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Understanding Remeha Recom Data

PostPosted: Thu Jan 01, 2015 12:49 pm
by D_Hailsham
I have been looking at the Recom data from a Remeha Avanta boiler. Most of the items recorded are obvious, but there are some I do not understand.

Can anyone explain what these items are:

1. Internal Setpoint (°C)
2. Boiler Control Temperature (°C)
3. Available Power (%)
4. Actual Power (%)
5. Required Output (%) (This never changes from 0)

Many thanks

Re: Understanding Remeha Recom Data

PostPosted: Sat Mar 07, 2015 10:14 pm
by nickhend86
1. Is the calculated internal setpoint by the boiler controller. Depending on how you control the boiler, for example with an outside temperature sensor, by 20°C outside, the setpoint of the boiler is probably calculated to be 20°C.
2. I'm not sure wich this one is.
3. Available power is the maximum power that the system can supply. When you have an installation with multiple boilers and one boiler is down, the controller can tell how much of the power is still available.
4. Actual power is what the boiler/system is currently providing.
5. The required output is what the controller has calculated, depending on how many boilers in the system. If you have 4 boilers, each 65 kW, and the controller has a calculated setpoint of 25°C, the controller won't need the power of all 4 boilers. So it tells how much power it needs to reach 25°C water.

I use the Recom software with boilers from 21 to 600kW and with systems with multiple boilers, so most of these items are for use with the Remeha MC or MC5 controller.

Re: Understanding Remeha Recom Data

PostPosted: Mon Mar 09, 2015 4:57 pm
by D_Hailsham
Thanks very much for your reply. I was beginning to give up hope after nearly 700 views without any reply.

The Recom data I am looking at was taken from a Remeha Avanta 24S system boiler mainly when running to heat a hot water cylinder.

The Internal Setpoint (ISP) is 73C. This appears to be 58C (required HW temperature) plus 15C, which is parameter 31 (set point augmentation). The Boiler Control Temperature (BCT)is approx 30C. Obviously controlling the boiler to 30C will never result in the HW cylinder heating up to 58C temperature. So is this the Opentherm Control Setpoint (Opentherm ID No 1)?

There is some data when the boiler was running for CH. When this starts the ISP instantly rises from 7C to 90C; but the BC stays at 30C. A few minutes later the ISP drops to 45C and the BCT doesn't change. When the boiler turns off the ISP drops to 7C but the BCT still stays at about 30C.

If you set the Recom Language to Dutch, the BCT is described as "Automaat temp", which Google Translate tells me is "Automatic Temperature".

The Power info is easier to understand. I have worked out that 0% means that the boiler i running at minimum modulation and 100% is max modulation, though I don't understand how the Actual power can be greater than the Available power.

Luckily I only have one boiler to play with, so I would expect the Required Output to be 100%.

It's a pity Remeha don't publish info relating their parameters and data to the Opentherm IDs.

Re: Understanding Remeha Recom Data

PostPosted: Fri Mar 13, 2015 4:13 pm
by nickhend86
The name Opentherm suggests that this protocol is open for use, but unfortunately, this isn't. The manufacters of boilers keep their parameters for themselves, but I've been in contact with Remeha developers and they don't really care if people know the parameters. I was messing around with a c-mix controller from Remeha when it just came out, and I had a lot of questions about this strange device, so I got connected with the developer. Maybe I should call them again to ask about the parameter numbers...(I'm an engineer, who works exclusively with Remeha. )

The boiler control temperature is the temperature inside of your boiler, around the internal controller/burnercontroller. I guess it functions as a safety for your burner controller. I don't know if it's connected or used in an Avanta, but when a parameter constantly says 30C, it's most likely not connected.

When there is demand for DHW, the internal setpoint will be, in your case, 58C. DHW overrules central heating.

I hope I could help you with your questions.