Mine recently froze up. I replaced the interior high pressure hose
which had burst. The 240V pump seems good.
I have to hold down the float in the float chamber to fill it up
before it builds up enough pressure to jet water out of the lance. The
burner kicks in and smoke comes out the exhaust but the water's cold
even on max temp. Water sometimes jets out of the junction of the
cylinder head and the pump on the left hand side, by the high presure
hose outlet. I have to retighten the cylinder head to stop it. This
suggests to me some sort of blockage from the head out the lance. The
pressure guage on the head is permanently stuck at 100Bar, machine on
or off.
I can't seem to get hold of a service manual, only an operations
manual. Replacing each part by a process of elimination will be too
expensive so I'm looking for some sort of checklist. I assume that the
service manuals are available only to dealers? Any help appreciated.
Ta
Dude
I worked for Karcher UK for 8 years, so I might be able to assist :-)
Not familiar with that model, its after my time, but they all work on a
similar princople.
First question, when it was working OK, what happened when you were using it
& shut the trigger gun? Did the whole machine stop, or did the pump
continue to run & the heater stopped?
> Mine recently froze up. I replaced the interior high pressure hose
> which had burst. The 240V pump seems good.
Do you mean the hp hose that goes from the pump to the heater?
>
> I have to hold down the float in the float chamber to fill it up
> before it builds up enough pressure to jet water out of the lance. The
> burner kicks in and smoke comes out the exhaust but the water's cold
> even on max temp.
OK, we need to sort the pump side first. Forget the burner for the moment.
Is there enough water coming in to keep the tank full? The pump won't work
properly without enough water.
> Water sometimes jets out of the junction of the
> cylinder head and the pump on the left hand side, by the high presure
> hose outlet. I have to retighten the cylinder head to stop it. This
> suggests to me some sort of blockage from the head out the lance. The
> pressure guage on the head is permanently stuck at 100Bar, machine on
> or off.
Right, take the main pressure hose off the machine & run it on cold. Do you
get a steady stream of water? If so, re connect the hose & take the gun off
etc so we can find where the blockage (?) is. Process of elimination.
Bear in mind the gauge could have been buggered by the frost. The nozzle on
the end of the lance is the most likely place for a blockage.
Let me know & we will work through it.
--
Dave - The Medway Handyman
www.medwayhandyman.co.uk
Thanks for your reply. I'll have a look tomorrow when there's more
light.
As far as I recall if you switch it on it's lowest temperature without
pressing
the lance trigger, the pump stops after about 10 seconds. If you wind
up the temperature
the pump runs forever. I suppose this means it never attains its full
operating pressure
or it does and the pressure cut-off sensor is buggered. However this
theory is
contradicted by the burner igniting, which can apparently only come on
when the
"water shortage safeguard" device senses adequate flow. The high
pressure sensor being
knackered would explain the water escape from the cyilinder head.
Perhaps I'd better stop
running it otherwise I may screw the pump.
I would like to know how it works. For example what are the two
electronic devices on
the lhs of the cylinder head? I presume one is a pressure switch to
shut off the pump
at a certain pressure. What's the other one? Also the "water shortage
safeguard" device
has what appears to be a thermistor attached to it. Is that to track
temperature of water
flow back from the coil to the pump? Why are there apparently two
overflows, a skinny
transparent pipe from the top of the cylinder head and a thick black
pipe from the top rhs
of it?
My understanding is hampered by the strange translation of the
operations manual from
German to English. Eg:
While reducing the water supply at the
pump head or with the Servopress - regulation
the overflow valve opens and part
of the water flows back to the pump suck
side.
Oo-er Mrs!
Dude
Look, forget the heater entirely for the moment. Unless the pressure
problem is sorted we can't even start on the heater.
> Perhaps I'd better stop
> running it otherwise I may screw the pump.
>
> I would like to know how it works. For example what are the two
> electronic devices on
> the lhs of the cylinder head? I presume one is a pressure switch to
> shut off the pump
> at a certain pressure. What's the other one? Also the "water shortage
> safeguard" device
> has what appears to be a thermistor attached to it. Is that to track
> temperature of water
> flow back from the coil to the pump? Why are there apparently two
> overflows, a skinny
> transparent pipe from the top of the cylinder head and a thick black
> pipe from the top rhs
> of it?
Basic theory of hot water HPC's. The pump provides pressure & sends high
pressure water through the heat exchanger.
This usually has a pressure switch to stop/start the pump. Sometimes it
will use a bypass valve & flow switch.
The heat exchanger/burner/coil/whatever has a number of safety cut outs,
commonly;
1) A flow switch - unless water flows into the heat exchanger it won't
ignite.
2) A thermostat - which will cut the HE off if it gets over temperature.
3) A backflow heat sensor - if the HE overheats and very hot water starts to
get back to the pump, it will shut off the HE. These are usually not re
setable. If they trip once they are buggered.
4) A flame failure device - no flame after a certain time, it will shut off
the fuel, usually a photo cell.
As I said, and I can't stress this enough, forget the HE for the moment - it
will just confuse matters. That can't be sorted until the HP system
functions properly.
I can sort this for you, just need some more info.
ok, I've taken off the lance altogether, where it screws into the
unit.
Switch on and the pump runs endlessly and very low flow rate dribbles
out of the
lance socket. There's a lot of air swirling around the pump casing. I
don't know if that's
usual, perhaps to cool it down? Or whether the casing's cracked and
there's some
sort of air leak?
Water is constantly spitting out of the skinny transparent overflow
hose out of the top
of the cylinder head. Other than that, not much happening.
Dude
Sounds like either insufficient water supply or air getting into the pump.
Check the small hose going from the chemical valve to the pump inlet, make
sure the valve is closed & that all joints are tight.
Even a small air leak on the inlet side will cause those symptoms
> There's a lot of air swirling around the pump casing. I
> don't know if that's
> usual, perhaps to cool it down? Or whether the casing's cracked and
> there's some
> sort of air leak?
That machine has an air cooled motor, so its probably that. The back of the
motor drives the blower for thr burner, usually through a flexible collar -
check that its tight or you burner will play up.
> Water is constantly spitting out of the skinny transparent overflow
> hose out of the top
> of the cylinder head. Other than that, not much happening.
AFAIK there isn't an overflow on the cylinder head. Are you sure that isn't
the chemical inlet pipe (see above)? Position 38/39 here
http://www.sparesgiant.com/spare-part-list~DrawingCode_C~11701110_hds601cECO_04~PartCode_C~11701110.html
top right.