Diesel burner on pressure washer blowing white smoke

[reb78]

I wondered if anyone could help me troubleshoot this. I got my big heated pressure washer out the other day. It possibly hasn't been used for 2 or 3 years.

Firstly no water flowing. Took out and cleaned the inlet valves and that fixed that.

Next though, the burner wouldn't fire. I had a spark but no diesel at the nozzle. I cleaned the diesel filter. No joy. I pulled the pump and it seemed like the pump motor and fan werent turning. Freed the motor up and it started pumping diesel.

Hey presto, we had flames. But we also had a lot of smoke that stank like diesel and the water really wasn't getting very hot at all.

Pictures, machine specs amd nozzle info (there is no guarantee this is the correct nozzle but it burnt fairly cleanly before I put it away last time).



The smoke. This is while the trigger was pulled, water coming out and it should be steaming hot (it was only just warm)

The nozzle (this was dripping wet with diesel when I pulled it to inspect it so perhaps leaking?)

The air intake position (I haven't moved this)

 

[brightspark]

lack of pressure from the pump may bee and the diesel isnt atomising spraying properly. is the fan up to proper speed running

 

[reb78]

lack of pressure from the pump may bee and the diesel isnt atomising spraying properly. is the fan up to proper speed running

As far as I can tell, yes. But that's only eyeballing it and listening to it.

 

[reb78]

I've got a spare nozzle somewhere that's been sat on the shelf but I can't find it. Looked high and low. Tried a different nozzle from the boiler and it may have been a tiny bit better but it wasn't the same spec at all!

 

[reb78]

I think @carbon might have experience of these machines from memory.

 

[brightspark]

the combustion chamber isnt sooted up is it lack of airflow with it not burning properly

 

[reb78]

the combustion chamber isnt sooted up is it lack of airflow with it not burning properly

Maybe but I figured that would clear after a while?! I can take the top off though and check this.

 

[carbon]

Usually these things don’t have very large fuel filters and blocked filters can be an issue. The in-line filter is easy to check. There is a filter inside the fuel pump behind one of the caps

When refitting the filter after removal the filter needs to be rotated until it locates properly as if only fits in one position.
The burner nozzle has a filter in the rear that can easily restrict the flow of fuel. Blowing them out with compressed air doesn’t usually work. I’ve not tried cleaning them with an ultrasonic cleaner but that may work. With the filter removed from the rear if the nozzle. The filter is screwed on to the rear. When this filter is new brake cleaner will not stay inside the filter, once the filter is blocked even if it looks clean on the outside brake cleaner will not flow out of the filter.

 

[reb78]

Usually these things don’t have very large fuel filters and blocked filters can be an issue. The in-line filter is easy to check. There is a filter inside the fuel pump behind one of the caps
View attachment 518854
When refitting the filter after removal the filter needs to be rotated until it locates properly as if only fits in one position.
The burner nozzle has a filter in the rear that can easily restrict the flow of fuel. Blowing them out with compressed air doesn’t usually work. I’ve not tried cleaning them with an ultrasonic cleaner but that may work. With the filter removed from the rear if the nozzle. The filter is screwed on to the rear. When this filter is new brake cleaner will not stay inside the filter, once the filter is blocked even if it looks clean on the outside brake cleaner will not flow out of the filter.

Thanks for this. Thats the exact pump. I didn't have a spare online filter so removed and flushed the one on it. I will get a replacement though.

Weirdly, I removed that large cap and there is nothing in there at all so I suspect someone may have removed the internal filter (it came from a farm) - any ideas where I could get one?

That could mean the nozzle has crud in it. They aren't expensive so I ordered another .85 60°W last night to match the one in there.

I'll try and give it a clean as @brightspark suggests too.

 

[reb78]

The smoke is definitely white and stinks of diesel rather that black that I'd expect with lack of air.

 

[sako243]

Weirdly, I removed that large cap and there is nothing in there at all so I suspect someone may have removed the internal filter (it came from a farm) - any ideas where I could get one?

That could mean the nozzle has crud in it. They aren't expensive so I ordered another .85 60°W last night to match the one in there.

The pump looks a much smaller version of what we've got on our oil burner - that at least is available over the counter from City Plumbing. They also appear to be a more or less standardised manifold / fittings (and not hugely expensive) if you do need to replace.

 

[knighty]

change the nozzle, they're cheap on ebay etc.


it'll have small filter on the back of it, can almost grantee that'll be blocked and that's the problem

filling from cans etc. you always end up with a bit of dirt in the tank.... steam cleaners are bad for diesel bug too, because everything is so wet/humid

 

[reb78]

Thanks all. I've ordered a nozzle.

Whilst waiting I had a look in the burner. Not too dirty in there but obvious diesel pooling in the bottom.

I'd been reading that with these burners, white smoke indicated too much air. I had a fiddle with the air inlet grille and gradually closed it. Too closed and black smoke, too open and white. I managed to find a spot where there was none visible. The lance is now getting too hot or me to hold the metal part and it's just cleaned a trailer I need to get the oil pipes off of cleanly.

Hopefully with a new nozzle, filter and potentially fine adjustment of the air again it will be good to go. I need to see it more often really!! It's lack of use that's caused all this hassle!

 

[dave h 2]

it's a little late for this, but mine makes the same smoke when running out of fuel.

 

[reb78]

it's a little late for this, but mine makes the same smoke when running out of fuel.

Thanks. Tank was full and once I had cleaned the filter and line, it was running freely (that was an issue to start with but that was actually stopping it from firing at all!!)

 

[carbon]

Usually fuel in the bottom of the burner indicates a blocked nozzle or lack of ignition. Rather than allow the correct amount of fuel to be delivered a reduced flow will not atomize the fuel correctly and will have difficulty sustaining a flame resulting in unburnt fuel at the bottom. After you replace the nozzle you may have to adjust the air flow again.

 

[julianf]

the contraption is not much different from your central heating boiler - too much air normally just means for lost heat and an unstable flame.


im guessing you would realise if you had a leak in the heat exhanger, and what you were seeing was steam? but you also said it smells of diesel, so possibly not.


kerosene would burn easier, but, if your existing jet is for 35sec, 28sec fuel will possibly end up being a bit adventurous.

might be worth a quick go in testing though

 

[carbon]

im guessing you would realise if you had a leak in the heat exhanger

Yes because these usually have flow rates of over 10l/m the boiler will flood quickly and stop the air flow through the heat exchanger. If left water will soon exit via the exhaust on the top

 

[reb78]

Usually fuel in the bottom of the burner indicates a blocked nozzle or lack of ignition. Rather than allow the correct amount of fuel to be delivered a reduced flow will not atomize the fuel correctly and will have difficulty sustaining a flame resulting in unburnt fuel at the bottom. After you replace the nozzle you may have to adjust the air flow again.

Thanks. I reckon you are right and the new nozzle will change things again and need an alteration to the air input. I marked where it was (basically half open half closed) but loosening the nut means the screen will move easily. I was just fiddling today to see what things did!!

I suspect that the old/current nozzle is leaking as when i removed it last night to look), it was soaked with diesel.

Hopefully the new nozzle will get me even more heat output.

I have no other way to do it but i presume adjusting the air by looking for a clean no smoke burn is half way to being sufficient?

 

[jmp49]

Had this...

As covered above, this was down to diesel bug in the fuel, blocked fuel filter & slime in pump causing white smoke, cleaned that out and then burner jet was also plugged in its fine gauze filter and dripping so bad it stayed lit for a bit burning the dribbled diesel off after you turned it off.