Washing machine NTC sensor resistance

[DIYspanner]

Bosch WAE28162GB/09

What resistance value should the sensor have at 17° C room temperature? .........I've measured 5kΩ with my meter!

The water isn't heating. I've measured the heater element resistance and that's 27Ω.

 

[Harry Bloomfield]

There are various resistance values for thermistors, but it would be a fairly safe assumption to make - that if the resistance value changed predictably, with a change in temperature, that the thermistor is OK.

 

[DIYspanner]

I found listed on eSpares for my model and the unit in the photo has 4.8k stamped on it although it may be a generic photo.

 

[Harry Bloomfield]

Bosch WAE28162GB/09

What resistance value should the sensor have at 17° C room temperature? .........I've measured 5kΩ with my meter!

The water isn't heating. I've measured the heater element resistance and that's 27Ω.

Failing to turn the heater on, could be the water level sensor, not able to detect the water level in the drum.

Is it indicating an error?

 

[DIYspanner]

Failing to turn the heater on, could be the water level sensor, not able to detect the water level in the drum.

Is it indicating an error?

I can investigate. No errors flagged up and water level seems appropriate judging by what I see.

 

[DIYspanner]

I've looked at the water level sensor, pipe and wire connections. All seem good. I took the sensor off and checked the contacts for n/o and n/c operation with the meter while blowing air in to the spout. Not sure which should open and close but the diaphragm works. Two wires with spade connection and a small plug with two thinner wires.

I did an empty run and the water filled to about an inch or so above the rotating drum.

For the fun of it, I unplugged and took the programmer out but all seemed good.

Any suggestions for further investigation welcome. Bosch model WAE28162GB/09

 

[Harry Bloomfield]

I did an empty run and the water filled to about an inch or so above the rotating drum.

For the fun of it, I unplugged and took the programmer out but all seemed good.

Any suggestions for further investigation welcome. Bosch model WAE28162GB/09

All seemed to be OK, from the tests you've done. Next step would be to check the operation of the relay, or triac, which powers the heater.

 

[pto]

dry joint on the relay seen plenty

 

[DIYspanner]

There's no heater relay plugged into the module that I can see.

The two wires off the ntc sensor lug into the main module and appear to have good continuity.

The water level sensor has a two pin plug with the other end plugged into the module. There's no continuity between the sensor's contacts for either position of the sensor's diaphragm. The two spade contacts have continuity when pressure is applied to the spout.

 

[Harry Bloomfield]

There's not heater relay plugged into the module that I can see.

If there is no relay, then it must use a triac. Probably something like this...

TRIAC - Wikipedia

en.wikipedia.org

 

[pto]

its a relay on the main front pcb its a relay
its got a relay and always had a relay

 

[Harry Bloomfield]

its a relay on the main front pcb its a relay
its got a relay and always had a relay

Did you say it has a relay?

 

[DIYspanner]

I found the triac in question. Its fixed to a heat sink on the pcb.
Watching a few videos on YT, I tested it and appears to be faulty so I got the part number of it and ordered one.

Will post the results of fitting the new triac.

 

[Harry Bloomfield]

I found the triac in question. Its fixed to a heat sink on the pcb.
Watching a few videos on YT, I tested it and appears to be faulty so I got the part number of it and ordered one.

Did you say it's not a relay, after all

 

[DIYspanner]

So basically the triac acts as a relay?