FAQ
TL;DR: 150 m² AMC25 users report heating + DHW for ~3 000 PLN/season [Elektroda, Panderecki, post #19015313]; “Weather control is very convenient” [Elektroda, Wojewoda82, post #18100865] Set curve 1.3-1.5, cap flow ≤ 65 °C, and adjust frost, sensor influence, or manual demand as needed.
Why it matters: Correct parameter choices cut gas use, prevent scalding, and stop boiler cycling.
Quick Facts
• Minimum output: AMC25 – 5.5 kW at 50/30 °C; AMC15 – 3.4 kW [Elektroda, Wojewoda82, post #18100865]
• Recommended CH flow cap: 60–65 °C for aluminium or steel radiators [Elektroda, Zbigniew Rusek, #18100234].
• Typical radiator curve slope: 1.3–1.5 gives 45 °C flow at 0 °C outside [Elektroda, Panderecki, post #19015313]
• Estimated annual gas: 1 600 m³ ≈ 3 150 PLN for 200 m² house [Elektroda, Wojewoda82, post #18102342]
• Frost-protection default: 6 °C flow below user set outdoor limit (factory –3 °C) [Elektroda, Panderecki, post #19225225]
How does the external weather sensor control room temperature?
The sensor feeds outdoor temperature to the boiler; the heating curve then decides flow temperature. Room comfort is fine-tuned with radiator thermostats, not the boiler menu [Elektroda, Panderecki, post #18099241]
What heating-curve slope should I start with for radiators?
Set 1.3 in early autumn, raise to 1.5 in normal winter, and 1.6 in severe frost. A 1.4 slope gives ≈45 °C flow at 0 °C outside [Elektroda, Panderecki, post #19015313]
What is the safe maximum flow temperature?
Keep CH supply ≤65 °C; above 75 °C radiators can cause burns and kill condensing efficiency [Elektroda, Zbigniew Rusek, #18100234].
CIRCA vs. CIRCA1 – which should I use?
CIRCA uses the front CU-GH08 board; CIRCA1 is on the side SCB-10 board. With one direct circuit, pick the board actually wired and disable the other to avoid “frost protection 6 °C” messages [Elektroda, Dobroslaw, post #18115940]
How do I set a constant flow temperature without any thermostats?
- Menu › Burner.
- Set AP002 = 1 (manual demand).
- Set AP026 to desired flow, e.g., 40 °C. The boiler will modulate around this value continuously [Elektroda, Wnowak, post #19661652]
Can I override weather control temporarily?
Yes. Open Burner › Manual heat demand, set 40 °C (or needed value), then disable when comfort is reached. This supersedes all zone settings [Elektroda, Panderecki, post #19071966]
How does frost protection work and how do I adjust it?
Heating stops above the user threshold (factory –3 °C). Below it, the boiler forces ≈60 °C flow to protect pipes. Lower the threshold to –10 °C to avoid needless high flow in mild cold [Elektroda, Panderecki, post #19225225]
What does “room sensor influence” mean?
It is the weight (0–10) given to room feedback versus weather data. Value 5 means weather still dominates; values >5 put more weight on the indoor sensor [Elektroda, DJTrueBeliever, post #20735443]
Gas use seems high—160 m³ in 30 days for 200 m². Normal?
That equals 1 900 kWh or 10 kWh/m²-month. With only 10 cm EPS insulation, it is typical. Better insulation or lowering curve by 0.1 can save ~5 % fuel [Elektroda, Piotrkafka, post #19672745]
What happens if my boiler is oversized?
An AMC25 in a 100 m² low-loss home will idle at minimum 5.5 kW, causing on-off cycling. Cycling can cut seasonal efficiency by 10-15 % and shorten fan life [Elektroda, Wojewoda82, post #18100865]
How to force heating when weather control keeps the boiler off?
- Menu › Burner › Manual heat demand.
- Enter desired flow (e.g., 35 °C).
- Confirm; boiler fires regardless of outdoor temp. Disable manual mode afterwards to return to automatic control [Elektroda, Panderecki, post #18197627]
What does AP075 Neutral-band hysteresis do?
It sets the gap between heating off and possible cooling on mixed systems: heating stops when daily average >AP073, restarts only when average <AP073 + AP075. In heating-only systems the value is cosmetic [Elektroda, DJTrueBeliever, post #20767908]
Can AMC handle radiators and underfloor heating together?
Yes. Connect radiators to CIRCA1 and underfloor loops to CIRCB1/CIRCC1 on SCB-10, then assign separate curves (e.g., 0.4 for UFH, 1.4 for rads). A three-way mixer downstream of SCB-10 outputs keeps low-temp loops safe [Elektroda, Wnowak, post #19071190]
