Karcher K5.2012 Washer: Low Pressure Issues and Bypass Valve Examination

Welcome!

I have a problem with the Karcher K5.2012 washer. The topic scrolls every now and then, but I can't find any ready solution.

The washer switches on when the trigger is pressed, but usually does not pick up the right pressure. Sometimes it will catch and work nicely until I release the trigger - then low pressure again. This happens regardless of the lance - whether on Vario or Rotational.

I disassembled the washer, took out the valve described as "by-pass valve" (how will it be in Polish?), Because I suspect there is a problem here.



I even spun it, but it looks like new. I folded it and lubricated the O-rings with silicone grease. I was just surprised that it goes into the head so tightly - should it be like that?

Where else to look for a problem? I can still see in Russian films that they are grinding with sandpaper on the drill a socket for this "by-pass" valve, maybe there will be more slack there? But I'm a little afraid of such interference. The head is aluminum, but too the socket is inside of plastic (composite?).

I also dismantled the valve where the detergent dispenser is connected - it probably starts the engine. But this is probably not the lead.

Help!

Two things are worth paying attention to.
First of all, the power source - Where do you connect the washer ?? Via extension cord or directly for installation? What is the condition of the installation - old / new ?? And where are you connected to the line - or not at the end of the line.
It all matters. Why does it matter? The K5 has an induction motor - very sensitive to low voltage. By the way, quite a lot of power, on a good 50 meter extension cord it will be possible to walk, above this value problems begin. With K2-K4, this type of problem does not occur even with a large voltage drop.
Second thing, water source- What do you connect the water to ?? The source must be reasonably efficient. Once I happened to be on the washer service because something got stuck inside, and after connecting the washer to their faucet and pouring it properly, it started to work normally. (before, either it came from a low-pressure source, or at all it took water from the tank through a hose. As a result, it jammed).

Generally, K5 washers are good for washing, but they have a few drawbacks, first of all they must have a good connection to water and electricity. For the winter you need to get rid of water from them, because when left in the middle of the block breaks and water spills (or just keep in a place where there is no frost). These plastics from switching on / off switches also break very often. But then there are problems turning the washer off or on.

pawel1148 wrote:

Generally, K5 washers are good for washing, but they have a few drawbacks, first of all they must have a good connection to water and electricity.

This is not a disadvantage, but the normal performance requirements of each pressure washer.

Check the connection for tightness, maybe it draws in air with water.

So yes, the washer worked without a problem for the first 3 years, whether on a mower cable or directly to the network. I have the same water connection all the time, I live in the south of Poland so we have good quality water.

Now I tested without an extension cord, plugged directly into the contact - when the engine enters high speed it holds the power nicely, it can go on like this for a few minutes until I release the trigger. Only then is the problem to 'surprise' again. Sometimes I have to turn the Vario lance on Min-Max and it will work.

Tight connection, in the sense of the water connection to the washer, or the 'gun' itself? Because I still think if the problem is not in the gun - the O-rings on the high-pressure hose look undamaged.

Hello, has anyone solved this problem? I have the same problem, in that year my washer was still surprising after a few trigger presses, today unfortunately I do not want to surprise, it works as if at low power and low pressure, where to look for the problem?

....................

I undressed, everything looked ok, clean, nothing dirty, greased, folded and helped so much that it surprises after removing the tip and spraying with the trigger itself, after installing the tip works until the trigger is released, after pressing again there is a weak pressure, where to look?

Good day.
I have the same problem. After getting started, everything looks good. Someone has already solved this problem.


Best regards.

Hello. In my case it is similar. Weak pressure. I replaced the valves on the head with new ones, nothing helped. I combined in different ways. Different sources of energy and water. I am thinking about replacing the head, maybe new valves stick badly?

Hello
can someone send me / insert the scheme or valve number "by pass" for karcher k5.2012?
And what lubricant is best to use to lubricate this valve?

Someone solved this problem I have the same

You can see the ailment of these washers. I have the same and I don't know what to mention. there seems to be no solution.

I have the same. Same washcloth. I replaced this valve from post # 1 with a new one and no changes. The water pressure in the house is good, I connect it without an extension cord. I was in the karcher service in Krosno, the guest doesn't know what it is. In the second service, they replaced the capacitor and nothing. Szajs made in DE?

The valve is ok. Rather, there is nothing to break it. The question is, does the head body have a full aluminum or aluminum-plastic one?

Hello after a long time!

In the end, the replacement of this head helped me, but I did it on the website, a topic known to them. It turns out that it is aluminum on the outside, and has a plastic interior, which probably deforms over time and prevents the correct operation of these valves. The only way to repair it is to replace the whole thing.

In a word, it is a dud that will definitely break again in 3 years, only the next time I will know what it is and I will replace it myself.

Illustrative picture of the head I am talking about:



There is a conspiracy of silence on the forum of people who service Karcher, because the topic is popular, but nobody wants to share their knowledge.

In the end, the replacement of this head helped me, but I did it on the website, a topic known to them. It turns out that it is aluminum on the outside, and has a plastic interior, which probably deforms over time and prevents the proper operation of these valves. The only way to repair it is to replace the whole thing.

Exactly. They go to the first assembly with the material, the replacements are made of full aluminum.
Both solutions have advantages and disadvantages.

I know that it digs up the topic, but finally I managed to fix k5 2012. I greased the chemistry valve and the overpressure valve and nothing helped. I figured I would get it going, it didn't help either. I finally found something wrong. I pulled out the piston itself without a housing (it's hard to unscrew it, but it will work on a vice). I tried to put it without the O-ring - where it should move. surprisingly, I had a hard time putting it in with pliers, and it was even worse to take it out, and if I couldn't handle it, how is it supposed to work properly there? plastic in the head at this point (plastic cylinder ? ) has swollen, which is the reason for the low pressure because the valve is always open and the water is circulating in a circle. I decided to "hon" the plastic dremel, some light abrasive tip from the parside set, 10 minutes of gentle grinding with a feeling that there are no humps until you can remove the piston without much resistance (you have to check every now and then if it's ok, because if you collect too much, it will be loose ... then some lampdoktor paste for polishing the plastic and a little felt for the dremel so that there are no burrs. You know it's crazy for sure, no one normal does such things, but I put everything lubricated, and the karcher has pressure like new. how much is it from? I don't know, I washed 3 the car and 40 meters of the cube for 3 days for now and it works. Forget the replacement of valves and buying a new pressure relief valve. It will not do anything but the place where it moves, the plastic "swelled". If it does not go there without the O-ring, it is a failure By the way, how to explain that the plastic swells there and does not wear off? The O-ring is all right, and the plastic deforms from work ..... A strange thing.

It is unnecessary to open the overflow valve. The plastic has swollen because aluminum underneath it oxidizes and presses against the plastic. You've grasped the topic, but the problem will come back over time.

Hello. I had the same problem that the pressure was normal for a K5 washer and then low. In my case, it was enough to clean the overflow valve and lubricate it with silicone grease, i.e. as my bay-pass colleagues write. It is located under the water supply port. After unscrewing three 5mm Allen screws and removing this screwdriver, a hexagonal pin will appear, which can be grabbed with pliers and pulled towards you. The entire valve is seated on an O-ring. The resistance of this seal has to be overcome. I just had a problem with this valve. Greetings and good luck

Hello, I bought a new head and I do not know where this red plastic should be. Will you help?

Thank you for the topic. I bought the whole head and valve kit. I exchanged. Kercher regained the pressure. However, I have this red plastic "pad" or whatever you want to call it. Anyone know where it goes?

I found this pic on the forum

tomusyy wrote:

Thank you for the topic. I bought the entire head and valve set. I replaced it. Kercher regained his blood pressure. However, I had this red plastic "pad" or whatever you call it. Anyone know where this goes?

Is everything OK after replacing the head? In my case, the nozzle was probably the culprit, because I bought a new gun and the problem disappeared

Hello.
I have a question because I have exactly the same problem. Which piston exactly did you repair?
I already bought a new part 9.002-456.0 - but it didn't help.
I am now considering buying a new head 9.001-800.0 which is quite expensive, but then I found your post.
I am not sure which part was causing the problem in your case.
Can I send you some pictures or can you tell me what piston did you "hone" the plastic dremel, some light abrasive tip from the parts set?
Thank you

Matej

I know that it digs up the topic, but finally I managed to fix k5 2012. I greased the check valve and the overpressure valve, and nothing helped. I figured I would get it going, but it didn't help either. I finally found something wrong. I pulled out the piston itself without a housing (it's hard to unscrew it, but it will work on a vice). I tried to put it without the O-ring - where it should move. Surprisingly, I had a hard time putting it in with pliers, and it was even worse to take it out. And if I couldn't handle it, how is it supposed to work properly there? The plastic in the head at this point (plastic cylinder ?) has swollen, which is the reason for the low pressure because the valve is always open and the water is circulating in a circle. I decided to "hone" the plastic dremel, some light abrasive tip from the parts set, 10 minutes of gentle grinding with a feeling that there are no humps until you can remove the piston without much resistance (you have to check every now and then if it's ok because if you grind too much, it will be loose ... then some lamp doctor paste for polishing the plastic and a little felt for the dremel so that there are no burrs. You know it's crazy for sure, no one normal does such things, but I put everything lubricated, and the Karcher has pressure like new. How much is it from? I don't know, I washed 3 cars and 40 meters of the cube for 3 days for now and it works. Forget the replacement of valves and buying a new pressure relief valve. It will not do anything, but the place where it moves, the plastic "swelled". If it does not go there without the O-ring, it is a failure. By the way, how to explain that the plastic swells there and does not wear off? The O-ring is all right, and the plastic deforms from work..... A strange thing.[/u]

Hi I would like to ask if anyone has actually fixed the K5 because I went and got the new head as it had a small crack between the high and low pressure.
The head it was completely different to the one that was on the earlier posts and it's all plastic two piece and all the pictures I'm seeing on YouTube is different again.
The first photo is the original head and you will see the white arrows pointing at the crack.

I have it all back together again and it’s pissing water out the top of the pipe as it leaves where the motor is into the low pressure side of the head.

As you might be able to work out in the pics that the housing with the valves are has tubes for the head studs and the pic someone else had it was all molded in but aluminum. 🤷🏼‍♂️ then YouTube it was different again.

Any advise on why water is coming out??




Added after 58 [seconds]:

Hi I would like to ask if anyone has actually fixed the K5 because I went and got the new head as it had a small crack between the high and low pressure.
The head it was completely different to the one that was on the earlier posts and it's all plastic two piece and all the pictures I'm seeing on YouTube is different again.
The first photo is the original head and you will see the white arrows pointing at the crack.

I have it all back together again and it’s pissing water out the top of the pipe as it leaves where the motor is into the low pressure side of the head.

As you might be able to work out in the pics that the housing with the valves are has tubes for the head studs and the pic someone else had it was all molded in but aluminum. 🤷🏼‍♂️ then YouTube it was different again.

Any advise on why water is coming out??

I'll dig up the topic too.
Before I set about getting the washer repaired I visited 2 local service and equipment dealers. On entry I was told that the repair was not cost-effective but they could try. I paid £100 for one diagnosis the other was free. Both recommended buying a new washer .

On my own I replaced the head, I was pleased but it only helped for a week of time, then the problem returned. Replacing the gun and lances did nothing.

I took it apart again, pulled out the valve you mentioned, rubbed the plastic sleeve with coarse then fine paper, lubricated it with white grease and it has been laughing for a month now.

Thanks for your help, the washer has recovered [/code].

siwy1857 wrote:

I took it apart again, pulled out the valve you mentioned, rubbed the plastic sleeve with coarse then fine paper, lubricated it with white grease and it's been laughing for a month now.

Thanks for your help, the washer has recovered [/code]

.

Hello, are you talking about this valve?

Yes, exactly this valve. It's hard to pull out, but with the help of a vice you can pull it out.

In my case, such a thing was the reason for the lack of pressure. .

W. I have a K5.6 washer, the symptoms were that the revs waved up and down, sometimes it helped to unscrew the rotary lance for a while and put it back on. But after a while they waved again, today I took it apart and removed the part you describe, but I accidentally saw that where you connect the water hose there is a filter inserted in the middle, I took it out and it was all clogged up. The Karcher works like this and at the service centre they shouted me £750 for the repair after a phone call.
It also affects how the tip is damaged, I just did a test on 3 rotary lances, 2 rubbish. The foamer works, the cube brush works.

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