Technical data
68
CTC EcoZenith i250 
Installation
The flexibility in the CTCEcoHeat and CTCEcoZenith i250 is optimised 
because the products contain functionality for five basic systems. These are:
Solar "system 1"
Solar "system 2"
Solar "system 3"
Diff thermostat function
Pool
Solar also offers the facility to recharge the drill hole or collect energy for an 
extra tank, with or without a solar coil.
*The differential thermostat function can be connected to an existing PCB in 
the CTCEcoHeat400/CTCEcoZenithi250, while Solar systems 1, 2, 3 and 
Pool require the product to be supplemented with the CTCSolar Control/
Expansion Card accessory.
Explanations of system options
Solar system 1
Charge from solar panels only to the H-tank (H) in the CTCEcoHeat400 or 
CTCEcoZenithi250
Solar system 2
Charge from solar panels only to the EcoTank buffer tank + 
CTCEcoHeat400/CTCEcoZenithi250.
Solar system 3
Charge from solar panels either to X-Volume or CTCEcoHeat 400/
EcoZenithi250.
Using a diverting valve, the charge is prioritised 
either to the H-tank in the EcoHeat/EcoZenithi250 
or to the external X-volume
Diff thermostat function
The differential thermostat function is used if you 
want to charge your EcoHeat/EcoZenith from an 
existing wood-fired boiler, a water-jacketed stove or 
another cheap heat source.
The function compares the temperature in the 
EcoHeat/EcoZenith and the external heat source. 
Charging starts when it is warmer in the external 
heat source.
NB: For certain heat sources, e.g. solid fuel boilers, 
automatic chargers are recommended, among other 
things to counteract condensation in the fire box.
System options, Energyfl ex
Schematic diagram only The installer adds expansion vessels, safety valves, etc., and sizes the system.
G98
G99
B5
G46
B6
B46
Y11
H-tank 05
Schematic diagram for differential thermostat function










