Fixing old high pressure washer

[Pete.]

Status as of this morning

Ready for test-firing?

Get your umbrella out

 

[DennisCA]

Almost, the high pressure side is assembled, but not the low pressure side. It goes on the bottom of the washer so it will be fiddly to install but I didn't see going the other way would be any easier, I thought it was best to put it in the frame and do that later, or I would have a heavier and clumsier pump to maneuver into place.

 

[DennisCA]

An 075 nozzle is a little on the large size but an 07 nozzle is a little small for the specifications of this pump, an 075 with reduce the pressure slightly but should be the better choice as it wont wear the return valve as an 07 nozzle would. For me I don't rely on any machine pressure gauge to set the operating pressure, I always use an amp clamp when setting the operating pressure, then usually set it at about 0.5 amps below the motor rating.

I consulted a table and for 075 and for a pressure of either 110 or 120 bars I get a value of 17.7 or 18.5. This is liters/minute I assume. This seems to be in the right ballpark, the washer itself specifies 18l/min @ 120 bars.

An amp clamp is a good idea but more difficult when you got a 3 phase cable.

 

[brightspark]

I consulted a table and for 075 and for a pressure of either 110 or 120 bars I get a value of 17.7 or 18.5. This is liters/minute I assume. This seems to be in the right ballpark, the washer itself specifies 18l/min @ 120 bars.

An amp clamp is a good idea but more difficult when you got a 3 phase cable.

just clamp one phase cable then. all 3 will show the same reading

 

[carbon]

An amp clamp is a good idea but more difficult when you got a 3 phase cable.

No more difficult than single phase but just need to check all three phases are very similar. Each phase will be close to the current shown on the data plate of 8.7 amps when the pump is at full load.

 

[carbon]

I don't believe the return valve on this pump is at all adjustable however

Slackening the lock nut and screwing the cracked fitting further in should increase the pressure on the spring inside which then increases the pressure that the valve opens at. If this doesn't have any springs and valves inside then you may not be able to use a trigger with this machine. Some of the earlier machines didn't have unloader valves and it meant you had to be holding the lance when turning the machine on

 

[DennisCA]

OK I'll take a closer look at what is likely the unloader valve.

But if it didn't have an unloader valve though, why would that part even exist, all it does seems to be to lead water back from the high pressure side to the inlet manifold for the pistons. Doesn't make sense to me it could be anything else.

Edit:
I'm finding it quite confusing what to order or not as well. Seems like there are no complete packages. From what I can tell I need
-Hose
-Handle
-Lance
-Nozzle(s)

Found a handle + hose package from Kärcher, but it lacks the "business end" as do they all. And then I haven't been able to find the same place sell products for that. It's annoying to have to puzzle together stuff.

I know a lot of pressure washers have multi-nozzles you can change the type of spray with, are these generally inferior to a single nozzle end that you have to unscrew and screw into place?

Are there any standards to nozzles by the way or does every manufacturer do their own thing?

 

[DennisCA]

I took the unloader valve apart and sure enough there's a spring mechanism in there. That crack looks real bad on closer inspection however. I was a bit afraid of that.

 

[DennisCA]

Oh my god this was no fun to try and braze. White smoke and white deposits burst out regularly from the metal. I got the main portion of the crack covered however, I can get the nut about as far back as it went before. I might have ruined it anyway however (might have been some gasket inside it). But I could see the sunlight through the crack so it was never gonna work.

 

[carbon]

For me the more reliable nozzles are 1/4 bsp male threaded, available in different angles. The small quick release ones tend to be the hobby end of the market.
For hose you really want dn10 or 3/8 with 3/8 bsp ends to suit, single wire will be sufficient for the pressure you have
Handle or trigger gun general purpose with 3/8 bsp in and 1/4 bsp outlet
Lance 1/4 bsp with barrel nut

 

[carbon]

Something like this is more than suitable Wash gun
Im not sure if the pricing is competitive or if they sell direct

 

[Turbo]

If that unloader is duff you can fit an aftermarket one from suttner, they are normally specced to the pressure & flow of your pump.

If you just want to see if the pump makes pressure fit a blanking plug to the output & drill a hole in it. I can check roughly what hole size a 07 jet is.

I suggest you try this company for your hose, etc.
https://cleantec.biz/

I've no affiliation with them but they are great to deal with, know their stuff & offer international postage.

 

[DennisCA]

That's more decent prices than what I found the local sites for unloader valves (150-250€).

I was thinking of picking up yet another broken pressure washer I found, again for 40 euros. For spare parts and the unloader valve. But it's a bit far away, don't feel like going 100km one way to get it.

 

[DennisCA]

Someone offered me a stump of 32mm brass hex rod if I wanted to attempt to rebuild the cracked part, which I could well try. It's not a complicated part.

 

[Pete.]

Someone offered me a stump of 32mm brass hex rod if I wanted to attempt to rebuild the cracked part, which I could well try. It's not a complicated part.

You want bronze really, rather than brass.

 

[brightspark]

That's more decent prices than what I found the local sites for unloader valves (150-250€).

I was thinking of picking up yet another broken pressure washer I found, again for 40 euros. For spare parts and the unloader valve. But it's a bit far away, don't feel like going 100km one way to get it.

View attachment 398353

that looks like an interpump. i have one . you can get all the pumps hoses unloaders and valves from dual pumps ltd https://www.dualpumps.co.uk/online-ordering

 

[Guzrik]

Great project sofar.
Whatever you do; do paint one eye on the yellow cover.

 

[carbon]

You want bronze really, rather than brass.

Why, all of the commercial unloader valves are either of brass or stainless steel construction.

 

[brightspark]

Why, all of the commercial unloader valves are either of brass or stainless steel construction.

a lot of the high pressure fittings are bronze and some are stamped saying so

 

[carbon]

I’ve not seen many bronze fittings on pressure washers in the last 40 years.