Figure 8.2.6.1 Load Control Graph; Figure 8.2.6.2 Temperatue Control Graph - Hamworthy MILBORNE381 Series Design Installation, Commissioning And Operating Instructions

Should the high temperature heating circuit be
operating at a lower temperature whilst there is a dhw
demand, the high temperature pump (P1) will be
disabled to prevent overheating in the heating zone.
8.2.5 Temperature Control
Whilst the maximum and minimum settings for the
heating circuits are set during commissioning, the User
can adjust the operating set-points within these limits
via the Master control.
8.2.6 Building Management System Control
Where required, the Master control can be set to
accept a 0-10v analog control signal. This can be
configured for temperature or load control and will
control the modulation of the boiler(s).
All safety interlocks MUST be wired across the 0-10v
circuit using suitable low voltage contact ratings.
A 0-10v input signal, can be used to control one
temperature circuit only. Either a High or Low
Temperature circuit, or Primary circuit, can be
controlled under the direction of the BMS signal.
Any additional secondary circuits
controlled by the BMS.
When using the Master control to manage temperature
requirements, a separate time clock for each circuit is
required. All external clocks must have volt free
switching contacts.
When multiple Master boilers are used in the same
heating system it is important to ensure a BMS is used
to enable each Master Control using 0-10Volt analog
signal. Each Master Control requires it's primary flow
temperature sensor locating in a pocket installed in the
flow pipework between the boilers and the primary
circuit low loss header. When using Hamworthy Frame
and Header Kits this pocket is provided.
Each Master Control can be configured to accept a 0-
10Volt analog signal for either load control or
temperature control.
The BMS should be configured to provide cascade
control of all Master Controls fitted to the same heating
system and facilitate load sharing via lead boiler
rotation.
All ancillary plant (primary pump and secondary circuit
pumps/valves) must be controlled via the BMS. The
BMS must ensure operation of the primary pump using
flow switches before initiating boiler operation. All plant
interlocks (pumps, pressurisation units, fire alarms etc)
must be configured to prevent boiler operation via the
0-10Volt analog signal.
8.2.6.1 Load Control
The Master control translates the analog input and
sets the boiler output (%load) accordingly. Set
parameter 14=2(for HT circuit) or 22=2(for LT circuit) -
see section 8.10.5.1
A 2V input will switch the boiler(s) on at minimum load,
9V input will switch the boiler(s) to maximum load
(parameter 15). The load between 2 & 9V is linearly
calculated. A switching hysteresis of 0.2V calculates
the switch off, hence when the input drops below 1.8V,
the boiler(s) will switch off
HAMWORTHY HEATING LTD
To prevent boiler overheating, the control can be set
to switch off at a pre-determined temperature,
regardless of the input voltage (parameter 20 (HT) or
27 (LT)).
When using a 0-10v for a Primary circuit, in addition to
setting parameter 22=2, set parameter 34=0 to
designate pump 3 as the primary pump. This will
operate the pump, whenever a demand is applied to
the boiler.
MUST be
Figure 8.2.6.1 - Load Control
8.2.6.2 Temperature Control
The Master control translates the analog input and
sets
parameter 14=3(for HT circuit) or 22=3(for LT circuit) -
see section 8.10.6.1
A 2V input will set the boiler(s) on at minimum
temperature (parameter 18(HT) or 24 (LT)). A 9V
input will set the boiler(s) to maximum temperature
(parameter 1(HT) or 3 (LT)). The temperature
between 2 & 9V is linearly calculated.
A switching hysteresis of 0.2V calculates the switch
off, hence when the input drops below 1.8V, the boiler
(s) will switch off.
When using a 0-10v for a Primary circuit, in addition to
setting parameter 22=3, set parameter 34=0 to
designate pump 3 as the primary pump. This will
operate the pump, whenever a demand is applied to
the boiler.
Figure 8.2.6.2—Temperature Control
28
MILBORNE
the boiler temperature accordingly. Set
500001130/J