Blow down

When water evaporates, substances such as salts or silicates which do not pass into the steam remain in the boiler water. The boiler water in the pressure vessel thus continuously increases in concentration. This concentrated boiler water must be blown down regularly to prevent corrosion and deposits in the pressure vessel.

First condensate is boiler water entrained in the steam that is discharged from the steam pipe in the steam dryer.

Both the blow-down water and the first condensate are pressurised and have steam temperature. In the blow down vessel, blow-down water and first condensate are relaxed and cooled before they may be routed into the waste water system.

The advantages for you

  • High operational reliability through connection to boiler control
  • Cooling water consumption is reduced through delayed draining
  • A water level indicator increases operational reliability
  • Reduced-noise blow down possible
  • Good accessibility for maintenance

How it works

Make use of valuable energy and prevent hot water from being discharged into the sewer –  how it works:

  • A steam boiler can only begin blow down once the blow down vessel has given a release signal. This is only given when the water level in the blow down vessel is below a target level.
  • The water is only drained when the target water level is exceeded.
  • The drained water is cooled with fresh water if the drain temperature is above the target value.


We have compiled a number of documents in our Download Centre that provide you with important information about JUMAG's products and services.

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