Boiler Installation
System plumbing
Page 36
M1060008_US
v
3
3.6
System plumbing
For the heating system piping, it is possible to use either copper or iron
piping materials. The supply and return pipe should be insulated to
avoid heat loss. In systems where plastic tubing is used, it must have an
oxygen dif-fuser barrier. If non-oxygen barrier tubing is used, the boiler
must be separated from the tubing by a heat exchanger. A thermostatic
mixing valve, set to open at 140 ºF (60 ºC), is required to temper return
water to prevent cold return water from reaching the boiler. This valve
helps prevent boiler corrosion.
Plumbing diagrams --> Conceptual plumbing diagrams for the Froling
FHG are provided in Appendix 10.1 and are also available from Tarm
Biomass.
3.6.1
Safety plumbing
Overheat Loop: No Electricity:
The piping and controls must be
connected to the boiler in such a way that in the event of a power failure
there is one loop of radiation available for gravity circulation. This loop
must not be obstructed by any valves or other accessories which would
prevent gravity circulation during a power failure. The piping is plumbed
in such a way that excessive pressure will not be developed in any
portion of the boiler or system. The loop must be large enough to
dissipate at least 10% of the boiler’s maximum rated heat output,
assuming an ambient temperature of 65
º
F (18
º
C) and a mean water
temperature of 180
º
F (82
º
C).
The minimum pipe size for this loop is
¾
” (1” recommended) and if
possible, the loop should be located and pitched to maximize natural
thermal convection of the water. The loop must be positioned above the
boiler. The design of the loop must be such that it can be made
inoperative only in a deliberate manual action. If large enough, an
existing heating radiation zone may be used for the over-heat loop. The
loop must be equipped with zone valves which will open automatically
during a power failure. We recommend AUTOMAG zone valves for this
application (offered as an accessory).
Overheat Loop: With Electricity:
The Honeywell L4008B aquastat
provided with this boiler (shown at left) must be wired in parallel with
the thermostat on the zone with the most heating capacity in the main
living area (see wiring in Section 3.7.5). Upon reaching the aquastat set
point (200
º
F) the heating zone will be activated, pulling heat away from
the boiler. The home owner is alerted to a potential problem with the
boiler by an overly warm living space.
Pressure relief valve:
The boiler pressure relief valve (part #
100705
)
and pressure/temperature gauge (part #
PT1088
), must be installed as
shown in the figure to the left. Both parts are included with the boiler.
This is to ensure that excessive pressure will not be developed in the
boiler. When the system pressure reaches a maximum of 30 psi (2 bar),
the pressure relief valve opens and the heating water is released in the
form of steam. The pressure/temperature gauge can be used for reading
pressure and temperature in the boiler during a power outage.
Содержание FHG 20
Страница 2: ...Update Date May 2014 Reprint date Nov 2014...
