Help with hot water pressure washer burner system

Discussion in 'General Electronics Chat' started by Marinegrunt, Jul 14, 2017.

  1. Marinegrunt

    Thread Starter New Member

    Jul 14, 2017
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    I came across a Karcher hds 1200 hot water pressure washer that I fixed up. I was able to get the engine running so as of now it works as a cold water pressure washer. I just cant get the burner to fire. I'm far from an expert when it comes to circuits but can use a multi meter.

    I'm not getting power to the burner switch and I'm not sure why. When the pressure switch closes I get 12v at terminals 4 and 5. When flow control. closes i get 12v at terminal 6 and 7. Terminal 8 is where burner switch wire hooks into but I don't know where power comes from to supply the burner switch. I assume the burner switch would be the first point for 12v?

    It might be a shot in the dark trying to get help online especially when I'm probably not explaining everything right. I thought with a wiring diagram someone might be able to point me in the right direction. If I need to add more pictures or explain things better please let me know.

    Thank you

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  2. poolman966554

    Member

    Jan 22, 2014
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    throw a jumper across the switch to verify its not a bad switch. rinse/ repeat. Hard to tell from the resolution, and different language.

    Im an Hvac tech by trade.. ive had a couple beers, but i dont even see the gas valve in the schematic??
     
  3. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    Y1 is the fuel valve,terminals X1 11, 12...is there voltage across this when the thermostat is closed?
     
  4. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Is the fuel system it's self clear and free from obstructions. It is amazing where insects find to build their nests .
     
  5. Marinegrunt

    Thread Starter New Member

    Jul 14, 2017
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    Thanks Poolman. I tried bypassing by jumping the burner on/off switch and the thermostat but nothing. The English is the word in the middle. I should've blacked out the German to make it easier to read.

    Thanks Dodgydave. No, power is not making it to 11 and 12 or the fuel valve. There is a relay and one of the wires off the relay goes to terminal 11. There's a copper tab that connects terminal 11 and 10 together and the wire on 10 goes to the thermostat. 12v feeds the relay from terminal 1. I tested the relay and you can hear it click but I need to watch a video on how to ohm it. On the relay 85 goes to terminal 11 which should power 10 or thermostat. There's also a small wire on 85 that goes to what's called a pulse generator. 86 on relay goes to terminal 13(chemical solenoid). 87 goes through a fuse and back to voltage regular on the Vanguard engine. 30 goes to terminal 1 which supplies 12v to relay. I'm getting 12v at 30 and 87 as long as the key is on but engine isn't running. When i start engine 87 goes down to like 4v and 30 has .09 or i guess 0v. At no time does 85 and 86 get any power whether it's running or not. Should the relay open or close and supply power to 85 or 86? When I tested it the only click I got was between 85 and 86. No others would click but seems like 30 should?

    Thank You so much for the help. I hope I made sense.

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    What the parts list calls the pulse generator is the tan colored circuit board thing. The terminals have continuity on either side. The left side of each terminal connect to the right side. Each one has two screw terminals but are the same. Some terminals are connected to others via copper tabs in the center.

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  6. Marinegrunt

    Thread Starter New Member

    Jul 14, 2017
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    Thanks shortbus. Would low or now diesel to burner keep burner on/off switch or thermostat from getting juice? Or, does the fuel solenoid have to sense fuel before power is applied to the burner system? It's like 12v will go from pressure switch terminal when engaged to flow switch terminal when it's engaged and then stops. I did have the fuel pump apart to replace diaphragm. I just replaced it because I had to order other o rings and gaskets so figured it wouldn't hurt. This thing hadnt been ran in years before I got it but supposedly worked when put away.

    I did go completely through it and cleaned and flushed everything. There were mud dobber nests everywhere.

    I do wonder if you're on to something with fuel flow. I know it's clean but wonder if pump is bad or low pressure. I just assumed that the burner on/off switch would still be getting power tho so figured the problem was somewhere else. They say the pumps pump at around 100-140 psi. I guess I could take fuel line off before valve to see how fast it's pumping out. I could probably rig up a fuel pressire tester. I have an automotive one so would just need some adapters.
     
  7. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Mud daubers are exactly what I was thinking of. They seem to get in places you would never even think they could.
    You should take some better pictures of the printed circuit board, from a straight on point of view, so the part numbers can be read. May help others help you.
     
  8. Marinegrunt

    Thread Starter New Member

    Jul 14, 2017
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    Here's a picture of that circuit board. Two of the brown wires go to a low chemic lamp. The other 2 brown go to the terminal strip. The other 4 wires go to the water softener solenoid. I don't know how much it has go do with the burner system but I'm sure something.

    My order for a new relay was cancelled. I don't know if I'll be able to find a replacement. I'm guessing but it seems the relay may be the problem. Before I start the washer, if I bypass the pressure and flow switches, two relay terminals have 12v. Once I start the washer no terminals on the relay have 12v but one does have 2v.

    Does anyone know where I can get relay 0332014150? Is there a way I can wire another one to work? I was hoping to atleast try a new relay.

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  9. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    85/86 is the 12V coil, when voltage is applied terminals 87/30 will close and short together. This is an ordinary car relay from any automotive supplies. Which relay do you think is at fault?
     
  10. Marinegrunt

    Thread Starter New Member

    Jul 14, 2017
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    Relay is probably fine. It was more of a guess because I'm not good with this stuff. 85/86 both have 12v until I start washer. Sounds like that's right. I figured it's cheap so why not.

    I need to figure out what solenoid isn't working. Something is keeping power from getting to the burner system. I think that's how they're designed. Like if fuel solenoid doesn't sense enough fuel pressure it'll stay open keeping the circuit open. Same thing with low fuel sensor. I'm getting power up to terminal 7 which is flow sensor. I'm just not sure which solenoid is next in line because the circuit branches off after 7 and doesn't power terminal 8 which is burner switch.

    I don't get why the burner switch doesn't have power. It's basically the burner system on/off switch. Shouldn't one pole on the burner switch have 12v all the time?

    I'll probably end up having to take it in. There can't be much too this thing so was hoping it would be easy for someone to guide me through some testing. I realize that can be difficult over the net amd especially when trying to help a dummy like me. I like working on the mechanical side of things. I don't mind electrical I'm just clueless a lot of times. It has been a long time since I've taken anything to a shop or hired something done. I enjoy trying to figure things out but I'm just not sure what to test next. I think I maybe need to bypass the fuel related switches and just take them out of circuit for now.
     
  11. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    Does relay Y3 have 12v on it, (terminals X11,7) this has a set of contacts that change over.
     
  12. Marinegrunt

    Thread Starter New Member

    Jul 14, 2017
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    Thanks for mentioning the terminals to dumb it down for me. Terminals 11 and 7 do not have 12v. I'm guessing you can tell from the diagram but the wire going to one side of 11 comes from 85 on the relay I mentioned earlier and the other wire from 11 goes to fuel solenoid. Terminal 7 has a wire to fuel tank so probably fuel shortage switch. 7 also has a wire to chemical solenoid. If 11 had 12v I think the thermostat would get power too because there's a copper tab connecting terminals 10 and 11. If 12v is suppose to switch over to 85 on the relay and is not you might've found my problem.

    I just checked that relay again to see what has 12v. I'm only getting 12v on 87 this time. Last time I was getting 12v on 85 and 86 atleast until I started the pressure washer. Once I started it 12v dropped off completely. The 2 different results could've been something I did though but I don't think so. I think I have a 5 pin relay I can borrow from our golf cart to try. It's a generic 5 pin I got at parts store so I think it's the same as what you mentioned.

    I envy all of you who can read these diagrams and figure it all out. I tried googling what "X1" meant the other day but couldn't find anything. X1, bl, and br are all over and I have no idea what they mean.

    Thanks
     
  13. Dodgydave

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    Jun 22, 2012
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    Ok what voltages are at terminals X4,5,7?
     
  14. Marinegrunt

    Thread Starter New Member

    Jul 14, 2017
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    When i start the pressure washer terminal 4 and 5 get 12v (pressure switch). When I pull the trigger on spray wand it engages the flow switch and I then get 12v at terminals 6 and 7.

    Just to make sure I'm relaying the correct info what makes terminal 4 be X4 and not just 4? What does the X mean?

    Thanks Dave
     
  15. Dodgydave

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    Jun 22, 2012
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    X is probably for connector or terminal, if terminal 7 is at 12v the solenoid Y3 must be active, also is terminal 9 at 12V? this puts the bulb on marked Brennstoffe (fuel).
     
  16. Marinegrunt

    Thread Starter New Member

    Jul 14, 2017
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    Yes, Y3 (chemical solenoid) is active. Terminal 9 is not active. I jumped 7 to 9 to check bulb and it did light up. The fuel tank is 3/4 full.
     
  17. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    So which relay contacts are 7,8,9 looks like contacts 7,9 are not closed?
     
  18. Marinegrunt

    Thread Starter New Member

    Jul 14, 2017
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    I don't think 7 and 9 are closed. Should they be? I assumed the fuel shortage lamp being off is what I want unless something else kicks it on further down the line. I think the fuel shortage switch shuts down system if fuel is low to prevent fuel pump failure from overheating.

    On the diagram I marked burner switch in red but I think that's actually fuel shortage switch and the next -S5 is the burner switch. You probably saw that though.

    Can I just take the fuel shortage switch out of the loop for now just to see? How would I bypass it?
     
  19. Dodgydave

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    Jun 22, 2012
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    I would link terminals 7 to 10 and bypass the series contacts so K2 and Y1 will operate, and see what happens...
     
  20. Marinegrunt

    Thread Starter New Member

    Jul 14, 2017
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    When I link 7 to 10 it blows the in line fuse on the wire that runs 12v from the starter on the Briggs engine to terminal 3.

    I don't know if this will help but terminals 12-15 are connected with a copper tab. Terminal 15 has a ground wire directly to the battery. There's a something like a diode, resistor, etc (see picture) connecting 11 to 12. 11 is then connected to 10 with a copper tab. So if that diode, or whatever it is, is connecting 12 to 11 it's basically grounding terminal 10. I don't know. Just thought I'd mention what I can see. I don't get it. If I check for all the grounds by continuity I get 3 and 8-15. If I check terminal 3 for volts I get 12v. How's that possible when I get continuity checking terminal 3 with terminal 15 (ground). The wire on the other side of terminal 3 goes to the transformer.

    Should it be like that by all of the switches and solenoids doing their thing or is something just not right?
     
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