Remeha Avanta OTC+RT control

[Silviu B.]

Hello,

I have recently fitted an outside temperature sensor to my Remeha Avanta 28c boiler.
I fitted the sensor my self and wired it to connectors 1 and 2 on the X9 terminal block as per the information provided I the manual paragraph 2.7.5.

After fitting the outside sensor I have changed the control setting on the ISense from RTC to OTC+RT.

After doing this change I have noticed that the boiler is still running (the small flame was displayed on ISense next to the radiator) even when the insides temperature is above the set point. The boiler kept going even when I reduced the inside required temperature.


I can see the outside temperature displayed on the ISense. I have also checked the outside temperature on the boiler and the outside temperatures is displayed there as well.

I have not changed the default heating curve settings.
I have played with the RT effect and changed it from 5 down to 1. This didn’t have any effect on the control.

Is there anything else I need to do to get it to work?

 

[D_Hailsham]

You need to set the correct heating curve, which will depend on the system and the environment. The iSense manual gives instructions.

 

[Silviu B.]

Hi D_Hailsham,

Thank you for your response.

I have changed the heating curved based on an example for heating by radiators with very good insulation I found in the attached pdf ISense manual. This pdf manual gives a bit more information then the printed copy I have.

It seems to working now.
I though I would have to make a lot more changes and that it would take a lot more attempts.
I’ll keep an eye on it to see how it goes.

Thank you very much for your help!

 

[D_Hailsham]

It's good to know you have sorted your problem. It also saves me having to upload a copy of the iSense manual.

Have you checked the room and outside temperatures using a different thermometer? If there is a discrepancy, this can be corrected using Calibration (4.3.6).

 

[Silviu B.]

Hi,

Thank you for your calibration suggestion. I will check with another thermometer and adjust if required.

I had the day temperature set at 22 deg C. Today it was warmer than yesterday and the room didn’t get warmed up to 22, it stayed at 21. I don’t necessarily mind as the outside temperature was around 10.

If the room temperature din’t get to set point of 22 deg C does this mean that heaving curve is not set right and that I should change it?

I could leave with it like this if the room temperature goes to 22 deg C when the outside temperature is closer to 0 deg C.

 

[D_Hailsham]

You are correct in thinking that, if the room does not reach the required temperature, the heat curve needs adjusting. I would try the "good insulation" settings first as your house may not be as well insulated as you think. If that has the opposite effect, i.e house gets hotter than you want, drop the climate flow temperature 2 degrees. It is a case of tuning the curve to your system/house.

Unlike "normal" thermostats, an OT stat with WC does not turn off when the room temperature reaches the set temperature. All it does is control the flow temperature according to the heating curve. If the flow temperature is not sufficient to reach the desired room temperature, all you can do is adjust the curve to give a higher flow temperature. It's a case of try it and see.

 

[Silviu B.]

Thanks for the detailed response.
It is clear know. I will play with the heating curve to adjust it to my house and heating system design.

Thank you very much for your help.

 

[D_Hailsham]

I will play with the heating curve to adjust it to my house and heating system design.

Make sure you only change one thing at a time, e.g climate outside temperature or climate flowtemp, not both at the same time. Then monitor its effect

Climate outside may be a good place to start as it is currently -10C, which may be suitable for Europe but is rather low for the UK, which only got down to about -5C recently. So change climate outside to -5C without changing anything else.

 

[Silviu B.]

D_Hailsham,

Thank you very much for the taking the time to provide me with this very valuable information.
It has helped me to understand how the system works with OTC and RT.

I will make one change at a time an monitor the impact.