Viessmann Vitoflex 300-UF Series Installation And Operating Instructions Manual page 29

Vitoflex 300-UF Installation & Operating
Piping and Installation of Safety Devices
Note: To reliably prevent boiler corrosion caused by
condensation of flue gases, the boiler return
temperature must not under any circumstances be
below 150°F (65°C).
A Viessmann sized boiler pump with a boiler mixing
valve are provided according to the tables below.
The boiler circuit should be designed such that the
temperature difference between the supply and the
return temperature is equal to or less than ∆t 27°F
(15°C).
The expansion tank has to be connected to the
boiler without any isolation valves.
Safety equipment supplied by Viessmann:
- M 20 Boiler pump
- Y 20 Boiler mixing valve
- PRV Pressure relief valve, pressure set to 30 or 60 psi
- TS2430 Thermal safety flush valve R ¾ in., approved
component; special-purpose, designed for opening at
a temperature of 122 - 248°F (50 - 120°C), (safety
heat exchanger loop built into boiler). The Vitoflex
300-UF 390 and Vitoflex 300-UF 530 have two safety
heat exchanger loops and require one thermal safety
flush valve.
The Vitoflex 300-UF 720 to Vitoflex 300-UF 1250 have
four safety heat exchanger loops and require two
thermal safety flush valves.
- LWCO Low water cut-off
- PG Pressure gauge
- TG Temperature gauge (thermometer)
- SHE Safety heat exchanger, water volume 1.1 USG
(4.2L) per loop, NPTM b in.
Design Recommendation:
Thermal safety flush valve
Boiler Model Thermal safety
flush valve
UF 390
UF 530
UF 720
UF 950
UF 1250
Pressure relief valve
Boiler model
UF 390
UF 530
UF 720
UF 950
UF 1250
1 Threaded connection for supply line
2 Length of the drain pipe up to 13 ft. (4.0 m)
Water through-
put required at
TS-2430 36 psi (2.5 bar)
(Quantity) L/h
1 1637
1 2224
2 3020
2 3986
2 5246
Pressure relief valve Conbraco
30 psi
1a in.
1b in.
2 in.
2 in.
2 in.
(continued)
Customer supplied:
- PDP Pressure relief valve drain pipe
- DCW Cold water inlet, min. 36 psi (2.5 bar), max.
51 psi (3.5 bar)
- AV Air separator / vent
- EXP Expansion tank closed;
- for safety heat exchanger required (size according
to volume of safety heat exchanger loops and volume
of piping
- for heating system (optional)
- WSL Water supply line for safety heat exchanger
- WLV Water supply line for thermal run-off safety valve
- SDP Safety heat exchanger drain pipe
- SRL System return line to the boiler from the system
- SSL System supply line from the boiler to the system
- BPL Bypass line
- BR Boiler return
- BS Boiler supply
Note: The UF 1250, 30 psi will have 2 PRVs.
Supply line
WSL
GPM
7.2
R c in.
9.8
R c in.
13.3 R 1 in.
17.6 R 1 in.
23.0
R 1a in.
1
60 psi
1 in.
1a in.
1a in.
1b in.
2 in.
Mechanical
Supply line Drain pipe
WLV
R c in.
R c in.
R c in.
R c in.
R c in.
Drain pipe PDP 2
30 psi 60 psi
1b in. 1a in.
2 in.
1b in.
2b in. 1b in.
2b in.
2b in.
2
SDP
R 1 in.
R 1 in.
R 1 in.
R 1 in.
R 1 in.
2 in.
2 in.
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