System Water Piping Methods - Weil-McLain SlimFit 2 Series Manual

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SlimFit
COMMERCIAL CONDENSING GAS
Install water piping

System water piping methods

All piping methods shown in this manual use
These designs ensure proper flow through the SlimFit
boiler, for the most efficient and reliable operation of
the boiler and the heating system. For other piping
methods, consult your local Weil-McLain representa-
tive or see separate SlimFit boiler piping guides.
Recommended pipe sizing
Connect minimum pipe sizing shown in Figure 4 to the supply and
return connections for SF-550 and SF-750 boilers.
Suggested pipe sizing for boiler loop
Model
SF-550
SF-750
Size the piping and the boiler circulator to provide the required
temperature rise through the boiler loop. See Figure 5 for the
head loss through the boiler and minimum/maximum flow rates.
design the piping and components for a
boiler loop flow rate above or below the range given
in Figure 4. Insufficient flow will cause nuisance
outages due to limit operation. Excessive flow can
damage to the boiler heat exchanger from erosion.
Circulators
The boiler circulator must be supplied by others. Locate the boiler
circulator in the return piping, as shown in the appropriate piping
diagram in this manual.
use the boiler circulator in any location
other than the ones shown in this manual. The
boiler circulator must be selected to ensure ad-
equate flow through the SlimFit boiler.
Install the boiler circulator only on the boiler return
piping. This ensures the pressure drop through the
boiler will not cause low pressure in the circulator
intake.
Failure to comply could result in unreliable perfor-
mance and nuisance shutdowns from insufficient
flow.
A Taco model 1400-50 or equivalent will work for most boiler
loop circulator applications.
Part number 550-100-162/0815
-
FIRED WATER BOILER
(continued)
.
Boiler loop
2" or larger
2" or larger
—
Boiler Manual Series 2
Boiler head loss vs flow rate for SF-550 &
SF-750
Temp. Boiler head loss
GPM
Rise °F Feet w.c.
25 41.0 6.3
30
34.1 8.1
35
40 25.6 12.5
45 15.1
22.8
50 20.5 18.1
55
18.6 21.3
DO NOT design for flow rates
above or below the range listed
above.
* Suggested design flow rates (30°F temperature rise)
Temp. Boiler head loss
GPM
Rise °F Feet w.c.
30 46.4 6.3
35
39.8 7.6
40 34.8 9.2
50 13.0
27.8
55 25.3 15.3
60
23.2 17.9
65 21.4 20.7
70 19.9 23.6
DO NOT design for flow rates
above or below the range listed
above.
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