▶ This heater is not approved for preheated water
applications exceeding 140 °F (60 °C) for Residential
appliances, in these cases use a 3-way valve or mixing valve
must be installed before the appliance to prevent water
exceeding 140 °F (60 °C) for Residential appliances from
entering the appliance.
▶ When facing the heater, the ¾" cold connection is on the top
right and the hot connection is on the top left.
▶ Tighten all water connections with the support of a wrench,
see Fig. 28.
 Cold connection
 Hot connection
Greentherm T9900 SE/i – 6 720 813 635 (2019/03)
 Water filter
Appliance will overheat if not filled with water
▶ Ensure that the appliance is filled with water by opening a
hot water tap, before plug in the water heater to the power
▶ The use of unions when connecting to the inlet and outlet
connections is recommended. This will facilitate any
▶ Plastic or PEX type plumbing materials are not suitable for
connecting directly to or within 18" of the water heater.
▶ Although water piping throughout the building may not be
copper, we require that copper or suitably rated stainless
steel flex line be used for the water connections for 18" on
either side of the water heater (follow local codes if more
▶ Never sweat any piping directly to water connections, as
damage will occur.
▶ Keep water inlet and outlet pipes to no less than ¾"
diameter to allow the full flow capacity.
▶ If the cold and hot connections to the heater are reversed,
the heater will not function.
▶ Be certain there are no loose particles or dirt in the piping.
Blow out or flush the lines before connecting to the water
▶ Full port shutoff valves should be installed on both the cold
water supply and hot water outlet lines to facilitate
servicing the heater (see fig. 27).
▶ For installation on a private well system with a pressure
tank, the lowest pressure range setting recommended is
30-45 psi (2.06 - 3.1bar) to ensure optimal performance.