30
STRATA1
3 8 & 3 8 / 4 6 C O M B I
OS
Condense
Waste
Strata 1-38
Boiler or
Strata 1-38/46
Combi
Expansion
Vessel
LSV
DOC
DOC
DOC
DOC
T
S/T
Radiator
Zone Pump 1
A Max.
HWS Primary
Pump* 2 A Max.
Under Floor Zone
VT Pump
Under Floor
Coils Zone
∆
t 10
ºc
Vertical
Low Velocity
Mixing Header
V Max 0.5m/s
U/Floor VT 1 A Max.
Mixing Valve
Calorifier or
Indirect Cylinder*
DOC
CWM
Filling
Point
Strainer
IV
IV
IV
RC
2
VS
RC
1
AAV
NRV
NRV
NRV
IV
IV
MRO3
Radiator Zone
DOC
*
SV
PS
*
Strainer
system type 6
Typical Single Strata 1 boiler installation serving domestic hotwater (not Combi) 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.
17.0 hydraulic system design (contd)
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 controls 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. Only to be used when RCI is used.
VS =
Underfloor zone VT flow sensor (supplied with MR03).
S/T =
Hot water temperature controls, either “S”, an HWS temperature sensor from MHS Boilers or “T”,
a cylinder thermostat.
PS =
Low water pressure cut off switch.
* Not applicable to Strata 1 - 38/46 Combi