De Dietrich MCR II / 24 Stove: E2 Error in Heating Mode & Restart Solution - Maintenance Advice

Question

Hello. I have question for you. I have had a De Dietrich MCR II stove for 2 years. The furnace was serviced in June this year and it was ok. On Friday I started the heating and there was an E2 error. After restart it started and it was ok for a while. But after a long time of downtime (when...

piracik · Answer

Return temperature higher than flow temperature.
Do you have a second boiler, e.g. a coal boiler or a fireplace with a jacket?
Check that the valves are open.
Check that at least 3 or 4 radiators are set to at least 3.
You can feel if the return pipe is actually warmer than the supply pipe.

If all of the above is OK, then you can choose:
- pump failure
- defective return or supply sensor
- supply sensor not installed (e.g. after inspection or repair)
- air in the boiler

exeter85 · Answer

Error E2 can mean several things: low system pressure problem with boiler sensors circulation problem (pump) dirty filter what

Danper2 · Answer

Thank you for the hints. Due to the fact that yesterday the problem was repeated again, I called the furnace specialist. The strangest thing about the whole situation is that once it fires up, it then works flawlessly until a long downtime. I'll let the technician know where the problem was.

exeter85 · Answer

I bet that the filter in the left hydro block may be dirty

Danper2 · Answer

Suggestions by pirate and exeter85 were confirmed. On October 21, a service technician visited me and after replacing one temperature sensor (in the spare parts catalog item No. 2013 No. S58733) it works ok.

Regards and thanks for your help

Anonymous · Answer

Hello,
I have a similar problem but from the beginning:
I have been using the boiler as in the subject for five years, but most of the season I burn wood or coal in 9kW Stąporków - gas on weekends and when I leave for a few days.
Over the years everything worked perfectly and there were no disturbances even if I turned on the gas boiler with a hot coal.
I used an Ariston heater for HUW.
The problem appeared when I eliminated Ariston and connected a horizontal 120l DHW tank with a water jacket - placed about 1.20 cm below the lower De Dietrich level.
Initially, after the installation in October, everything worked perfectly, but then I did not heat the central heating from this boiler, I only used wood.
The problem appeared after switching the heating to a gas boiler.
Initially, I tried to vent the boiler, but it did not bring any improvement.
I noticed that the error occurs when the boiler switches from DHW heating to central heating.
Temperature settings are CO 40 degrees and HUW 50 degrees.
After the reset, the boiler starts and everything is OK until the next cycle ...
From this thread, I guess that the return temperature is higher than the supply temperature, but can it not be so when switching from DHW to CO?
Is it possible to introduce a delay in switching on central heating until the return temperature drops?

piracik · Answer

Is the solid fuel boiler operating at the time when the error occurs?

Anonymous · Answer

It doesn't work and is completely off... As I noticed, E2 occurs only when switching from DHW to CO ...

piracik · Answer

It is possible that the sensor has a gap in its characteristics, which is revealed at higher temperatures (DHW charging)

Anonymous · Answer

So it's time to call a service technician...
I have one more question, is it normal that when DHW heating is turned on, the first heating cycle (4) lasts about a minute, then 8, several dozen seconds and 1, 2, 4. Subsequent heating cycles last several seconds. And so on until the set temperature is reached...

piracik · Answer

This would indicate a low heat exchange capacity. Jacket/coil.

Anonymous · Answer

That's what I thought, but I wanted to make sure it wasn't supposed to be continuous heating.
I tried to look for the option to reduce the HUW heating power in the manual, but unfortunately I did not find such a possibility,,,
Thank you for your help.

dobroslaw · Answer

To reduce the power to DHW, change the parameter p 18, see how much p17 is set, i.e. heating, what you definitely have 37 (I don't know what model you have) p18 set from 46 to 40, you will go down with power, instructions can be found on the manufacturer's website. You may have too little pressure in the boiler, the filters may also be dead. In mcr 2 you have a hidden filter on the hot water supply, a plastic thing that is very difficult to remove, but if you don't have a hot water supply, it can be clogged, I usually throw it out because it disturbs more than it protects. It's best to call a service technician because you can only make things worse.

Anonymous · Answer

Five years ago, I set the P17 parameter, i.e. the maximum fan speed, to 20, i.e. 2000 rpm - boiler power 10kW.
I had the P18 parameter factory set to 46, i.e. 4600 rpm, power 24kW.
Today, immediately after reading the advice of my colleague, Dobrosław, I reduced P18 to 40, then to 30 until when I went down to 20, i.e. 2000 rpm, I got acceptable times - heating (on display 4): 1.5 minutes and pause (on display 8 ): 3.5 minutes
I repeated these measurements for the last four cycles before reaching the preset HUW temperature of 48 degrees (actual 50 degrees).
I measured the first heating cycle at P18 40 and it lasted about three minutes, but the next cycles were several seconds long. By reducing P18 successively to 20, it seems that I have achieved a more stable operation of the boiler without unnecessary start-up cycles. I guessed that the water jacket of the tank could not transmit the power of 24 kW, but I forgot how to reduce the boiler power for DHW.
I will see if this change also has any effect on turning off the boiler (error E2).
Thanks to my friends Piracik and Dobrosław for their help.

Anonymous · Answer

The problem with error E2 persists.
I called directly the service technician who performed the first start-up when I was only heating central heating without hot water, asking for a diagnosis and repair service, but to put it mildly, he sent me to the official headquarters and waiting for the assigned service technician to arrive ... 8-O

Before I use the official "duty path" I will ask one more question about the problem of this fault - "return temperature greater than supply temperature"
Well, this error and shutdown of the boiler occurred only once in two weeks.
Today I was able to force this situation:
When heating DHW and prior extortion of heat demand by central heating
I lowered the preset DHW temperature so that its heating would end.
The boiler started to heat the central heating and turned off after several seconds - E2.
At the time of failure t1 20 degrees t2 40 degrees,
The sensors seem to work well because when heating or CH or DHW the temperatures are appropriate, e.g. CO 40/35 and DHW 65/58 ...
And the question is: is it possible that the valve switching the heating water circuit does not close and initially the supply water flows partially from the hot water and not only from the central heating after switching to central heating? That would explain the "higher return temperature" for a while...
I will be very grateful for your help...

piracik · Answer

T1 - supply temperature T2 - return temperature Even the question of how it immediately cooled down by 20 * C to swim out cooler.

Anonymous · Answer

I am considering two possibilities: -actually a broken supply temperature sensor - but not electrically, just as if too much thermal inertia (but suddenly the heat capacity of its housing did not increase) ... - cooling the medium through the heat exchanger - but it's probably unrealistic. That's why I'm asking for details because I'm not from this industry as you can see... I will check if the power sensor adheres well to the power cable because it may have moved away and its reaction is too slow ... Because in a steady state, it certainly does not lie. Thanks for your help and I'll let you know the results

Anonymous · Answer

A success I don't like very much. The error does not return, but my actions can hardly be called a fix.
I swapped the supply and return temperature sensors.
I checked the temperatures t1 and t2 again immediately after turning on the central heating, immediately after turning off the hot water heating.
The temperatures t1 and t2 immediately dropped from 68 degrees C and 62 degrees C to 21 degrees C and 19 degrees C.
I checked the boiler several cycles and so far everything is OK.

Anonymous · Answer

The problem didn't happen again.
From the very beginning, I made a mistake thinking that the sensor in the brass connector next to the safety valve is the return temperature sensor and therefore its brass housing, after being heated by HUW, keeps the temperature of the T2 sensor high after switching to central heating for too long, and therefore E2 may throw it out. Meanwhile, this is a pressure sensor :oops:

(In the old MORA boiler it was screwed in - and it turned me on :wink:

)
I'm not closing the topic because I didn't start it, but once again thank you very much for all the hints and suggestions.

Skorpionek1111 · Answer

Piec de Dietrich Mcr II, Does anyone know what can cause a change in hot utility water temperature when the co is turned off (when turned on there is also this problem). Cold, warm, then hot, and so on. Changing the temperature doesn't help. And five errors do not show. E7 and E10 have popped up a few times recently but after restarting it doesn't show up anymore. First, it heats the water to the max and then turns off, and so on all the time.

De Dietrich MCR II / 24 Stove: E2 Error in Heating Mode & Restart Solution - Maintenance Advice

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