16
WATER PIPING AND CONTROLS
4.
Back Flow Preventer
: A back flow preventer (check
valve) is required by some jurisdictions to prevent water
in the system from backing up into the city water supply.
5.
Pressure Relief Valve
: The boiler pressure relief valve
is shipped separately for field installation. It is
extremely important that this is installed on the boiler
return pipe (at the rear of the boiler).
The valve is to be installed as shown in Figure 4.1
Pipe the discharge of the relief valve to within 12"
(305 mm) of the floor and close to a floor drain.
Provide piping that is the same size or larger than the
relief valve outlet.
6.
Pump
: The boiler pump is to be sized to overcome the
pressure drop of the system while providing the flow
required by the boiler.
a. The pump should be sized based on gross output of
the boiler. Table 4.3 shows the Boiler Output as
reported to the Hydronics Institute Section of AHRI.
b. The required flow is calculated based on the design
temperature difference from the return to the supply of
the boiler. For a PFW-199 with a design temperature
difference of 20°F the calculation is as follows:
Output
182,000
Required Flow =
________
=
_________
= 18.2 GPM
Δ
T
x 500
20 x 500
Figure 4.1: Relief Valve Installation - PFW-199,
PFW-210 & PFW-399
PureFire
Model
Boiler Input
Btu/hr (kW)
Gross Output
Btu/hr (kW)
PFW-199
199,000 (58.3)
183,000 (53.6)
PFW-210
210,000 (61.5)
193,000 (56.6)
PFW-399
399,000 (116.9)
373,000 (109.3)
Table 4.3: Boiler Inputs and Outputs
Pipe the discharge of the relief valve as close as
possible to the floor and away from high traffic areas.
Pipe the discharge to a floor drain. Failure to do so
may result in personal injury and/or property damage.
CAUTION
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
Pressu
re
Dro
p (
Ft
. o
f W
at
er)
PF
W
-199
PF
W
-210
PF
W
-399
Figure 4.2: PureFire Circulator Sizing Graph
Do not operate this appliance without installing the
pressure relief valve supplied with the boiler or one
with sufficient relieving capacity in accordance with
the ASME Rating Plate on the boiler heat exchanger.
WARNING
Summary of Contents for PUREFIRE PFW-199
Page 20: ...18 WATER PIPING AND CONTROLS Figure 4 3 Schematic Piping One Boiler with a Single Storage Tank...
Page 60: ...58 Figure 13 2 Heat Exchanger Burner Assembly Repair Parts REPAIR PARTS...
Page 63: ...61 APPENDIX A STATUS SCREENS APPENDIX A STATUS SCREENS...
Page 64: ...62 APPENDIX A STATUS SCREENS...
Page 65: ...63 APPENDIX A STATUS SCREENS...
Page 66: ...64 APPENDIX B USER MENU APPENDIX B USER MENU...
Page 67: ...65 APPENDIX B USER MENU...
Page 68: ...66 APPENDIX C INSTALLER MENU APPENDIX C INSTALLER MENU...
Page 69: ...67 APPENDIX C INSTALLER MENU...
Page 70: ...68 APPENDIX C INSTALLER MENU...
Page 71: ...69 APPENDIX C INSTALLER MENU...
