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Power washer fault, help please
I have a B&Q PP power washer that has given sterling service for quite
a while now, however it's just stopped working with what I suspect may be a simple to cure fault. The fault is that it simply doesn't run now when you press the trigger on the spray. It used to have the standard way of working such that the motor only ran when you press the trigger. It went intermittent for a while, you'd press the trigger and the motor would be hesitant for a while and then run continuously. Now it doesn't start at all. I'm pretty sure that there's simply no power getting to the motor, whatever cuts it off when it's not spraying is cutting it off all the time. Inside the case (well, when you take the top cover off) there is one adjustment, a spring loaded plunger comes out of the high pressure delivery connection and pushes something inside the plastic box which also has the On/Low/High control going into it. This plunger can have its length adjusted. Can anyone explain what it's for and how it should be adjusted? Any other ideas as to what might be wrong would be welcome. I'm quite happy to take it apart further if necessary, if it's a write off I won't be so unhappy, it's earned its keep already. -- Chris Green |
#2
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wrote in message ... I have a B&Q PP power washer that has given sterling service for quite a while now, however it's just stopped working with what I suspect may be a simple to cure fault. The fault is that it simply doesn't run now when you press the trigger on the spray. It used to have the standard way of working such that the motor only ran when you press the trigger. It went intermittent for a while, you'd press the trigger and the motor would be hesitant for a while and then run continuously. Now it doesn't start at all. I'm pretty sure that there's simply no power getting to the motor, whatever cuts it off when it's not spraying is cutting it off all the time. Inside the case (well, when you take the top cover off) there is one adjustment, a spring loaded plunger comes out of the high pressure delivery connection and pushes something inside the plastic box which also has the On/Low/High control going into it. This plunger can have its length adjusted. Can anyone explain what it's for and how it should be adjusted? Any other ideas as to what might be wrong would be welcome. I'm quite happy to take it apart further if necessary, if it's a write off I won't be so unhappy, it's earned its keep already. -- Chris Green Not sure if yours is the same but on my alty pressure washer the spring loaded plunger you describe switches off the pump when the water in the system is up to pressure. When you press the trigger on the lance the pressure drops fractionally the plunger returns and the pump starts (This is how I think that it works anyway) When my pressure washer showed the same problem it was because the plunger had stuck in the pump of position. I had to dismantle it clean it up and WD 40 it and in fact it took several cleans before it worked reliably. Tony |
#3
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Hi Chris
Inside the case (well, when you take the top cover off) there is one adjustment, a spring loaded plunger comes out of the high pressure delivery connection and pushes something inside the plastic box which also has the On/Low/High control going into it. This plunger can have its length adjusted. Can anyone explain what it's for and how it should be adjusted? First of all, I assume that when conected to the tap water flows through the machine and the nozzle isn't blocked? I don't know this particular machine, but..... Normally these machines switch on and off with a simple pressure switch. Assuming the working pressure is 100 bar, there will be a spring loaded valve set to (say) 110 bar. When the trigger is closed, the line pressure increases, forcing the valve to open. The valve has a piston or rod attached and when the valve opens the rod moves. The rod pushes a micro switch and breaks the circuit, so the motor stops. When you pull the trigger, the line pressure drops, the valve closes, the rod moves back and the micro switch makes the circuit again. If the machine wont start it's usually because; Valve is stuck in off position - very common if the machine hasn't been used for a while. Valve set to lower than line pressure. First thing to do is check that the spring loaded plunger is free to move & not stuck. Can be limescale or detergent residue, so if you can get it apart, clean it, lubricate it then it should work. Failing that, try adjusting the plunger length. A small adjustment makes a big difference, so don't go mad! Or the microswitch is u/s. If the motor hesitates it's posible the start capacitor is faulty My guess is that the plunger is simply stuck/sticking. Dave Any other ideas as to what might be wrong would be welcome. I'm quite happy to take it apart further if necessary, if it's a write off I won't be so unhappy, it's earned its keep already. -- Chris Green |
#4
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TMC wrote:
Inside the case (well, when you take the top cover off) there is one adjustment, a spring loaded plunger comes out of the high pressure delivery connection and pushes something inside the plastic box which also has the On/Low/High control going into it. This plunger can have its length adjusted. Can anyone explain what it's for and how it should be adjusted? Any other ideas as to what might be wrong would be welcome. I'm quite happy to take it apart further if necessary, if it's a write off I won't be so unhappy, it's earned its keep already. Not sure if yours is the same but on my alty pressure washer the spring loaded plunger you describe switches off the pump when the water in the system is up to pressure. When you press the trigger on the lance the pressure drops fractionally the plunger returns and the pump starts (This is how I think that it works anyway) When my pressure washer showed the same problem it was because the plunger had stuck in the pump of position. I had to dismantle it clean it up and WD 40 it and in fact it took several cleans before it worked reliably. That sounds a fairly likely sort of explanation, thanks, I'll get daring and take it apart some more and give it a good clean. -- Chris Green |
#5
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David Lang wrote:
Hi Chris Inside the case (well, when you take the top cover off) there is one adjustment, a spring loaded plunger comes out of the high pressure delivery connection and pushes something inside the plastic box which also has the On/Low/High control going into it. This plunger can have its length adjusted. Can anyone explain what it's for and how it should be adjusted? First of all, I assume that when conected to the tap water flows through the machine and the nozzle isn't blocked? I don't know this particular machine, but..... Yes, flows as freely as it always did. Normally these machines switch on and off with a simple pressure switch. Assuming the working pressure is 100 bar, there will be a spring loaded valve set to (say) 110 bar. When the trigger is closed, the line pressure increases, forcing the valve to open. The valve has a piston or rod attached and when the valve opens the rod moves. The rod pushes a micro switch and breaks the circuit, so the motor stops. When you pull the trigger, the line pressure drops, the valve closes, the rod moves back and the micro switch makes the circuit again. If the machine wont start it's usually because; Valve is stuck in off position - very common if the machine hasn't been used for a while. It stopped working after I'd been using it for a while so that seems unlikely. Valve set to lower than line pressure. First thing to do is check that the spring loaded plunger is free to move & not stuck. Can be limescale or detergent residue, so if you can get it apart, clean it, lubricate it then it should work. Failing that, try adjusting the plunger length. A small adjustment makes a big difference, so don't go mad! Or the microswitch is u/s. If the motor hesitates it's posible the start capacitor is faulty My guess is that the plunger is simply stuck/sticking. Thanks for the explanation of how it works, all pretty straightforward really. It definitely feels to me as if the microswitch is simply not being operated. The plunger seems quite free though so maybe I'll take a look at the mechanics of how the plunger operates the microswitch. There is a minor added complexity in that the washer has a rotating 'switch' with OFF, LOW and HIGH positions, this has a shaft that goes into the same place as the plunger (e.g. where the microswitch is) so it may have some clever interaction with the plunger to adjust the output pressure. -- Chris Green |
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