Valve Proving System
Valve proving systems are standard on both MDFL 2800 burners. The standard model fitted is the
Landis & Staefa LDU11. (See page 18)
When the burner operating sequence is initiated the burner control box energises the proving system,
which then carries out the following checks:
The LDU11 control unit is designed to provide automatic gas valve proving (leakage test) based on
the pressure proving principle. The system comprises the control unit, which is fixed to a
bracket/terminal box assembly close to the main valve block, and a dual pressure switch which is
connected to the test space between the main valves. The unit comes pre-wired as part of the gas
train harness.
Gas valve proving is initiated automatically on completion of the burner control circuit prior to burner
start-up. The proving test is based upon the 2-stage pressure proving principal. First, the main
safety valve (V1) on the upstream side of the gas circuit is tested by evacuating the test space (via
the pilot valve V3) and by monitoring the atmospheric pressure in it, then the valves (V2 and V3) on
the burner side are tested by pressurising the test space and monitoring the gas pressure. If the
pressure increases excessively during the first test phase (TEST 1) or decreases excessively during
the second test phase (TEST 2), the control unit inhibits burner start-up and goes to lockout. The
lockout reset button lights up and signals a fault.
A programme indicator, which stops whenever a fault is signalled, indicates which valve(s) set is
leaking.
The control unit requires to be reset manually, either on the unit itself or by a remote resetting if this
has been fitted.
MDFL 2800-38 & 2800-41 Issue 1 08/08
Page 17
Содержание MDFL 2800 - 38
Страница 5: ...MGN 3300 MGN 4000 Page 4 BURNER MOUNTING ARRANGEMENT MDFL 2800 38 2800 41 Issue 1 08 08 Page 4...
Страница 7: ...MDFL 2800 38 2800 41 Issue 1 08 08 Page 6...
Страница 19: ...MDFL 2800 38 2800 41 Issue 1 08 08 Page 18 VALVE PROVING SYSTEM LDU 11 Standard fitting...
Страница 36: ...MDFL 2800 38 2800 42 Issue 2 08 08 Page 35 MODULATING CAM BOX...
Страница 50: ...MDFL 2800 38 2800 41 Issue 1 08 08 Page 49 Performance Envelopes MDFL 2800 38 MDFL 2800 41...
Страница 54: ...NOTES MDFL 2800 38 2800 41 Issue 1 08 08 Page 53...