servis washing machine - dispenser only partial flushing?

[shagty]

hi everyone,

i am experiencing problems with my servis washing machine and would really appreciate some help in diagnosing the cause of a fault.

the machine is a standard front loading 6 kg unit, 5-8 years old and the model ref is: m6012.

the problems started when the machine would only flush water through compartment 1 (pre wash) of the dispenser tray while the main wash powder and conditioner would remain in tray. a flashing light also appears on he display during the wash cycle.
shortly after, the heater element failed and tripped the power supply (ELCB).
i replaced the element and the water heating is restored.
however, the dispenser will still not flush the main wash powder and conditioner.

would anyone happen to know what the flashing light represents?
and what could the reason be for partial flushing?

after investing the effort into a new heater and door handle, i would prefer to repair if feasible.
your feedback would be greatly appreciated.

THIS NOTE HAS BEEN REVISED AS ITS INCORRECT
p.s the dispenser water valves are three individual solenoids for each compartment.

CORRECT NOTE:the dispenser lever is controlled by 2 no. solenoids

 

[shagty]

hi again,

after testing the solenoids, there dosnt appear to be flow when they should be energised.
does anyone know if this fault sounds familar with other models and could the control module be faulty?

any feedback would be greatly appreciated

regards

s

 

[zipper]

You may have realized that questions regarding Servis machines are not usually bombarded by response. This is mainly because the company went into liquidation in 2008 (with the loss of 150 jobs) & service info/parts are becoming increasingly difficult to source. That aside; On a wash fill cycle have you checked for voltage across the inlet valve on the main wash compartment? Or compared coil resistances on both valves? The wash valve could be defective. But what is more worrying is that you say the heater functions ok? If the machine doesn't fill water on a wash cycle the heater shouldn't energize (for obvious reasons). Either you have been extremely unlucky in that the wash valve and pressure switch both malfunctioned at the same time...or your pcb has gone west. I think I might suspect the latter.

 

[shagty]

zipper,

thanks for taking the time to offer some help.

i was aware of the organisations status - a real shame to see a UK made product forced out of the market by poor quality products from further a field.

regarding the machine, the water continues to enter the machine but only through the pre wash compartment and after a few moments when the light starts flashing. the 2 no. solenoids that drive the lever arm to divert water through main wash and conditioner compartment do not operate as required at the start of a regular wash cycle.

resiatance on each solenoid are similar at c. 1KOhms.
the voltage supply to each solenoid does not change either when the solenoids should divert the water through the correct compartment.

i think the flashing light which appears when water would normally enter the machine may be indicating a fault somewhere. just to note, the heater failed after this partial flushing occured.

there is no visible signs of damage to the module.

is ther any other test i could do to before throwing the towel in?

thanks again for your help

rgds
s

 

[zipper]

I have some difficulty in grasping your valve setup (Servis innards are not my specialty & it is virtually impossible to dig up any technical info or drawings). Do you have a hot & cold fill, or cold only? Double, triple, or separate inlet valves? Does the machine fill to correct level on pre-wash? Is it possible to hotwire the valve that doesn't work to see if you get flow when supplied with external voltage?

 

[shagty]

zipper,

i replied with additional details and uploaded images of the w/m earlier but it dosnt appear on the forum now for some reason.

hopefully works this time.

in relation to the machine, the primary water supply is dual fed.
the dispenser water supply is delivered through a diverter which is controlled by two solinoid switches through a lever arm. (my original may have confused things - there are no solenoid powered water valves on the dispenser). the piping and control arrangement are illustrated in the images that will hopefully be attached this time.

the machine appears to fill with sufficient water but this is through the pre wash compartment when it should be through the main wash compartment. the solenoid switches will not drive the lever arm to divert the water through the ciorrect compartment although it will if i manually adjust the lever arm.

i hot-wired one solenoid last night as they are rated for 220-230V. however, i may have damaged it as the MCB tripped after a bang from the solenoid.

the images will hopefully clarify the layout.

thanks again for your help.


regards
s

p.s 4 images are uploaded in two albums titled: ''servis - partial flush'' & ''partial flush 3&4 of 4''

 

[zipper]

Now we're getting somewhere...
They are not solenoids in the sense of the word. They are wax motors (a linear actuator used where a short range of motion is required). They are filled with wax & have an internal ptc which supplies a source of heat. When supplied with voltage the wax becomes fluid, expands & pushes the cylinder out to move the diverter arm. These are very common on dishwashers but not common at all washing machines. They also have a high failure rate! I reckon you need a couple of new wax motors (especially if one "popped" last night). Obviously the internal ptc has shorted out.

 

[shagty]

zipper,

i see - never knew such an actuator existed.
they are rare for sure as I cant seem to locate them on the web.

in order to determine if the module is at fault, i monitored the voltage at each motor during this phase and it is constant at 1 to 2 volts from memory. the module should energise at least one wax motor at the beginning of a wash cycle so I assume there would be a rise in supply voltage.

based on the following electrical characteristics, should the supply voltage be 120V to operate?

0.12A (wax motor stamp)
1 kOhms (meter reading)

i am not sure if this is the appropriate test method?


thanks for your help s

 

[zipper]

Now this is getting interesting...(but it is also going from bad to worse).
This is the only place I could find an identical wax motor http://www.partwizard.net/product/20510/20085# Unfortunately it's in the US. As are these ones on ebay http://shop.ebay.co.uk/?_from=R40&_trksid=p3907.m570.l1313&_nkw=12002535&_sacat=See-All-Categories# These particular wax motors are made by a company called Eltek (Italy) so they should be available someplace in Europe. I would also agree that ohms law would seem to dictate a 120v supply but all the wax motors I have seen earlier (mainly on Asko dishwashers) were 230v, which is also the rating on yours. But even if they were 120v you are not seeing anywhere near that on the wax motor terminals, which leads me to believe that the problem lies in the pcb. At a push you could just dump the powder in the pre-wash tray??... at least you'd be able to wash a few clothes while thinking about the next step to take. But I think I would leave the shorted wax motor out of circuit for the time being. Maybe you would be able to track down a scrap machine or second hand spares someplace??

 

[shagty]

zipper,

a trip to a recycling centre/scrap yard for spares certainly has some merit, but considering these machines dont appear to be very common, it could turn out to be a fruitless task. I might just bite the bullet and buy new.

thanks a million for taking the time over the last few days for sharing your in-depth knowledge and helping diagnoise the most likely fault.


regards

s

 

[zipper]

I saw a few second hand Servis washers for sale on ebay UK today, some working...some not. I didn't run across your particular model, but that doesn't mean the detergent dispensers are any different. You might be lucky & find one complete with good wax motors. That would just leave you with the suspect pcb issue & there were lots of those for sale on ebay (most described by part number only). You never know your luck?

 

[shagty]

hi,

there sure is a good variety of service machines and spares on offer through ebay. however, logistics is an issue for me as they all appear to be based in mainland Britain.

anyhow, thanks for the suggestion.

regards,

s