Matrix Installation and Operation Instructions
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11.0 DOMESTIC HOT WATER PLUMBING AND OPERATION
DHW Description of Operation
The Matrix heats domestic hot water on demand, indirectly, using a brazed plate heat exchanger. Using an
internal flow meter, the Matrix recognizes a DHW demand when the DHW flow rate is greater than 0.4 gpm. The
Matrix immediately goes into domestic mode, regardless of what other systems may have been operating, the
burner fires and the Matrix attempts to achieve a calculated set point which depends on the sensed water flow rate
and the programmed H20 setting (See Section 13.0). The H20 setting is accessed via the menu in the Matrix Fan
(blue) controller, and should be set at a value equal to (or slightly greater) than the temperature required at the hot
water fixtures, e.g. 125ºF. The Fan control will communicate to the Boiler (red) controller a boiler water
temperature set point applicable for the sensed flow rate and the H20 setting selected. The higher the flow rate
and/or H20 setting, the higher the boiler water set point (boiler water setting will not exceed the H20 setting by
more than 30ºF). NTI provides a Thermostatic Mixing Valve adjustable from 100 to 145°F; the mixing valve
shall be installed between the Matrix DHW supply fitting and the hot water supply pipe to the fixtures (See
Figures 11-1 and 11-2), thus providing user protection from scalding hot water.
Code requirements may require the maximum setting of the Thermostatic Mixing Valve to
be fixed at 120°F or lower, see “Thermostatic Mixing Valve” below and the instructions
included with the valve.
DHW Plumbing & Set-up
DHW Inlet & Outlet Connections –
The Matrix has two potable water connections, Inlet & Outlet, which exit
the left side of the Matrix Cabinet; on the inside of the cabinet the two lines are connected to the Brazed Plate
Heat Exchanger. The cold Inlet line flows through an integrated brass flow meter before connecting to the rear
fitting of the Brazed Plate Heat Exchanger. The hot Outlet line flows directly from the front fitting of the
Brazed Plate Heat Exchanger. See Figures 11-1 and 11-2 for installation details.
Thermostatic Mixing Valve
(Factory Supplied)
–
A Sparcomix AM101-US-1 is provided with your package.
This valve regulates the water temperature leaving the plate heat exchanger, and must be used in every
instance. The dial can be set to the desired temperature required. Consult the Honeywell manual SD/IS150 for
detailed instructions and settings. (Note: the valve must be set to a supply temperature of not more than 120˚F.
It is the responsibility of the installer to set the valve and remove the dial.)
Scald Hazard
- Hotter water increases the risk of scald injury. There is a hot water scald
potential if the thermostatic mixing valve is set too high. Be sure to follow the adjustment
instructions provided with the thermostatic mixing valve. Failure to follow these
instructions may result in serious injury or death.
DHW Filter / Y-Strainer
(Factory Supplied)
–
To protect the Matrix’s internal flow meter, it is important to
install the factory supplied Y-Strainer in the location shown in Figures 11-1 and 11-2; dirt and other debris can
cause the flow meter to malfunction.
Check Valve –
A check valve must be field provided and installed on the outlet of the mixing valve to prevent
expansion devises downstream from back flowing when the water pressure drops during cold water draws.
Failure to prevent the backflow will cause water to flow forward through the Matrix flow sensor, activating it,
when the cold-water draw has ended and the water pressure increases.
Throttling Valve –
Install a throttling valve, after the mixing valve, to regulate the maximum hot water flow rate.
The Combi is limited to a firing rate of 150 MBH; therefore excessive flow rates will result in cooler hot water
temperatures.
Drain and Isolation Valves –
Install drain and isolation valves on the inlet and outlet of the brazed plate heat
exchanger, as shown in Figures 11-1 and 11-2 so it can be flushed free of possible build-up caused by dirt or
hard water.
