8
PISCES
MINIFILL
10.0 Determining the Cold Fill Pressure
MECHANICAL
M1/1
The Cold Fill Pressure is critical to the correct operation of any Pressurisation Unit and associated system. This pressure
needs to be calculated from the Static Pressure of the system (measured height in metres from the base of Pressurisation Unit
to the top of the highest part of the heating system, divided by 10 to convert to bar pressure), and an allowance for venting and
vapour pressure.
Therefore the Cold Fill Pressure, for a system with a maximum operating temperature up to
90ºC,
can be calculated as per
the example below:
Static Pressure
0.8 bar
(Height of 8.0metres, divided by 10)
Venting Allowance
0.3 bar
(Allowance from Table below)
Vapour Pressure
0.0 bar
(Allowance from Table Below)
Cold Fill Pressure
1.1 bar
(Summation of Static, Venting & Vapour Pressure)
Venting and Vapour Pressure Allowances
Venting Allowance
0.3
Allowance to ensure system can be correctly
vented.
Vapour Pressure
Allowance
0.0
Max Operating Temp up to 90ºC
0.2
Max Operating Temp 90ºC to 95ºC
0.5
Max Operating Temp 95ºC to 100ºC
0.8
Max Operating Temp 100ºC to 105ºC
1.2
Max Operating Temp 105ºC to 110ºC
1.6
Max Operating Temp 110ºC to 115ºC
2.0
Max Operating Temp 115ºC to 120ºC
11.1
Filling the System
The Pisces Minifill Mechanical M1/1 pressurisation manager cannot be used to fill the system; however, the Pisces
Minifill Electronic E1/1 and E1/2 pressurisation managers can be used to fill the system, as these appliances incorporate an
Anti-Water Wastage program.
For more information on the Pisces Minifill Electronic please contact MHS Boilers Sales Department.
Before the Pisces Minifill Mechanical M1/1 pressurisation manager can be commissioned, the entire Heating / Cooling /
Chilled Water system shall be filled, vented and completely flooded by a method approved by the Water Regulation Advisory
Scheme (WRAS) for the type of heating system installed.
i.e.
Domestic (
In-House
)
Fluid Category 3 (
C-3
)
Non Domestic (Other than
In-House
)
Fluid Category 4 (
C-4
)
For Category 3 systems, the approved method of filling must comprise of the following components in the arrangement
shown;
•
Control Valve incorporating a Double Check Valve on
the Mains Cold Water pipework.
•
Temporary Connecting Hose, which must be
disconnected after use.
•
Control Valve, on the heating system.
For Category 4 systems, the approved method of filling must comprise of the following components in the arrangement
shown;
•
Control Valve.
•
Strainer.
•
Verifiable Backflow Device with Reduced Pressure
Zone (RPZ Valve)
•
Incorporating a ‘Type BA’ Air Gap.
•
Tundish.
•
Control Valve.
