODUCTION section on the MASTER in
the beginning of this manual.
This differential has the added effect of heating
the tank above the tank's setpoint temperature. If
HeatNet Control V3 2.x
Page 43