Yet another Buderus GB142 Question

GB142

For those of you who have not seen any of my earlier posts, I am coming up on year 15 with my GB142, which seems to be longer than most.

One question I have regarding my unit which I am hoping can be answered pertains to my boiler communicating with my 70 Gallon Boilermate Indirect Hot water tank. I am running well water... which is not that great. About 8 years ago, my GB142 kept cycling on and off during the middle of the winter attempting to heat my domestic hot water. Needless to say, when it was doing that, it was prioritizing over the indirect hot water for the home heat and the house would get cool.

A service tech suggested that the Buderus was not getting a proper water temperature reading from Boilermate and thought it was due to "dirty or fouled" heating elements "inside" my Boilermate.

So I drained the Boilermate and inspected the inside only to find the aluminum fins looked like they had orange fuzz on them from the well water iron deposits. I ended up flushing the system with a mixture of 3 gallons of white vinegar combined with fresh water in the tank. Then I turned Buderus on to heat up the water for the removal of the deposits.

Afterward, it seemed to work better and my Buderus stopped the constant "on/off" cycling to heat the Boilermate. Coincidence?

I have not done this 2 more times... most recently 6 weeks ago the aluminum fins in the Boilermate were again very dirty.

However, looking back at this, I believe my Boilermate has a temperature sensor in the bottom of the unit in a self-contained space. So, I have not idea why cleaning the inside of the Boilermate would affect the Buderus from being able to read a proper temperature.

Sorry for all the babbling, but the crux of my question pertains to Buderus's current operating characteristics.

When it switches to heating the domestic hot water, it will cycle on and move up to an operating temp right up to 199, then give an 0Y code, then as the temp starts to come down, the Buderus will turn off as the temp drops to around mid 170s, then the boiler will cycle back on and repeat this process. Today it actually did this for about 5-10 minutes until it seemed that the Boilermate reached ideal temperature then shut down completely.

Is this normal? In the past, don't recall the cycling on/off. I only remember it cycling on until the ideal temp has been reached then it would cycle off... so I think.

In the meantime, we have ordered a Boilermate temperature sensor to see if a new one may eliminate all the cycling.

Big Ed_4

Hit the little wrench on the BC10 controller the second code if any would direct us to which temperature is tripping . I would check the temperature between the boiler and return pipe to the indirect . There should be 20* or better difference .

Now is the indirect piped straight though the boiler or piped as on of the heating zones ?

If though the boiler what model circulator is being used ?

Second error code ?

Temperperture diff ?

How is it piped ?

What model circulator ?