31
STRATA1
OS
AAV's
Condense
Waste
Strata 1
Boiler
Expansion
Vessel
DOC
LSV
DOC
DOC
DOC
DOC
T
S
W
Radiator
Zone
Pump
HWS Primary
Pump
Under Floor Zone
VT Pump
Under Floor
Coils Zone
∆
t 10
ºc
Low Velocity
Mixing Header
V Max 0.5m/s
U/Floor VT
Mixing Valve
Calorifier or
Indirect Cylinder
DOC
CWM
Filling
Point
Strainer
Strainer
SV
IV
IV
IV
RC
2
VS
RC
1
AAV
IV
IV
IV
MRO3
Radiator Zone
PS
IV
IV
1*
17.0 hydraulic system
design
OS=
Outside air temperature sensor. Provides outside
air temperature reference for both heating zones
MRO3=Pumps and mixer regulation control box from
MHS Boilers provides pump control for both
heating zones i.e. auto operation, frost protection
and summer stand still protection running.
Provides drive for underfloor coil zone VT mixing
valve with max flow temperature limitation set at
55ºC. Includes ratio setter for compensation of
under floor coils. Max pump motor loads 2A
RC1= RE2132 modulating room unit from MHS Boilers
provides Time & Temperature control for radiator
heating zone.
RC2= As RC1 but for underfloor coil zone.
VS=
Underfloor zone VT flow sensor (supplied with MR03)
S=
HWS sensor from MHS Boilers. Gives 24hr operation.
W/T= Alternative to "S" where "W" is a time switch in series
with a cylinder thermostat "T". Allows for timed HWS.
PS=
Low water pressure cut off switch
*1=
Filling Point. In accordance with BS 6644,
automatic pressurisation unit must be
installed when the boiler input is greater
than 60kW.
See item 17.1
Typical Single Strata 1 boiler installation serving domestic hotwater and radiator heating zone and an
underfloor coil zone all via a low velocity mixing header. The HWS will always have priority. the 2Nr
heating zones may operate independently via 2 Nr separate room units. The 2 Nr heating zones will
always be weather compensated but may have differing compensation slopes
System Type 7
