Glow.Worm Micron 50FF Temp Problems

[Steve3948]

Hi,
I have a problem with a Micron 50FF, where the temperature is set to Max, I have a pipe stat on the flow and return above the boiler, which is only getting to 50 degrees C, the boiler then cuts off and temp drops back to 30 degrees C before coming back on.
The return is always about 5 degrees below the flow temp.

The rads get hot but then only warm.
I replaced the PCB last year, due to a working/not working issue, that cured the problem, but now rads are just not getting hot enough.

Would I be correct in thinking this is a thermistor problem.

 

[mickyg]

remove thermistor, check with multimeter, should read 10-12kohms at room temp.

 

[Agile]

He means a pipe thermometer ( not a pipe stat! ).

They can be quite inaccurate!

50° C is somewhat too hot to hold, about five seconds before you have to take your hands off. ( Except Chris R who has special hands! )

Tony

 

[Steve3948]

He means a pipe thermometer ( not a pipe stat! ).

They can be quite inaccurate!

50° C is somewhat too hot to hold, about five seconds before you have to take your hands off. ( Except Chris R who has special hands! )

Tony

You are correct, I did mean Thermometer, but we Electricians call eveything Stats

Yes when the boiler hits 50° C the pipe is to hot to hold for more than a few seconds, but then it drops to 30° before cutting in again.
By this time the rads are only warm and the rooms are getting cold again.

What temperature should the boiler reach if the boiler is set to Max, and when should it cut back in on temperature drop.

I will check the Thermistor, but I will get a new one anyway, as I read a previous post where it was advised if the PCB was changed it made sense to change the Thermistor at the same time.

Thanks for the help, I am ok on the controls but not the functions of the boiler.

 

[Agile]

About 83 C on max. Cuts back in about 4-6 C lower but possibly after an anticycling delay of 3-4 minutes.

Measure the resistance of the sensor as a first step at room temp and at 50 C when it should have fallen to about half of the resistance.

Tony