Water treatment

Water usually contains oxygen and carbon dioxide. Both leads to corrosion in the steam system. The concentration of oxygen and carbon dioxide drops with increasing temperature. This effect is used in the feed water containerto degas the feed water. In depressurised vessels where the temperature is usually at 90°C to 95°C, a large part of the oxygen and the carbon dioxide is driven from the water. However, not all gases that may continue to cause damage quickly escape while they are not bound with dosed solutions.

If the temperature of the feed water container is increased to more than 103°C, the concentration of oxygen and carbon dioxide is negligible. Much less dosed solution needs to be added. The reduced salt content of the dosage also has a positive influence on the blow down intervals.

To achieve a water temperature in excess of 103°C, the water must be pressurised. We then speak of pressure degassing or full degassing - in contrast to partial degassing at less than 100°C in depressurised vessels.

The advantages for you

  • Savings in pressure degassing, particularly when there is lower consumption of dosed solutions, and a significantly lower risk of corrosion to the steam pipes and the steam boiler
  • Additionally, a high share of condensate return flow due to the higher water temperature of up to 1.6% (in a JUMAG steam boiler DG560 this corresponds to 6.5 kW) saves energy
  • JUMAG's patented regulation of the ventilation valve saves a lot of energy compared to other systems, as ventilation only takes place when there is oxygen in the system

How it works

JUMAG offers pressure degassing for all JUMAG feed water containers in combination with the latest boiler control.

  • A temperature transducer measures the temperature in the feed water container and keeps it at the desired temperature (usually 100°C) via the steam supply into the water area.
  • A pressure sensor measures the pressure in the feed water container and keeps it at the desired pressure (usually approx. 0.1 bar) via the steam supply into the steam area.
  • A magnetic valve that is opened cycled depending on the fresh water supply (and thus the supply of O2 and CO2) is used to drive out the harmful gases from the feed water container together with a rather low steam quantity.
  • The feed water container is supplemented by a relief valve that limits the pressure to 0.5 bar at most. The feed water container can thus remain free of TÜV monitoring and approval requirements. The relief valve must be designed according to the output of the connected steam boilers.
  • At high condensate return flow, the pressure in the feed water container can often increase to more than 0.5 bar. Therefore, JUMAG pressure degassing is equipped with an overflow valve that opens at a pressure between 0.2 bar and 0.5 bar to prevent frequent opening of the relief valve.
  • In case of overfilling of the feed water container, a fill level meter attached to the overflow sends a signal to the drain valve that is opened accordingly.
  • If a vacuum occurs in the vessel, a magnetic valve and a mechanical non-return valve open. The magnetic valve installed under the feed water container takes over the functions for ventilation, overpressure limitation, overflow and underpressure limitation.

Do you have questions?

Your JUMAG team is happy to assist you!

About us

For more than 40 years, we have been developing, producing and selling oil and gas-fired steam boilers.

JUMAG steam systems represent efficiency and user-friendliness.


Jumag Dampferzeuger GmbH
Badener Str. 8a
69493 Hirschberg

+49 6201 84603-0



We are happy to advise you