Weil-McLain 4 Series Manual page 56

®
Series 4
Sizing dire ct-connected DHW piping
Direct-connected DHW piping
For
refer to the AQUA PLUS water heater manual for
application information. Also see quick-select in-
formation on page 14 . The information here is for
other water heater designs.
When using the Ultra boiler for dedicated DHW
applications, use the circulator supplied with
the boiler (007 for Ultra-80/105; 0014 for Ul-
tra-155/230/299/310; 0013 for Ultra-399) to circu-
late to the water heater, except where higher fl ow
rates may be required for the heater used. Use the
following method to select a circulator for the water
heater on combined space heating/DHW systems.
1. To pipe the DHW tank and boiler, follow the suggested piping
diagrams beginning on page 12 .
2. Figure 55, page 57 shows the pump curves for typical DHW
circulators. Use these curves along with boiler pressure drop
data from Figure 54, page 57 to size the DHW piping and
circulator.
3. Procedure to select a DHW circulator:
:
From the water heater manufacturer's data, fi nd:
feet water column (this is H3 in the formula below).
:
Find your boiler model in Figure 54, page 57 .
Select a fl ow rate in the Flow rate column just larger than the
required boiler water fl ow rate from Step 1.
:
Read across the row selected to fi nd the boiler pressure drop,
H1, and the pressure drop in the piping, H2. Make sure to
use the copper pipe size given in column 3 when piping the
water heater.
:
Add the pressure drop across the water heater, from Step 1,
to the values of H1 and H2 for total head loss.
:
Select a circulator that can deliver the required fl ow rate,
gpm, against the total head loss found in Step 4.
:
Consider an Ultra-155 used with a water heater that requires
a fl ow of 12 gpm with boiler water at 190°F. The water heater
is to be piped as in Figure 52 .
From the example water heater manufacturer's data, the
head loss across the water heater at 12 gpm is 5.5 feet water
column.
Read down the fi rst column of Figure 54, page 57 for the
Ultra-155 until you fi nd a fl ow rate just larger than the re-
quired 12 gpm. You'll fi nd a value of 13 gpm in the third row.
At 13 gpm, with an Ultra-155, the recommended pipe size
is 1¼ inch. From the table, the head losses are:
H1 = 13.3 feet
H3 = 5.5 feet (from water heater manufacturer's data)
H = 13.3 + 3.9 + 5.5 = 22.7 feet.
total
56
gas-fired water boiler — Boiler Manual
H2 = 3.9 feet
The closest circulator selection (from Figure 55, page 57
that can deliver 12 gpm at 22.7 feet head is either a Taco
1400 (top chart) or a Taco 0013 (bottom chart).
,
Note that, if the water heater were piped as in Figure 53 ,
then H1 would be 0, so total head loss would be H2 + H3,
or 9.4 feet (3.9 + 5.5). A Taco 0010 would handle the load
if piped this way.
See previous pages in this manual for piping details
not shown below. For DHW piping as shown below,
use sizing information in Figure 54, page 57 .
Figure 52
Figure 53
)
Part number 550-100-400/0119