17
M
H
C
Boiler
AB
AB
Cold Domestic
Water in
Flow Switch
Plate heat
exchanger
Tempering Valve
Mixed Domestic
Water
Heating & Combi Circulator
3 way diverting valve
Heating System
Return
(cool)
Heating System
Supply (hot)
Throttling Valve
Two Drains for
cleaning of plate
heat exchanger
External Combi
Manifold #82470-1
Check Valve
6.3 DOMESTIC COMBI SYSTEM
((( OPTIONAL)))
The Trinity Combi is designed for installations where space is restricted. For applications where space is
not restricted, the use of an “
Indirect Water Heater”
is highly recommended.
The Trinity Combi
incorporates all the
features of the Standard
Heating version, plus External
Combi Manifold, diverting valve,
plate heat exchanger & flow
switch.
Note: The installer is
required to install the ¾” pump
flange (included in Combi kit) onto
the boiler return pipe prior to
installing the boiler; the bolts must
be inserted into the flange prior to
installing the flange.
COMBI Sequence of
operation
When water flow greater than .5
GPM passes through the flow
switch, it closes a contact to
terminals A-C on the Sentry 2100
controller. The boiler is
immediately energized (if not
already on), the 3-way diverting
valve moves to the domestic hot
water position “A”, and the circulator is energized. Hot
water is circulated through the plate heat exchanger. The
flame is modulated to maintain the “LO” setting on the
Sentry control. The Sentry uses the boiler thermister to
read the temperature of the boiler water. Space heating is
not provided during a call for domestic.
S
R
S
R
S
R
Check
Valves
Note: See page 14 for
location of expansion
tank and other
components
Insert secondary
Loop here.
See page15 & 16
Primary Loop
For multiple boilers
Boiler
3
Boiler
2
Boiler
1
Pump
3
Pump
2
Pump
1
For the state of Massachusetts
Combi must
be field equipped
with 150 PSI
relief valve as
shown (not
provided)
C
H
M
Relief
Valve
Note: Locations of plumbing connections are not
be as shown, refer to labels on boiler, contact NTI
with any questions.
