MHG 161
MHG 161
Ionization smoke detector
Ionization smoke detector MHG 161 is a fire detector intended for automatic signalling of arising fires in cooperation with addressable Control and Indicating Equipment LITES.

It responds to both visible and invisible smoke particles (aerosols) on the principle of detection of ionization.

The MHG 161 detector is intended for co-operation with the analogue Control and Indicating Equipments (C.I.E.) MHU 110, MHU 111, MHU 115, MHU 116, MHU 117 and with the addressable C.I.E. MHU 109. The detector contains a program that evaluates the fire situation pursuant to measuring of the surrounding smoke concentration, namely in agreement with the following adjustable characteristics:

  • basic sensitivity of the detector; it monitors the surrounding smoke concentration increase compared to the quiescent state, that compensates the climatic and other influences
    (environs temperature, pressure etc.) continuously; the basic sensitivity can be adjusted in eight degrees that must be selected with reference to the detector’s combustion gas load
    that the detector responds to; the basic sensitivity can be inactivated completely, or it can be set only partial.
  • limit sensitivity; it monitors the surrounding smoke concentration without compensation of other influences; limit sensitivity can be adjusted in eight degrees; serves primarily for a
    proper function while the fire arises extremely slowly
  • reaction time; it is the verification level of the fire situation; also adjustable in eight degrees, however they can’t be expressed by a simple time stamp, because the reaction time
    depends on the time progression of the fire situation
  • watching of dusty; it monitors the quiescent level of the detector, and upon this it evaluates the dustiness rate of the optical chamber and consequently the reliability of the detector; it
    can be adjusted in seven degrees, or inactivated; it’s set considering to the dust rate around the detector and to the setting of other parameters

Further the pre-alarm sensitivity can be adjusted, it is always higher than the alarm sensitivity. The detector self regulates its internal working characteristics, if they don’t reply to the allowable tolerance, fault warnings occur.

The adjustable characteristics can be set either into a configuration program and recorded to the detector through the C.I.E. or they can be programmed right by means of the preparation MHY 535.

The detector has a built-in isolator, that in case of a short-circuit separates the shortcut part between detectors with connected isolators on the circle line. The detector is installed into the
mounting base MHY 734 or mounting base MHY 734.028 with an acoustic signalling. For installation it is possible to use the Mounting Bar MHY 736.

The detector fulfils the requirements of the standard ČSN EN 54-7.


Technical parameters
Power supply addressable C.I.E. LITES
Optical signalling a couple of red LED
Parallel signalling type LITES
Smoke sensitivity according to ČSN EN 54-7 adjustable y = 0,18 ÷ 0,83 (y = 0,33 ÷ 0,65 according to ČSN EN 54-7)
Testing test bar MHY 506, test from the C.I.E.
Protection according to ČSN EN 60529 IP 43
Radio screening degree according to ČSN EN 55 022 B-class equipment
Address setting Addressing Preparation MHY 535 in range 1 ÷ 128
Dimensions ø98 × 42 mm
Weight cca 140 g


Product is intended for operation with safe equipment in sense of ČSN EN 60950.

Working conditions
Application of the detector is in areas protected against weather conditions with classification according to ČSN EN 60721-3-3
K: climatic conditions for environment 3K5
working temperature range -25°C ÷ +70°C
max. relative humidity 95 % at 40°C
without condensation and ice accretion  
Z: special conditions 3Z1 heat radiation negligible
3Z8 irrigation water
B: biological conditions 3B1 without presence of flora and fauna
C: chemical active substances 3C2
S: mechanical active substances 3S1
M: mechanical conditions 3M2
Duration of significant temperature (45°C ÷ 70°C) 2 months/year
Duration of significant humidity (85 % ÷ 95 % / ≤ 40°C) 100 hours/year
Maximum duration of spraying 10 min/month
Air flowing max. 6 ms-1
Gust of wind lasting 2-4s max. 12 ms-1