35Part number 550-141-850/0699
• Installation • Start-Up • Parts • Maintenance
Water piping — snow melt systemIIIi
Figure 15b Auto return temp regulation; for
outdoor reset or fixed temp
Heating zone(s)
85016
Cold
water
fill
GV Boiler
12"
max
Snow melt
heat exchanger
Figure 15a Manual bypass valves; for fixed
temp operation only
Heating zone(s)
85014b
Cold
water
fill
GV Boiler
12"
max
Snow melt
heat exchanger
Legend
1 Boiler isolation valves
2 Automatic air vent (with diaphragm-type
expansion tank), or connect to tank fitting
(closed-type expansion tank).
3 Diaphragm- or bladder-type expansion tank, if
used (For closed-type expansion tank, pipe
from top of air separator to tank fitting as in
Figure 10.)
4 Zone valve
5 System or zone circulator
6 Flow/check valve
7 Hose bibb purge valve
8 Boiler pressure/temperature gauge
9 System supply temperature gauge
12 Return temperature automatic mixing valve
Piping snow melt systems or
combination snow melt/
space heating systems
Combination snow melt/space heating systems will have
widely varying system return temperatures. So these
systems require automatic return water temperature as
shown in Figure 15a (zone-valve zoning) or Figure 15b
(circulator zoning).
Select an automatic temperature control valve or motor-
operated valve which can be adjusted to provide a return
water temperature of at least 60 °F. Any setting higher
than 60 °F will also be acceptable.
Zone-valve zoning — The suggested piping uses a separate
circulator for system circulation to assure good
temperature distribution in the system when the return
water temperature is low.
Circulator zoning — The GV internal circulators must
not be removed. Provide a separate circulator for each
zone.
The return water temperature to the
boiler must be at least 60 °F. Provide
and apply means to regulate the
return temperature. Failure to do so
can result in boiler control operation
problems, causing possible
significant property damage.