Weil-McLain SVF 1500 Manual page 16

SVF
™
Series 1
Commercial Condensing Gas-Fired Water Boiler — Boiler Manual
Install water piping
Recommended pipe sizing
Temperature rises shown apply to water only. For glycol/
water applications, the temperature rise will be different,
but the flow rate must be maintained within the range
listed. Contact the glycol supplier for calculating new
temperature rises.
Size the piping and the pumps to provide the required temperature rise.
See Figure 9 for boiler head loss curves. See Figure 10 for maximum and
minimum flow rate through the boiler as well as head loss vs flow rate.
Size system piping following Figure 11 or apply recognized engineering
practices to size the piping.
NOTE 1: Pipe sizing should be based on the desired tem-
perature rise for the system, corresponding to the recom-
mended maximum flow rate. Failure to follow these guide-
lines could result in system problems.
Figure 11
Recommended pipe sizing vs flow rate
Sch 40 Maximum
Pipe Flow rate
Diameter GPM
2 45
3 140
4 290
5 500
SVF
The boilers have 3" class 150 connections, provide
reducers to adapt from external piping to the boiler supply
and return flanged connections.
Expansion tank and make-up water
1. Ensure expansion tank size will handle boiler and system water volume
and temperature. See page 120 for boiler water content.
Undersized expansion tanks cause system water to be lost
from relief valve and make-up water to be added through
fill valve. Eventual boiler failure can result due to excessive
make-up water addition.
2. Tank must be located as shown in this manual, or following recognized
design methods. See tank manufacturer's instructions for details.
3. Connect the expansion tank to the air separator only if the separator is
on the suction side of the pump. Always install the system fill connec-
tion at the same point as the expansion tank connection to the system.
4. Most piping drawings in this manual show diaphragm expansion tanks.
See Figure 12 for piping from air separator to expansion tank and make-
up water line using a closed-type expansion tank.
5. Most chilled water systems are piped using a closed-type tank, as shown
in Figure 20, page 23.
Diaphragm (or bladder) expansion tank
1. (Figure 12) Always install an automatic air vent on top of the air separa-
tor to remove residual air from the system.
When using diaphragm or bladder tanks only — when the
boiler is installed above the system main piping, install an
automatic air vent in the top of the outgoing boiler piping
to prevent air pocketing.
16
(continued)
(continued)
Sch 40 Maximum
Pipe Flow rate
Diameter GPM
6 800
8 1650
10 3000
12 4750
The expansion tank needs to be pre-charged to
the required system fill pressure before being
connected to the system.
Closed-type expansion tank
1. See Figure 13, Alternate, for piping connections when using
a closed-type expansion tank.
2. Pitch any horizontal piping up towards tank 1 inch per 5
feet of piping. Connect to tank with at least ¾" piping to
allow room for air to rise.
DO NOT install automatic air vents on closed-
type expansion tank systems. Air must remain in
the system and return to the tank to provide its
air cushion. An automatic air vent would cause
air to leave system, resulting in water-logging the
expansion tank.
Figure 12
Expansion tank piping — diaphragm-type
expansion tank
8
From boiler/system
5
4
3
Figure 13
Expansion tank piping — closed-type
expansion tank
6
3
From boiler/system
8
1 Diaphragm-type expansion tank.
2 Closed-type expansion tank.
3 Make-up water line.
4 Fill valve, typical.
5 Air separator.
6 Tank fitting.
7 System pump (when used).
8 Automatic air vent.
7
To system
1
SVF-3039a
2
7
To system
SVF-3039b
Part number 550-100-250/0819