IDEAL Falcon GTS 4, Установка и обслуживание

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9 Falcon GTS -
Installation & Servicing
GENERAL
8 SYSTEM DESIGN
Minimum Water Flow
Design Flow Rates
The following table gives the flow rate required for each boiler
based on a design temperature difference of 11
o
C (20
o
F) at the
maximum rated output. For hydraulic resistance see General
Data table (page 2).
Minimum Flow Rates
It may be necessary to fit a shunt pump to ensure minimum flow
rates.
Boiler Size (no of sections) 4 5 6 7 8
Normal water flow rate l/s 1.09 1.39 1.69 2.00 2.21
temperature difference 11
o
C (20
o
F) g.p.m. 14.4 18.4 22.3 26.4 29.2
Minimum water flow rate l/s 0.34 0.44 0.53 0.63 0.70
temperature difference 35 o C (63 o F) g.p.m. 4.5 5.8 7.0 8.3 9.3
System Design
Recommendations relating to water system design are
contained in BS. 5410: Part 2, BS. 6798 and BS. 6880.
System design must allow for adequate internal circulation
within the boiler and sufficient heat release from the boiler
body during and immediately after burner firing. Heating and/
or hot water controls should be interlocked electrically with the
burner, to prevent firing when the system does not demand
heat.
Depending on system design it may be necessary to interrupt
electrical supply to the burner before any mixing valves are
completely closed to the boiler flow. This will dissipate residual
heat. Also a pump overrun of at least 5 minutes is required on
plant shutdown to avoid interference trip out of the overheat
thermostat. If system return temperature remains below 30
o
C
for most of the heating period some protection from
condensation is required.
Please contact Ideal Stelrad Group for further information.
The example assumes flow rate required through
the DHW storage cylinder is less than that required
by the boiler. A combined shunt/DHW primary pump siz ed
on the minimum flow to be required MUST be fitted.
Provided adequate heat dissipation can be achieved at all
times the combined pump only may run on during the
overrun period - allowing the heating pump to switch off.
In order to achieve adequate heat dissipation into the DHW
storage cylinder, the diverter valve MUST always open
during the overrun period of 5 minutes.
Example A - Heating only utilizing a mixing valv e
Example B - Combined domestic hot w at er and heating using a mixing valve
Example C - Combined domestic hot wat er using a divert er valve, and heating using a mixing valve
Shunt
pump
Mixing valve Heating pump
Bypass Load
A shunt pump sized on the minimum flow rate required
MUST be fitted. Both heating and shunt pumps MUST run
on during the overrun period of 5 minutes.
The mixing valve MUST NOT be capable of complete
closure to bypass, in order that residual heat can be
dissipated.
DHW
storage
DHW Primary pump
Shunt
pump
Heating
pump
Bypass
Mixing valve
A shunt pump sized on the minimum flow rate required
MUST be fitted. Provided adequate heat dissipation can be
achieved at all times the shunt and DHW primary pumps
only may run on during the overrun period of 5 mins -
allowing the heating pump to be switched off. This
example assumes the DHW primary pump flow rate
required is less than that required for the shunt pump.
Load
Diverting
valve
Combined shunt and
DHW primary pump
Shunt
bypass
Bypass
Bypass
Heating pump
Load
Mixing valve
DHW
storage
Notes: Minimum static head requirements with limit thermostat set at 100ºC (212ºF) : 2.5m.
The examples illustrated are intended as a general guide only.
Ideal Stelrad Group will be pleased to advise on specific applications.
Design and minimum flow rate tables are shown in this leaflet.
FAL5816