20th November 2019, 21:03
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#16
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Give to Learn
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Join Date: Aug 2010
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Quote:
Quote:
Originally Posted by Devilish
Correct Ian.
For starters, the problem is not the water pump. 1/It has passed the start up test and running, otherwise it would shut down after a few seconds. 2/The FBH is not firing up for its poor performance to cause shutdown.
Water pump interruption failure to start
After the air fan is started for about 3 seconds, the PCB tests the water pump current draw, if the PCB detects a problem with the water pump current draw, it switches off the FBH immediately, then purges. Regardless of the water pump looking like it is pumping enough water when 12v is applied.
The PCB however can be misled, causing it to shutdown.
A FBH can fire up, then go into overheat shutdown. Either the water pump on board PCB has a fault, and is sending false information to the FBH PCB. Or the Water pump is drawing the correct amount of current but the impeller is seized or sluggish.
Water pump interruption failure to start with a good water pump
The PCB fails to send current test signal to the water pump.
After around 2 minutes, the glow plug is switched off, and the PCB requests flame condition, if the PCB does not get the reply within the software parameters, the PCB shuts down the FBH, and purges the combustion chamber.
Resistance testing is a good guideline, the only way I would pay for a used glow plug is after I see it fire up a FBH.
Using a known working PCB to test run a FBH will do diddly to the PCB, it will just record the faults.
MO. Try both plugs in a FBH using the known working PCB, (If you are certain it has not developed a fault). if it does not fire up, Voila.
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Nice one Mr D I knew you or rob would have the answers for the OP and it did not take long  |
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