Neff integrated dishwasher S9LT1F-----S4456S4GB/35

[nortonbob]

not heating water, how do you get to the heater? to test it.

 

[nortonbob]

OK< got the panels off, how to test the heater,what impedance should it be?

 

[zipper]

Impedance??
Do you mean resistance?......approximately 22 ohms.
No heat issues don't automatically mean the element is faulty.

 

[nortonbob]

Thanks mate,PCB has bad joints at relay, any tips as to soldering,??,any way to test relay without removal?.

 

[zipper]

If you want to test the relay I would advise removing it first. Alternatively you could try re-soldering the joints & see if it heats afterwards. There will be a wiring schematic on the relay body. You need a low voltage DC supply to activate the coil (usually 12v, but can also be 24v). The voltage/current ratings are printed on the relay. If the relay is 12v & you have a 12v cordless drill you could use the battery as a test supply to check if the relay is switching correctly.

 

[nortonbob]

Thanks Zipper, re-soldered the 2 relay connections that looked cracked but still no joy, how many connections to the pcb ? anything else i can remove to test? i checked the heater inputs with a 250v test probe (while running!!) no voltage shown and the machine just keeps on washing (cold).I can get it to empty playing programes so pipes are clear and supply good. THink there are 2 relays on the board?,thermal cut out somewhere? I know the wife put the machine on a high temp to kill smells ,--I blame her!!.

 

[zipper]

A bad contact on the heater relay usually results in visible burn marks on the card. Have you checked the element resistance is approx 22 ohms?
No-heat issues (on this model) can be caused by an O/C element, break or bad connection in the heater circuit, defective heater relay, faulty NTC/thermostat, under-filling, defective safety switch, or even a clogged matrix. Your model has the dreaded instantaneous water heater fitted & believe me it is a real glory to work on. The combined NTC/thermostat is mounted on top of the instantaneous water heater, the safety switch is fitted on the end between the heater terminals. Be aware the heater does not engage until 15/20mins into a program (after the initial cold rinse).

 

[nortonbob]

Thanks again Zipper, I have test gear,so will check element,I pressume the safety switch should show continuity if ok,also thermal cut out? ,no heat damage to pcb,there is a knocking noise from water supply valve on filling,been doing this for a while.How the heck does one get to the thermal cut out !!,At one time I thought to train as a service Engineer, thank God i did not,what a pig to work on.Service Engineers should design machines not factory geeks!!.Need to get this sorted to get back to classic Ducati bevel drive motor ,work of art.

 

[zipper]

If it makes a knocking sound when filling then it sounds more like you have a "water hammer" problem. This may cause under-filling & the safety switch may not activate, which in turn would result in no heat. Before you start dismantling the whole machine run a cycle, open the door after the rinse cycle & add a couple of litres of water to see if it heats up then. You may have a defective inlet valve or the matrix/pressure chamber could be blocked. To check the matrix/pressure chamber take off the LH side-plate. There are plenty of posts on here about this particular issue (some with pictures).

 

[nortonbob]

The knocking is comming from a device on the fill hose ,i did try adding a couple of litres but 1 hour later no heat. think i need to get the safety devices off the heater to check them any advice getting them off?,where is the thermostat, thanks mate.

 

[zipper]

The device you mention is an "aquastop". It is a double (failsafe closed) inlet valve which is powered open via the pcb. These do fail occasionally. Here is a set of constructional drawings for your machine http://www.neff-eshop.com/eshop/neff/gb/prodp.htm?prod=S4456S4GB/35&ESHOPTYPE=A There are several pages showing all internal components. Clicking the various part numbers will give you a description & price. The heater assembly c/w thermal devices & safety switch is shown on page 4.