Temperature reading is too low  

RE: Temperature reading is too low

I don't know why, but the solution was that the heating element wasn't adequately tightened into the clamp in the block.

RE: Temperature reading is too low

i must also use too high temps ...

what you mean with "heating element"? What did you do to fix ? maybe a photo can help?

do you print after that fix with "normal" temps, i.e. for PLA ?

RE: Temperature reading is too low

For me, I replaced the heater cartridge and the hotend thermistor with some spare aftermarket ones. Now temperature reading matches +/- 0.5 °C the real measured temps with a FLIR thermal camera.

I think there was something broken in my cable, also the sensor was reading much lower temps since beginning. Don't wanted to print with 15°C offset, so I replaced.

RE: Temperature reading is too low

I too seem to be having a similar problem. 

I received my printer in November and a little bit of figuring out how it worked.  I discovered I needed to set the temperature to 213C to print PLA.  But once I discovered this, I had no trouble printing PLA and was getting very nice prints out.  However on the 3rd of Jan I could not get the printer to print and the previous day a successful 12-hour print that I finished about 10:30pm.  I do not seem to be able to print anything I get a very bad first layer and eventually clicking when trying to extrude filament.  Initially I thought the hot-end was block however this is not the case.  I have noticed that I cannot push filament through the hot-end until the temperate is set to 255C this is 40C higher than expected.  I see on the forums that there are others having the same issues but this seems more extreme.  

I am unable to complete the first layer calibration and am quite stuck at to what to try next.

RE: Temperature reading is too low

this sounds as if you may have a blockage and the filament needs to be more fluid than normal, in order to get out of the nozzle.
If you have an accupuncture needle try pushing it into the nozzle from below to clear a blockage... 
Or you can try a cold pull 
https://help.prusa3d.com/en/article/cold-pull_2075
maybe a couple of cold pulls. 

regards Joan

RE: Temperature reading is too low

@joantabb

Done all that, cold pull... I discovered that if I increase the temperature on the hot-end to 255C on the screen, then I can push filament through and even successively 3d print an object in PLA.  It seems that something drastic has happened to the temperature sensor on the hot-end.  I have no way to verify the temperature sensor is reading correctly or not.

RE: Temperature reading is too low

@rodb

Another possibility: Either the ambient temperature is very low or the thermistor or heating cartridge is damaged or have a bad electrical contact.

Maybe you check the thermistor and the heating cartridge:

https://help.prusa3d.com/en/article/multimeter-usage_2117

RE: Temperature reading is too low

@karl-herbert and all,

Turns out that @joantabb was right, for me the thermistor was a red herring.  After talking to support, they gave me the specs for the thermistor and I was able to verify it was with-in specification and there are none that I can find loose connections on the thermistor.  I then performed a cold pull and re-tension of the ptfe tube.  This worked for me.

RE: Temperature reading is too low

@rodb

That is great news.  One thing is certain, this will not be the only time you will chase your tail when doing a repair.