Brochure

By-pass
from boiler
Mixed
to boiler
Return
from system
Thermostatic sensor
Three-speed
pump
Valve for natural
circulation
Valve body
Temp. gauge pocket
well (3)
Shutter
Mixed
to boiler
Return from
system
By-pass from boiler
Thermostatic sensor
Three-speed pump
Natural circulation
flapper check valve
Shut-off ball valves,
code NA39753 (1") or
NA39588 (1-1/4")
Temperature gauge
Zone of condensation
forming:
Tar deposits
Corrosion
Reduction in heat
exchanger efficiency
Flammability
Primary and
secondary air:
Combustion
efficiency
BOILER PROTECTION
RECIRCULATION AND
DISTRIBUTION UNIT
Accumulation
of ash and residues
Flue gas and
emission
control
M
SF
SR
140º F
150 psi
210º F
Dimensions
Characteristic components Hydraulic diagram
Wood biomass and condensation build-up
Wood contains a variable moisture content depending on the type (logs,
pellets, woodchips, etc.). Water vapor is released during the solid fuel
drying phase inside the combustion chamber. The presence of cold
surfaces in the boiler or flue gas chimney can lower the temperature of
the flue gas down to the dew point, causing condensation. Water vapor
condenses on the boiler surfaces, together with soot and part of the
unburnt hydrocarbons contained in the flue gas, producing tar deposits.
These substances stick to the walls of the boiler, covering most of the
inner surfaces. In addition to being dangerous due to its flammability, tar
is damaging to the integrity of the boiler and limits the efficiency of the
flue gas system waterexchanger.
By keeping the boiler walls at the highest possible temperature,
the boiler protection valve limits the formation of these substances
thereby increasing combustion efficiency, controlling emissions into the
environment and prolonging boiler life.
Code A B C D E F G
281166A 1" NPT 8
3
⁄4"5
5
⁄8"3"9
7
⁄8"1
7
⁄8"8"
281966A 1" SWT 8
3
⁄4"5
5
⁄8"3"9
7
⁄8"1
7
⁄8"8"
281176A 1
1
⁄4" NPT 8
3
⁄4"5
5
⁄8"3"9
7
⁄8"1
7
⁄8"8"
281976A 1
1
⁄4" SWT 8
3
⁄4"5
5
⁄8"3"9
7
⁄8"1
7
⁄8"8"