SAJ + CTC

What Zerofy can do with SAJ and CTC

In practice

• Hot water is the simplest heat store: Autopilot can use the hot-water boost of your CTC heat pump to heat water in hours with surplus.
• A heat pump draws roughly 1–3 kW while running, which a typical SAJ home system (3–10 kW) can cover on sunny days.
• Zerofy gets new SAJ data every 5 minutes. Heat pumps shouldn’t switch often, so set a minimum runtime in Autopilot.
• Zerofy also shows your SAJ battery, so you can see whether surplus goes into the battery or into the heat pump.
• If you use CTC’s own spot-price control in myUplink, its “Blocking” at high prices can lower the hot-water setpoint; check that the CTC price limits and Zerofy’s Smart mode don’t pull in opposite directions.

What SAJ and CTC offer on their own

SAJ: The SAJ eManager has two dry-contact (DO) outputs for a heat pump, switched by tasks you set up in the app. SAJ says Elekeeper supports heat pumps and water heaters but doesn’t list compatible models.

CTC: CTC controllers have SmartGrid inputs (terminals K22–K25, a SmartControl wireless accessory or BMS): when an inverter or energy manager closes both contacts (“SmartGrid Overcapacity”), the controller raises the room/flow setpoint by 1–5 °C and the hot-water setpoint by up to 30 °C. Through myUplink, CTC can also download spot prices and switch between “Low price” and “Blocking” on its own.

Zerofy connects the two: it reads SAJ production and controls your CTC heat pump to match, together with your other devices in one app, with dynamic tariffs and forecast-based Smart mode.

Setting up SAJ and CTC in Zerofy

1. Connect SAJ

Zerofy reads your plant from the SAJ cloud: you add Zerofy as a developer in the Elekeeper app and then enter your Plant ID in Zerofy.

1. In the Elekeeper app, tap ••• and open Plant Management.
2. Under Developer/Partner, paste the Developer ID shown in Zerofy and confirm access.
3. Copy your Plant ID from Plant Management and paste it into Zerofy.

Good to know: How fresh the data is depends on how often the SAJ cloud updates. For the battery, Zerofy supports forced charging but not switching the battery mode.

Step-by-step guide for SAJ

2. Connect CTC

Zerofy reaches CTC heat pumps through the myUplink cloud, the same connector used for NIBE, with your myUplink login; Autopilot controls the hot-water boost.

1. Connect the heat pump to the internet and register it in the myUplink app.
2. Make sure your myUplink account has the subscription needed for remote control.
3. In Zerofy, connect myUplink and log in with your myUplink credentials.
4. Enable Autopilot (Solar or Smart mode) for the hot-water tank.

Good to know: Zerofy steers only the hot-water boost on CTC units, not room or flow temperature.

3. Turn on Autopilot

In Zerofy, open your CTC heat pump, turn on Autopilot and choose Solar – or Smart to also use dynamic tariffs and forecasts. Set the priority, activation threshold and minimum runtime.

Dynamic tariffs

Zerofy can also run your CTC heat pump on dynamic electricity prices (EPEX Spot or Nord Pool, e.g. Tibber or aWATTar) or on a fixed time-of-use tariff. Smart mode combines those prices with forecasts of your household consumption and your SAJ solar production.

Learn more about Smart Mode

About SAJ and CTC

SAJ – SAJ (Guangzhou Sanjing Electric) is an inverter maker from Guangzhou, China. Homes usually have the H2 hybrid inverter with B2 battery or the HS2, HS3 or AS2 all-in-one storage systems; the eManager unit and the Caro wallbox tie them together. Monitoring app: Elekeeper.

CTC – CTC is a Swedish heat pump maker from Ljungby. Its air-to-water, ground-source and exhaust-air heat pumps and EcoZenith indoor modules are controlled remotely through the myUplink app. Products: CTC EcoAir, CTC GS/GSi 600, CTC EcoZenith i255/i360/i555 Pro, CTC EcoPart i600M, CTC EcoVent i360F, CTC EcoLogic L/M.

Manufacturer information last checked: October 2026.

All devices that work with SAJ