Primary Piping
DO NOT install automatic air vents on a
closed-type expansion tank system. Air
must remain in the system and be
returned to the expansion tank to pro-
vide an air cushion. An automatic air
vent would cause air to be vented from
the system resulting in a water-logged
expansion tank.
Circulator
The MODULATING DELTA is supplied
with a circulator that is pre-wired to allow
for domestic priority. Locate the circulator
in the return or supply piping as shown in
the piping diagrams included in this manual.
Sizing Primary Piping
See Figs: 7 through 10, pages 18 - 21, for
recommended piping arrangements based
on various applications. In all diagrams,
the space heating system is isolated from
the MODULATING DELTA using primary
/ secondary piping connections.
Size the piping and system components
required in the space heating system using
recognized design methods.
System Piping - Zone Circulators
Connect the MODULATING DELTA to
the system piping as shown in Fig. 9 page
20 when zoning with zone circulators. The
circulator supplied with the MODULAT-
ING DELTA should not be used for a heat
zone. It must supply only the primary loop.
Install a separate circulator for each zone of
space heating.
To control the zone circulators refer to Fig.
16, page 30 or Fig. 17 Page 31.
To ensure adequate flow rate through
the MODULATING DELTA, maintain a
minimum 1 inch diameter on the system
piping connecting the appliance to and
from the primary / secondary connec-
tion.
System Piping - Zone Valves
Connect the MODULATING DELTA to the
system piping with primary secondary pip-
ing as shown in Fig. 8 page 19 when zoning
with zone valves.
To control the system circulator refer to
Fig. 14, page 28.
To ensure adequate flow rate through
the MODULATING DELTA, maintain a
minimum 1 inch diameter on the system
piping connecting the appliance to and
from the primary / secondary connec-
tion.
System Piping - Radiant Heating with Mixing
Valve
Connect the MODULATING DELTA to the
system piping as shown with a radiant sys-
tem using a thermostatic mixing valve as
shown in Fig. 9 page 20. The primary / sec-
ondary piping ensures sufficient return tem-
perature to the MODULATING DELTA.
If the radiant system tubing contains no
oxygen barrier, a stainless steel heat
exchanger must be used. Failure to
install a heat exchanger could lead to
premature failure of the outer tank and
void any warranty claim.
NOTICE
NOTICE
NOTICE
CAUTION
16
