System Water Piping Methods - Weil-McLain Ultra Manual

-
gas fired water boiler
Install water piping

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 -310) is shipped loose. Locate it in the return pip-
ing, as shown in the appropriate piping 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
=
Example
:
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:
210,000
FLOW —–—–—–—–
=
20 x 500
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.
For typical residential applications, you can estimate the total equiva-
lent piping length (TEL) of a circuit as 1.5 times the measured length
of the circuit. Then use Figure 13 to determine the head loss for the
circuit.
Part number 550-100-066/0608
— Boiler Manual
(continued)
BTUH
—–—–—–—–
TD x 500
21 gpm
=
Sizing system water piping
1. See recommended piping layouts beginning on
As shown in these examples, the space heating
system must be isolated from the boiler loop by
the primary/secondary connection
2. Size the piping and components in the space heating
system using Figure 13 or other recognized method.
To use this table, select a pipe size with a flow rate just
larger than that required. The head loss for the circuit
is the value in the heading of the column selected. See
the examples in the table notes.
3. For pipe sizes up to 2 inch, ensure a minimum flow
velocity of 2 fps (feet per second) and a maximum of
4 fps. This ensures effective air removal and minimal
noise. (For type M copper piping, this means flow rates
of: 1-inch — 5.5 to 10.9 gpm; 1¼" — 8.2 to 16.3 gpm;
1½" — 11.4 to 22.9 gpm; 2" — 19.8 to 39.6 gpm.) For
larger piping, size for a maximum head loss of 4 feet per
hundred feet of pipe.
Figure 13
Head loss in type M copper pipe
Pipe size Maximum recommended water flow rate
(inches) in pipe (GPM) for head loss of either:
2.5 feet head loss per
100 feet of piping
1 7
1¼ 12
1½ 19
2 40
2½ 70
3
112
Note:
Total head loss for a piping circuit equals the loss per 100 feet
times the TEL (total equivalent length) of the circuit in feet.
TEL includes head loss for valves and fittings in equivalent feet
of piping (i.e., how much straight length of piping would cause
the same head loss as the valve or fitting).
For example, if a piping circuit has a measure length of 250 feet,
and includes valves and fittings with a total of 175 equivalent
feet, the TEL for the circuit = 250 + 175 = 425 feet.
Examples:
Consider the circuit given above, with a TEL of 425 feet. If the
flow rate required for the circuit is 21 gpm, as in the example
at left, select a pipe size from above.
Using 1½-inch pipe would cause a head loss of 4.0 feet per 100
feet of piping. Since TEL is 425 feet, head loss would be:
Head loss = 4.0 x 425 / 100 = 4.0 x 4.25 = 17.0 feet
Using 2-inch piping would cause a head loss of 2.5 feet per 100
feet of piping. Since TEL is 425 feet, head loss would be:
Head loss = 2.5 x 425 / 100 = 2.5 x 4.25 = 12.3 feet.
page 17.
.
(140°F water)
4.0 feet head loss per
100 feet of piping
9
16
23
not recommended
(velocity more than 2 fps)
91
146
15