Assistance in English please

[pedrocalima@gmail.com]

Hi all,

I have been google translating this forum for the last months and it has been a great source of knowledge.

Two years ago I have moved to a rintamamiestalo in Helsinki and have just now (last week) changed from Kaukolämpo to määlämpo with a bosch 7800i 16Kw.

The radiators and all pipes on the house are new (2 years old) and there is floor heating on the basement and shower/sauna area. The floor heating is done with a branch from the main heating circuit that goes though a thermostat and pump that lowers the water temperature and circulate under the floor.

With kaukolämpo I could set a minimum temperature for the heating circuit of around 30 Celsius so the floor heating would always be working. Now with määlämpo, during summer the radiators are not needed but as we want to keep the floor warm on the basement I tried keeping the heating on on the BOSCH and I think the machine is short cycling a bit too much. Last I saw it had turned on and off 14 times in one day.

I don't have a buffer tank for the heating circuit and I'm thinking that it would help with the short cycling.

What do you guys think?

Cheers
Pedro

[pedrocalima@gmail.com]

I think I found the answer on a blog post from Bosch:
https://blog.bosch-climate.fi/viisi-tarkeaa-vinkkia-maalampojarjestelman-hankintaan

[Timo Karhu]

Hi Pedro,

not really an answer to you, but as I live in rintamamiestalo as well, and possibly have the sauna renovation ahead in near future, I have been thinking wouldn't it be possible to put electrical heating along with heating pipes in the concrete. Idea is that as electrical heating is so cheap to install, it could be then used during the warm months.

With such a small load your 16kW pump would definitively run in short intervals.

BR,
Timo

[pedrocalima@gmail.com]

Hi Timo,

I think that can be done, maybe passing the pipe and the heating wire following the same route under the floor.
I have no idea how much energy it goes to heat my basement floor. Without heating it's pretty cold and I was not the one doing the whole slab work so don't know what kind of insulation there is under the concrete. There is a big chance I'm loosing money heating the ground under my house.

I'm really interested to see how all this will work during winter. The house has used 36000 Kwh in 2021, lets see how this 16Kw pump will work.
I will count the number of starts for the next days and decide about the buffer tank. I think there is no harm in putting one into the systems but it costs money and takes space on the garage.

If you are renovating your basement floor I would focus on the thermal insulation, humidity management and radon mitigation. If you are doing only the surface change them maybe you can only do the heating.

Cheers.

[jmaja]

How long did it run each time? Do you have some logging where you can see this? At least you can see the compressor running hours sepsrately for heating and warm water from the menus.

If each run is 10 min or more, I wouldn't worry about it. How much area do you have with heating floor heating in summer?

Is the heat curve set properly for the summer so that  the output is cold enough.

Concrete has a lot of heat capacity due to its weight. You would need a huge buffer to change the run times considerably unless you have just a very little heated area in the summer.

[Timo Karhu]

I think there is no harm in putting one into the systems but it costs money and takes space on the garage.

My experience with 100l buffer tank and radiators, I would support what jmaja said. Save your money & space, perhaps?