Operating instructions

12
Part Number 550-142-784/0812
GWA Series 2 Gas-Fired Water Boilers – Boiler Manual
Figure 9 Boiler bypass piping — use only for high
water content systems —DO NOT use for
radiant panel systems.
Near-boiler piping continued
 Installallcomponentsspeciedaboveandadjustvalvesasdescribedtopreventlowtemperatureintheboiler.Failureto
preventlowwatertemperatureintheboilercouldcausecorrosionoftheboilersectionsorburners,resultinginsevere
personal injury, death or substantial property damage.
3 Install water piping continued
Boiler bypass method
1. ApplybypasspipingofFigure9tohighwatercontentsystems,
such as converted gravity systems.
2. The bypass arrangement shown protects the boiler from
damage caused by condensate corrosion due to low return
water temperature. This method does not provide protection
fromhightemperaturewaterbeingsuppliedtothesystem.
3. DO NOT apply this piping to radiant panel systems.
4. Adjustthebypassvalvesasindicatedbelow.
Adjust Bypass valves 1 and 2 as follows:
1. Startwithvalve1fullyclosed,valve2fullyopen.
2. Slowlyopenvalve1whileclosingvalve2.Adjustthevalvesuntil
theboilerpressure/temperaturegaugereadsapproximately60
°Fhigherthanthesystemtemperaturegauge.Asyouopen
the valves, pause long enough to allow temperatures to level
off.Ittakesawhilefortheboilerwatertemperaturetoriseas
the flow changes.
3. Bypass valve 1 controls system flow rate. Bypass valve 2
controls flow through the boiler.
4. The purpose of this piping is to cause a high enough
temperature rise in the boiler that the average temperature
willbewarmenoughtopreventcondensationofuegases.
System bypass method
1. ApplybypasspipingofFigure 8 to high water content systems,
radiantpanelsystemsoranysystemthatislikelytooperate
withlowreturnwatertemperatureforextendedperiods.
2. The bypass arrangement shown protects the boiler from
damage caused by condensate corrosion due to low return
watertemperatureandprotectslowtemperaturesystemsfrom
too high a supply temperature.
3. Adjustthebypassvalvesasindicatedbelow.
Adjust Bypass valves 1 and 2 as follows:
1. Startwithvalve2fullyclosed,valve1fullyopen.
2. Slowlyopenvalve2whileclosingvalve1.Adjustthevalves
until the boiler pressure/temperature gauge reads 160 °F or
higher.Asyouopenthevalves,pauselongenoughtoallow
temperaturestoleveloff.Ittakesawhilefortheboilerwater
temperature to rise as the flow changes.
3. Bypass valve 2 allows hot boiler outlet water to blend with
colder return water, raising the supply temperature to the boiler.
Bypass valve 1 balances the pressure drop through valve 2.
4. Thepurposeofthispipingistoraisethereturnwatertemperature
totheboilerenoughtopreventcondensationofuegases.
Figure 8 System bypass piping in boiler loop with
separate system circulator, using primary/
secondary piping.