carbon
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- Messages
- 2,997
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- S. Glos. U.K
If it was set correctly when the machine was manufactured
- Thread starter Bluemotion
- Start date
As others have said, it sounds like you have too small a jet size fitted!
If it still exists look at the plate on the chassis of the machine, it should give you the max pressure in bar or psi & the max flow rate of the pump in l/m. Some manufacturers are naughty & put on the pressure the bypass valve opens, the working pressure is probably up to 10 bar below that! Or look at the sticker on the actual pump, it should have the performance figures for the pump on it, or at least the model number for the pump from which you can get the figures online.
From the flow rate & pressure you get the jet size from tables like this.
https://www.pressure-washing.co.uk/nozzle-chart.php
If you cant get an exact match for your flow rate it's best practice to use the next larger nozzle size. Be careful not to look at US charts as they use a different jet size system!
If you've no pressure gauge a handy way to check if the washer is trying to run over pressure is to check what the running current of the motor is using a clamp meter on the motor live wire & see how it compares to the figure on the motor plate.
I've got a neighbour that brought me an ancient Karcher that was doing the same thing as yours, tripping out on the motor overload. The pressure gauge was broken so I used my clamp meter & it was running at 14.7 A! In this case it was caused by the sheer number of repair joints he had fitted to the 1/4" wash hose causing 500psi of back pressure on the pump! On a small hose dia like that any more than 1 joint is too much, he had 6 fitted! The hose is 6.35mm bore, every joint you add reduces that to 4mm & they all add up!
I fitted my own hose along with the correct size jet & it was back to running sweetly at the 12.7 amps on the motor plate! I just have to convince him that he needs to buy a new hose (he's known for being tightfisted!).
If it still exists look at the plate on the chassis of the machine, it should give you the max pressure in bar or psi & the max flow rate of the pump in l/m. Some manufacturers are naughty & put on the pressure the bypass valve opens, the working pressure is probably up to 10 bar below that! Or look at the sticker on the actual pump, it should have the performance figures for the pump on it, or at least the model number for the pump from which you can get the figures online.
From the flow rate & pressure you get the jet size from tables like this.
https://www.pressure-washing.co.uk/nozzle-chart.php
If you cant get an exact match for your flow rate it's best practice to use the next larger nozzle size. Be careful not to look at US charts as they use a different jet size system!
If you've no pressure gauge a handy way to check if the washer is trying to run over pressure is to check what the running current of the motor is using a clamp meter on the motor live wire & see how it compares to the figure on the motor plate.
I've got a neighbour that brought me an ancient Karcher that was doing the same thing as yours, tripping out on the motor overload. The pressure gauge was broken so I used my clamp meter & it was running at 14.7 A! In this case it was caused by the sheer number of repair joints he had fitted to the 1/4" wash hose causing 500psi of back pressure on the pump! On a small hose dia like that any more than 1 joint is too much, he had 6 fitted! The hose is 6.35mm bore, every joint you add reduces that to 4mm & they all add up!
I fitted my own hose along with the correct size jet & it was back to running sweetly at the 12.7 amps on the motor plate! I just have to convince him that he needs to buy a new hose (he's known for being tightfisted!).
Bluemotion
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- 364
- Location
- Holmfirth
Unfortunately I’m not going to get any play time within the next couple of weeks as it isn’t directly to hand but thank you for some interesting helpful information.
carbon
Member
- Messages
- 2,997
- Location
- S. Glos. U.K
If you are lucky some of those have a coloured marking on them that indicate the nozzle size
