Burnham Series 4N Boiler Instruccion De Instalación
8
1. BOILER PIPING
Attach supply and return piping lines and insert plugs
and bushings in connections as required. Supply and
return piping headers are detailed in Figure 2.
It is important to comply with the minimum
piping requirements in order to ensure maximum
performance and reliability on steam boilers,
particular attention should be given to the
construction of the supply header.
The nominal temperature differential between supply
and return water recommended for Burnham firetube
water boilers is 20°F. As a precaution against thermal
shock, this differential should never exceed 40°F.
When differentials in excess of 30°F are anticipated
on firebox boilers, the return water should enter the
boiler at the top fitting (normally the supply) and
the supply water should leave the boiler through
the bottom fitting (normally the return). This flow
pattern directs the return water over the relatively
cool third pass rather than directly against the rear
of the furnace.
The boiler should not be operated for any length
of time at a temperature setting that allows the
formation of condensation in the tubes or smokebox.
This generally dictates a minimum setting of
approximately 140°F on the low limit on systems
with a 20°F system differential. On cold start up,
condensation can be expected until the boiler warms
up. If formation of condensate persists, the low limit
should be adjusted upward until condensate no
longer forms.
Water boilers and low pressure steam boilers
must have a set LFH at 120° minimum to avoid
condensation. High pressure steam should have a
minimum LFH temperature of 180°F.
2. RECOMMENDED WATER BOILER
RECIRCULATION LOOP
The following guidelines relating to system water
temperature fluctuation and flow through the boiler
must be observed.
A. It is important to operate your boiler in such a
manner as to prevent temperature fluctuation of
more then 40°F at any time. Rapid temperature
changes within the boiler can create stresses
in the boiler metal. These stresses can cause
damage to the boiler by loosening tubes, or
in more severe instances can crack tube sheet
ligaments,furnaces, or waterlegs.
B. If temperature differentials approach 40°F,
to help prevent temperature fluctuations and
insure proper circulation through the boiler, a
recirculation loop as shown in Figure 10 should
be considered. The recirculation flow should be at
least 1/2 GPM/BHP at all times when the boiler is
online for operation.
3. TANKLESS HEATER
Install an automatic mixing valve at the tankless
heater outlet to avoid risk of burns or scalding due
to excessively hot water at the fixtures. Adjust and
maintain the mixing valve in accordance with the
manufacturer’s instructions.
A. If boiler is ordered with tankless heater, connect
tankless heater piping as shown in Figure 2.
B. The following guidelines should be followed when
piping the tankless heaters:
4. FLOW REGULATION
If flow through the heater is greater than its rating,
the supply of adequate hot water may not be able to keep up
with the demand. For this reason a flow regulator matching
the heater rating should be installed in the cold water line to
the heater. The flow regulator should preferably be located
below the inlet so it's not subjected to excess temperatures
that may occur during “off” periods when it is possible for
the heat to be conducted back through the supply line. The
flow regulator also limits the flow of supply water regardless
of inlet pressure variations in the range of 20 to 120 psi.
SECTION II — INSTALLATION INSTRUCTIONS
FIGURE 2
SCHEMATIC TANKLESS HEATER PIPING