Backfitting


 

 

  • We carry out backfitting of your installations, in line with standard EN 746-2
  • Standard IN 746-2 includes:
  1. Obligation to mount upstream a stopping valve of gas (1/4 turn - standard EN331)
  2. Obligation to place immediatly downstream from a stopping valve a gas filter (if by-pass filter applicable, it must comprise equivalent filter)
  3. Obligation to install a pressure automatic-controller equiped with a safety valve and a blow-off valve with manual rearmement (the adjustement of the pressure automatic-controller can be done only with one suitable tool)
  4. Obligation, at the time of the setting up of safety of all equipment, to have a double stopping of the gas line by solvenoid valve of safety, generally of class "A" according to the standard "EN 161", gone up in series.
  5. Obligation to have a controlling system of tightness for the thermal flows above 1200kW passing by this group of valves.
  6. Obligation to check the response of the airflow sensor of air before starting.
  7. On the level of the mixer, the backflows of air inn gas (or inversely) must be avoised, so it's recommended to install a check valve on the air feed and the gas feed before the mixer.
  8. The mixture piping must be shortest.
  9. The installation of a flame arrestor closest to the burners.
  10. The by-pass should not be installed in parallel of any safety system.

Example



A Stop Valve (1/4 turn) conforms to the standard EN331
B Gas filter
PI 1G01 Manometer 0...6Bar + valve
PCV 1G01 Gas primary regulator with safety valve and blow-off valve with manual reset
PI 1G02 Manometer 0...250mBar + valve
PSL 1G01 Mini Gas pressure switch
SV 1G01 Double-solenoid valve - Class A
XSV 1G01 Control system of tightness
ZSL 1G01 Position sensor - double solenoid closed
ZSH 1G01 Position sensor - double solenoid open
PSH 1G01 Maxi Gas pressure switch
C Gas check valve
FAN 1A01 Combustion air fan + filter
D Sectionnal valve (1/4 turn)
E Air check valve
SV 1A01 3-ways solenoid valve for test mini-air pressure switch
PSL 1A01 Mini Air pressure switch
MIX 1AG01 Air/Gaz mixer
F Sectional valve (1/4 turn)
PAH 1AG01 Maxi mixture pressure switch
G Sectional valve (1/4 turn)
H Modulating valve (auto or manu)
PI 1AG01 Manometer 0...125mBar + valve
I Flame arrestor (ARF) to be established closest the burners. One by zone at least
J Relief membrane