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8.1 Pyromat Eco with two heating circuits with mixer, heating water buffer cylinder and
DHW heating with DHW cylinder

ID: 4605384_1304_04

Applications

Heating system with log boiler, with one or several heating circuits with
3-way mixer, heating water buffer cylinder plus DHW heating.

Main components

■ Pyromat Eco
■ Ecotronic boiler control unit
■ Return temperature raising facility
■ Heating water buffer cylinder
■ DHW cylinder
■ Buffer cylinder control valve

Function description

In order to achieve the required set temperatures in heating circuits

or for DHW heating

, the Pyromat Eco

runs through the

following operating phases:
■ Heat up
■ Load operation
■ Residual heat utilisation
■ Drawing [heat] from the buffer cylinder
These are shown on the control unit display.

Heat up

Boiler

starts after charging and lighting the fuel. Initially, the air

dampers are zeroed.

Load operation

If the flue gas temperature exceeds 120 °C or the residual oxygen
content is less than 15 % (for 2 minutes), the air dampers enter their
controlled mode. For this, the air dampers are constantly regulated to
the respective set value via the value of the actual residual oxygen
content.
The actual flue gas temperature will be prevented from exceeding its
max. value by the flue gas fan and the adjustment of the primary air
dampers.

Residual heat utilisation

The residual heat utilisation phase begins if the flue gas temperature
falls below 100 °C. Buffer cylinder control valve

remains closed and

boiler control valve

remains fully open for as long as the boiler flow

temperature is higher than the set system temperature.

Drawing [heat] from the buffer cylinder

If the boiler flow temperature falls below the set system temperature,
the heat for heating circuits

or for DHW heating

is drawn

from heating water buffer cylinders

. For this purpose, boiler

control valve

is completely closed and buffer cylinder control valve

fully opened.

Return temperature raising facility

The Pyromat Eco

requires a minimum return temperature. When

boiler circuit pump

starts, boiler control valve

opens the path

from the central heating return to the Pyromat Eco

in line with the

increasing return temperature and closes the path from the boiler flow
to the boiler return (bypass).
As soon as boiler control valve

is fully open, buffer cylinder control

valve

takes over return temperature raising.

Charging the heating water buffer cylinder

During the combustion phase, heating circuits

are supplied

with heat first of all by boiler circuit pump

. As soon as the consum-

ers enter controlled mode, the boiler heat not required for heating pur-
poses is routed via buffer cylinder control valve

into the heating

water buffer cylinder, maintaining a precise temperature stratification.
Following burnout, the residual boiler heat is utilised by the buffer
charging management, before the consumers are supplied by heating
water buffer cylinders

Heating by the Pyromat Eco

The boiler heat is routed to the heating distributor by boiler circuit pump

if the boiler water temperature of the Pyromat Eco

exceeds

65 ºC. At this point, 3-way mixers

regulate the flow temperature

in accordance with the specified heating curve in weather-compensa-
ted mode.

Heating by the heating water buffer cylinder (heat drawn from the
buffer)

If the boiler flow temperature falls below the set system temperature,
the heat for heating circuits

or for DHW heating

is drawn

from heating water buffer cylinders