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6.4 Domestic Hot Water Connection
Installation and commissioning must be performed by a licensed plumbing,
heating & cooling (HVAC) company. The entire system, including all factory-
assembled components, should be inspected to ensure that everything is
working properly and that there is no leakage.
The following materials can be used in the HVAC system circuit or the
domestic hot water circuit as allow by local code:
• Copper
• Stainless steel
• Brass
• Plastic (e.g. PEX Tubing)
Depending on the materials used in the domestic hot water system (customer
installation), material incompatibility may lead to corrosion damage.
This especially applies to zinc-plated materials and materials containing
aluminum. If there is a risk of water contamination during operation, install
a suitable filter.
The maximum permissible operating overpressure indicated on the type
plate must not be exceeded. It may be necessary to mount a pressure
reducer.
Ensure that the water supply is turned on and the tank is filled before start-
up.
The domestic hot water tank must be equipped with a certified, spring-
loaded membrane safety valve on-site. A shut-off device must not be
installed between the tank and the safety valve. The operational reliability
of the valve must be checked at regular intervals. We recommend having
an annual service inspection carried out by a qualified and licensed HVAC
company.
The System M is designed to seamlessly integrate with our 85 gallon
indirect hot water tank (SMT85-1). It features a customized heat exchanger
design which maximizes the heat transfer surfaces in combination with the
HydroBox's variable speed domestic hot water tank circulating pump (M18).
The 85 gallon indirect hot water tank (SMT85-1) includes an internal 4.5kw
electrical back-up immersion heater to supplement the hot water production
when required and achieve higher temperatures required for thermal
disinfection. A DHW call is activated by the supplied sensor field-installed in
the thermal well in the SMT85-1 DHW tank. Ensure the sensor makes good
contact with the thermal well, good practice is to use a thermal paste / grease
when installing the sensor. The DHW tank maintains a set temperature as
programmed in the user interface. The DHW tank call always has priority.
Field wiring is required between the HydroBox indoor unit and the DHW tank
sensor (shipped with the System M), see section 6.6.5. Separate 120v and
240v power connections and a field supplied contactor is also required to
activate the SMT85 DHW tank and the immersion heater, see section 6.6.1.
A domestic hot water recirculation system can be used as part of the overall
system design, such as the Taco SmartPlus-e, Hot-LinkPlus-e or TacoGenie.
These systems are installed and controlled separately from the System M.
The HydroBox heat pump manager monitors and controls the production of
domestic hot water. Multiple parameters can be adjusted through the user
interface or paired smartphone app including target temperatures, speed of
production, hysteresis, grid / utility signal connections, post purge timers,
setbacks, and thermal disinfection schedules.
If using the thermal disinfection function, make sure the indirect hot water
tank's aquastat setting is set appropriately so when the thermal disinfection
function is activated a high enough tank temperature can be reached. It is
also code in most locations to install a mixing valve at the outlet of the hot
water tank to prevent scalding - check all local codes before installation.
Important:
If another indirect hot water tank is used the tank should have a
minimum of 3.3m
2
of surface transfer area and work with the head and flow
specifications of the supplied hot water tank circulating pump (M18), which
is a Taco 0034e.
6.5.1 Sensor Characteristic Curves
The temperature sensors to be connected to the heat pump manager must
correspond to the values specified in the table.
Temperature
in °F (°C)
-4
(-20)
5
(-15)
14
(-10)
23
(-5)
32
(0)
41
(5)
50
(10)
NTC-2 in kΩ
14.6
11.4
8.9
7.1
5.6
4.5
3.7
NTC-10 in kΩ
67.7 53.4 42.3 33.9 27.3 22.1 18.0
PT 1000 in kΩ
0.92 0.94 0.96 0.98
1.0
1.02 1.04
59
(15)
68
(20)
77
(25)
86
(30)
95
(35)
104
(40)
113
(45)
122
(50)
131
(55)
140
(60)
2.9
2.4
2.0
1.7
1.4
1.1
1.0
0.8
0.7
0.6
14.9 12.1 10.0
8.4
7.0
5.9
5.0
4.2
3.6
3.1
1.06 1.08 1.1
1.12 1.14 1.16 1.18 1.2
1.22 1.24
6.5 Temperature Sensor Connection
The following temperature sensors must be mounted:
• Outdoor temperature (R1) is (NTC-2)
• DHW tank sensor (R3) is (NTC-10). 20ft (6m) cable supplied,
may be extended.
The following temperature sensors are factory installed:
• Return temperature (R2) (NTC-10)
• Return line demand sensor (R2.2) (NTC-10)
• Flow rate monitoring with flow sensor (R3.1) (PT1000)
