www.freedomhp.co.uk
©G Hendra Nov 18
10
The Operation of the HW cylinder
The operation of the HW cylinder is as follows:
Factory set, if the hot water set temperature is set to + 48C the unit will start heating the
cylinder when the temperature drops 5C below set point (43C), it will heat the cylinder until 2
degrees above set point or 50C.
The dead band can be adjusted using settings
3022
(2) to adjust how far over the set point it
heats too and
3023
(5) how many degrees the tank temp has to fall before hot water mode
starts.
There is a minimum operating time in HW mode of 5 mins, this can be adjusted in setting
3024.
If the HW is switch on and then off again it will operate for this minimum period in HW.
The maximum operating time in HW mode is adjusted using setting
3025
. For example, if HW
mode starts and setting
3025
is set to 30 minutes, the hot water mode will end IF either the 30
mins is reached or the set point is reached, whichever happens first.
Normally we set the max time to 60 mins for a 300L cylinder. But beware if we are heating the
cylinder we can’t heat the house at the same time.
If the cylinder has completed a HW cycle if cannot return to HW mode for a preset time
period, it’s measured in ½ hour segments,
and set in
3026
. The factory setting is 3 = 90
mins. So the operation is like this:
Tank drops to 43C, HW mode starts, tank
temperature raises but after 30 mins it has
not reached set point, HW ends and heating
resumes. The tank is still not warm enough
but the unit will heat the house for 90 mins
then return to the tank for 30 mins and so
on.
None of the timers are used if there is no Heating demand, in this case the unit can heat the
tank 24 hours a day.