Dryer The washer works just fine, But the dryer starts up and give out some heat but after 20 secs it will shut off

i don't know. be careful with electricity. if possible, try running normal washer load along with your dryer but with [no heat] 'cold air only' to see if they will keep running.
if they run OK, consider shutting off both washer and dryer. shut off main electrical panel and change fuses for both washer and dryer. turn hydro on and run both again
with your normal settings. if they fail again please call for repairs. my dryer would not run and although everything looked and tested out OK, i had to replace a small 6x8"
electrical box having 2 only 30 amp screw in fuses.
then it ran OK.

Sounds like a possible motor over heating. The main motor has a heat safety built in that shuts it off if it gets too hot. It will restart once it cools off some. Over heating could be from excessive lint around the motor or even from a blocked vent pipe. All you can do is clean it well and check again. If it still shuts off the motor will need replaced.

f26 is code for motor so check motor ok

Sounds like your gas valve is fine, if it comes on at all, its good. A air flow restriction would cause a overheat condition and shut down the burner. Once it cools back down the burner would re-ignite and repeat the cycle. The sensor on the left of the burner is the flame sensor and the flame wouldn't come on at all if it was bad. You've already changed the coil kit so the valve is fine, disconnect the vent from the back of the dryer and see if the problem goes away. If the problem stays, I would suspect the thermostat. Good luck.

You have a broken belt.

It could be the door switch. If it vibrates a bit then the door switch senses it's open and shuts down. Give it a look

If you need further help, I’m available over the phone at https://www.6ya.com/expert/craig_3fa289bf857b1a3c

Hi, It sounds like the coils on top the gas valve are bad. If the ignitor glows but shuts off before a flame, the coils need changed.
I hope this helps. If I can assist you further, please let me know.

Thanks
Vic

Use or borrow a volt ohm meter and check for a grounded hot wire. You may also be exceeding the start up load on the 20 amp breaker. Test this theory (after you make sure that there are no ground faults) by starting the dryer in a "air fluff" mode without heat. If the dryer starts in the "no heat mode", switch the heat on - if you blow the breaker you know that the 20 amp breaker cannot handle it. Before you do any of the above - check your dryer manual for the service requirments. If you don't have the manual go to the mfg. web site and download it.

I have a Miele Novotronic T560C. The tumble drier is working fine except the air circulating is cold - it does not heat up at all. What could the possible reason for this and/or solution?

Start with resetting breaker dryer tumbles with 110 but needs 220 to turn on element. If still no heat might have a bad element.