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HmIP-FALMOT-C12, HmIP-WHS2 & central heating

Verfasst: 04.04.2023, 11:13
von mdobrovolskyy
Good morning,

I'm trying to finish my homematic underfloor heating installation, but so far only partial sucess unfortunately.

My setup is next, I have one FALMOT-C12 with 6 heads / valves connected via Access Point (and of course each room has own HmIP-STHD sensor). Also, I have connected WHS2 to Siemens RVP200 to control pump via external switch connection. That setup should work like that :

Default state of OUT2 on WHS2 is NC, i.e. it's closed and Siemens RVP200 works on "normal" mode (because it's closed), i.e. it runs a pump, mix hot water from central pipe, etc - i.e. normal behavior

Once rooms are heated enough WHS2 should open circuit and that should move RVP200 into standby mode.

HmIP-STHD works fine with combination with FALMOT-C12, I can see that valves are open and closed (partially) when it's required, issue is WHS2. I have tested and find out that WHS2 needs difference of 0.5 grad Celsius in order to change OUT state, i.e. I need to have 21.5 grad (21 is requested for example) in order for WHS2 to open circuit.

Did somebody faced same issue? Any solution for that with AccessPoint based installation or CCU3 will be a solution only?

P.S. Did you guys ever tried to contact Homematic Support? I had 2 technical (one is about this issue) cases and all I got is "Planning and setup must be carried out by a qualified person, as local conditions, manufacturer specifications and standards as well as the infrastructure used must be taken into account.". I have selected this product based on some criteria's and availability of support was one of that. Is it like that always with them?

Thank you

Re: HmIP-FALMOT-C12, HmIP-WHS2 & central heating

Verfasst: 10.05.2023, 14:48
von t.mezykowski
Hi, I'm was thinking about similar setup for underfloor heating and doing some research because looks like official documentation is poor.
From what I know room thermostats can have their own hysteresis, usually 0.5*C for this kind of applications. So it's more like feature not bug.
In your setup FALMOT is responding to room thermostats demand. Is my understanding correct that as long as there is heat demand at least from one thermostat FALMOT will set particular output of WHS2 to ON state which could be connected to circulating pump? IS this WHS2 output connected to particular thermostat or it doesn't really matter which on has heat demand? Can this be extended to 2 FALMOT's (this is my case) one upstairs one downstairs. I would expect that WHS2 reads the status of each FALMOT heat demand and set ON on one of its outputs.
Is my understanding correct?