Specifications

Part number 550-100-090/0809
g a s -f i r e d w a t e r b o i l e r — Boiler Manual
10
Install water piping (continued)
System water piping methods
All piping methods shown in this manual use primary/
secondary connection to the boiler loop. These designs
ensure proper flow through the Ultra boiler, for the most
efficient and reliable operation of the boiler and the heat-
ing system. For other piping methods, consult your local
Weil-McLain representative or see separate Ultra boiler
piping guides.
Circulators
The boiler circulator (Taco 007 for Ultra-80 and -105; Taco 0014 for
Ultra-155, -230, and -299; Taco 2400-20 for Ultra-399) is shipped
loose. Locate it in the return piping, as shown in the appropriate pip-
ing diagram in this manual.
DO NOT use the boiler circulator in any location other
than the ones shown in this manual. The boiler circula-
tor is selected to ensure adequate flow through the Ultra
boiler.
Install the boiler circulator only on the boiler return pip-
ing. This ensures the pressure drop through the boiler
will not cause low pressure in the circulator intake.
Failure to comply could result in unreliable performance
and nuisance shutdowns from insufficient flow.
Circulator flow rate
Size circulators based on the flow rate required to achieve the tem-
perature change needed. You can closely estimate temperature rise (or
drop) through a circuit by using the following formula, where TD is
temperature rise (or drop), FLOW is flow rate (in gpm), and BTUH
is the heat load for the circuit:
FLOW =
BTUH
—–—–—–—–
TD x 500
Examples:
Consider a system loop for a system with total heating load equal to
210,000 Btuh. The desired temperature drop through the system piping
is 20°F. Then the required flow rate is:
FLOW =
210,000
—–—–—–—–
20 x 500
= 21 gpm
SIMPLIFIED: For 20° temperature drop, FLOW = MBH / 10.
Circulator head requirement
The circulator must be capable of delivering the required flow against
the head loss that will occur in the piping. Determine the pipe size
needed and the resultant head loss using accepted engineering methods.
The simplified pipe sizing here is limited to residential systems, and
does not include systems with fan coil units or radiant tubing.
The following simplified method for pipe and circulator
sizing must be limited to residential applications using
baseboard (finned or cast iron), cast iron radiators or
convectors. DO NOT apply for radiant heating, fan coil
units or commercial installations.
Simplified pipe/circulator selection
Install the boiler and piping using the recommended 1.
piping layouts beginning on page 12 and in the AD-
VANCED section of this manual.
Size the piping and components for each circuit in the 2.
space heating system using Figure 3.
At the ow rates
listed, the head loss in all piping will be 0.04 feet
per foot of pipe.
Determine the heating load (Btuh) for each circuit.a.
Calculate the flow rate for each circuit using its load. b.
To use a 20°F temperature drop, just divide the
MBH (1,000’s of Btuh) by 10.
Example — Flow for 20°F temp drop with 35,000 Btuh:
FLOW = 35 MBH / 10 = 3.5 gpm
Find the pipe size in c. Figure 3 that has a max flow rate just
larger than that required for the circuit.
Find the total equivalent length (TEL) of the circuit.d.
TEL accounts for losses through fittings and valves by
using the equivalent length of pipe that would cause the
same head loss. Add these numbers to the measured length
of the circuit to find TEL in feet.
TEL is usually close to 1.5 times the length of
the circuit for residential baseboard, radiator or
convector applications.
Measure the length of each circuit from the circulator e.
outlet back to its inlet. Then multiply this length times
1.5 to get the approximate TEL of the circuit.
Find the head loss for each circuit:f.
TEL = 1.5 X Circuit Length
(feet)
HEAD = TEL X 0.04
(feet water column)
NOTE: Size system header piping for the total flow of all g.
connected zones.
Example: 3.
For a circuit with heating load = 45,000 Btuh (= 45 MBH). a.
Measured length of circuit is 88 feet.
Flow = 45 MBH / 10 = 4.5 gpm.b.
TEL = 1.5 x 88 feet = 132 feet.c.
From d. Figure 3, select 1" pipe (max flow = 7.1 gpm).
Head loss = TEL x 0.04 = 132 x 0.04 = 5.28 feet.e.
Select a circulator that can deliver at least 4.5 gpm at a f.
head of 5.28 feet. (Read the NOTICE below.)
To use this method, limit the flow through ¾"
finned-tube baseboard to 3.9 gpm, or use 1"
baseboard and limit flow to 7.1 gpm. If the
total load of the circuit requires more flow,
split the circuit into two or more.
Also see Figure 9, page 15 for quick-selection
information for applications using Taco 007
circulators or equivalent for zone piping.
Flow rates for Figure 3 0.04 feet head loss per foot
of pipe
(140°F water)
Pipe size
(inches)
MAX Flow rate (GPM)
@ 0.04 feet per foot
Pipe size
(inches)
MAX Flow rate (GPM)
@ 0.04 feet per foot
¾
3.9
2
45
1
7.1
2½
75
1¼
16
3
140
1½
24
4
290