Multifunctional Control Valve
![Multifunctional Control Valve](../../images/Text/Gas_safety/multifunctional_valve.jpg)
![Multifunctional Control Valve](../../images/Text/Gas_safety/Upperplumbers_Multifunctional_control_valve.jpg)
- Inside a boiler
- Incorporates:
- FFD with solenoid
- Appliance regulator (governor)
- Main gas valve
- Ignition device
< Go Back | 2013-03-12 |
Gas Tap
- Integral gas flow control to at least perform an on/off function
- Control of the heat input to the appliance
- Correct lubricant is a molybdenum disulphide grease
- Servicing Gas Tap :
- Make sure that knitting components are not wrongly assembled, distorted or missing
- Faults :
- Lubrication between the valve plug and the barrel
< Go Back | 2013-03-12 |
Safety Cut-off Valve
![Safety_Cut-off_Valve](../../images/Text/Gas_safety/Safety_Cut-off_Valve.jpg)
- Fitted on free-standing cookers
- Operated by a drop down lid
- Turns off the gas supply as the lid drops
- Faults
- Broken spring
- Dirt on the sitting
< Go Back | 2013-03-12 |
Solenoid Valve
![Solenoid Valve](../../images/Text/Gas_safety/Solenoid-Valve.jpg)
![Solenoid Valve](../../images/Text/Gas_safety/Upperplumbers_Solenoid_Valve.jpg)
- Used in conjunction with an Electric Switch or Thermostat
- Solenoid Valve controls the flow of gas
- Valve is closed when the current is off
- Can be operated on either AC (can be noisy) or D.C. suppliers
- May be a stand alone device e.g. gas line
- Commonly it is incorporated in a Multifunctional Control Valve
- Often joined with FSD on a cooker oven with automatic cooking
- Testing :
- Use pressure gauge to ensure the gas is allowing full gas pressure through or closing
< Go Back | 2013-03-12 |
Zero Governor
- Reduces the gas pressure to atmospheric on pre-mix burners
- In domestic appliances the Zero Governor is built into the Multifunctional Valve
- Has adjustable nut on the top
- Similar to constant pressure governor (the spring is softer)
- The outlet side of the zero governor is connected to the low pressure point of the venturi
- Fan speed can be adjusted through the use of Potentiometer
- Testing :
- Zero Governors are preset and no adjustments can be made
- Should be negative pressure reading prior to firing on the Multifunctional Gas Valve
< Go Back | 2013-03-12 |
Gas Relay Valve
- No longer used on domestic equipment
- Similar in construction to a regulator
- Relay Valve Faults :
- Blockage in the Weep Tube
- Blockage in the Thermostat
- Blockage at the Burner
- Damage to the Weep Tube causing a leak will cause the valve to stay open (fail safe relay valve overcomes this problem)
< Go Back | 2013-03-12 |