Viessmann KOB PYROT KRT SERIES, Technical Data Manual, Page: 24 / 40

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5443 109 v1.9
Pyrot Technical Data
Safety Devices
Boiler system with return 3-way valve
To reliably prevent boiler corrosion through condensation
of the flue gases, the boiler return temperature must never
be below 149° F (65° C).
The stepless control of the PYROT rotating combustion
chamber requires a constant flow through the boiler of the
water to be heated. The boiler circuit, the boiler pump and
boiler-mixing valve must therefore be installed according
to section piping and installation of safety devices.
The boiler circuit should be designed that the temperature
difference between the boiler supply and the boiler return
temperature is equal to or less than 27° F (15° C).
The activation of the boiler pump and boiler mixing valve
is integrated in the custom control panel.
Legend
A
Nipple,
c
in. x 1
b
in.
B
Reducing coupling,
c
in. x
b
in.
C
Boiler water temperature gauge
D
Bushing
c
in. x
a
in.
E
Nipple
a
in. x 2
b
in.
F
Ball valve
a
in.
G
Pressure gauge
H
Reducing coupling
I
Reducing bushing
J
Nipple
K
Pressure relief valve, 30 psi or 60 psi
L
Safety heat exchanger connections, NPTM
b
in. 1
M
Sensor well - Safety Temperature Limiter (STB)
N
3 in. or 4 in. Boiler supply flange
2
O
Supply sensor well (sensor supplied)
P
Return sensor well (sensor supplied)
Q
3 in. or 4 in. Boiler return flange
2
R
Sensor well for thermal safety flush valve (R
b
in.)
(sensor supplied)
B
C
D
F
G
H
J
K
L
M
N
O
P
E
I
A
R
L
Q
The safety equipment for the heating installation must be
installed by the heating contractor authorized to do so.
Mechanical
Fire extinguishing water tank
The self-activating extinguishing device must be installed
next to the boiler feed system. Refer to section fire
extinguishing systems for the assembly.
The fire suppression is performed by means of an
extinguishing valve, which is not dependent on an electric
current. A float-type switch monitors the water level and
should be electrically connected (see field wiring diagram).
1
See section piping and installation of safety devices
2
3 in. boiler flange for Pyrot 150-300, 4 in. boiler
flange for Pyrot 400-540
Note: All fittings shown and sensors indicated are factory
supplied. The size and quantity are matched to the
specific boiler model.