Compact gas boiler THERM 20 LXZE.A with the option for heating water in an external storage tank operate in the same manner as the series of boilers only designed for heating. In addition, these boilers are completed with a three-way valve enabling the heating of hot water storage tanks. The maximum heat output of the boiler - 20.0 kW ensures that you have always enough heat and hot domestic water, thanks to the possibility of interconnecting with an indirect storage tank.

Due to wide range of models and volumes of storage tanks, this type of boiler enables to produce a relatively high volume of hot water and to satisfy both common household and those demanding clients who require a high level of comfort. The boiler is available in two versions according to the type of fuel, i.e. natural gas or propane combustion.


Recommended retail price: on request

eu_flagThe product THERM PRO 14 XZ.A complies all legislative, safety, healthy and environmental requirements of the European Union and CE mark enables the free movement of products within the market of the European Economic Area.

Emission category NOx 6 View the ErP label View the ErP label
  • The boiler contains a three-way valve for alternatively heating the heating system and the hot water storage tank
  • Water cooled low-emission burner
  • Simple and intuitive control
  • Fluent boiler output regulation
  • Can be regulated according to the spatial or outdoor temperature (equitherm regulation)
  • The boilers have a ‘low-emission burner’ with very low CO and NOx emissions
  • Can be controlled by a room thermostat or intelligent room regulator through OpenTherm+
  • As standard the boilers have a white cladding
Technical data Unit THERM 20 LXZE.A
Class of seasonal energy efficiency of heating - C
Energy efficiency class of water heating - A *
Declared loading profile - L *
Nominal thermal input power kW 22,2
Min. – max. thermal output for heating kW 8,0 - 20,0
Fuel - natural gas / propane
Gas consumption - natural gas m3/h 0,90 - 2,30
Gas consumption - propane m3/h 0,34 - 0,85
Min. – max. overpressure of heating system bar 0,8 - 3,0
Maximum input pressure of heating water °C 80
Boiler efficiency % 92
Volume of expansion unit l 7
Nominal supply voltage / frequency V/Hz 230/50~
Auxiliary electricity at rated heat input W 65
Level of coverage of electrical part - IP 44
Diameter of smoke flue mm 120
Dimensions: height / width / depth mm 725 / 430 / 300
Weight of boiler kg 37
Order number - 1039.9
* Values refer to boiler with storage tank OKH 100 NTR/HV

The time for heating weather in the storage tank from 10 °C to 60 °C

Type of storage tank Time (in minutes)
OKH 100 NTR/HV 17
OKH 125 NTR/HV 20
OKC 100 NTR 17
OKC 125 NTR 20
OKC 160 NTR 27
OKC 200 NTR 35