Weil-McLain UltraOil Manual page 14

water boiler
Connect water piping
DIAPHRAGM expansion tank (Figure 6)
• Make sure expansion tank size will handle boiler and
system water volume and temperature. Tank must
be located near boiler before inlet to circulator. See
tank manufacturer's instructions for details.
Undersized expansion tanks cause system
water to be lost from relief valve and
makeup water added through fill valve.
Eventual section failure can result.
CLOSED expansion tank (Figure 7)
• Ensure expansion tank size will handle boiler and
system water volume and temperature.
Undersized expansion tanks cause system
water to be lost from relief valve and
makeup water added through fill valve.
Eventual section failure can result.
• Pitch any horizontal piping up towards tank 1 inch
per  feet of piping.
14
— Boiler Manual
(continued)
Figure 6
Figure 7
Near-boiler piping, with diaphragm expansion tank
Near-boiler piping, with closed expansion tank
Part number 550-141-986/1005