Time Clock Set-Up/ Patterns - Mitsubishi Electric Ecodan PUHZ-W50VHA-BS Homeowner's Manual

Time clock pattern set-up
The Flow Temperature Controller time clock patterns must be set to accommo-
date a hot water priority system. For example: The hot water heat up cycle
should have an ON/OFF time approximately 1.5 hours apart (dependent on the
cylinder capacity), this time should be outside the time period where space heat-
ing is required as it will not be available while hot water is taking place. Hot water
heating should be set to occur during the night periods where space heating is
not required and cheap electricity tariffs are available.
Time clock patterns
The Ecodan® system incorporates hot water demand priority this means that if
there is a demand for both modes hot water will always occur before space heat-
ing.
Due to this the periods at which hot water and space heating are programmed to
operate are extremely important. The hot water heat up times should be pro-
grammed to occur during periods when space heating is not required, this is usu-
ally the early hours of the morning and early afternoon. Using the hot water re-
covery time period taken during the commissioning stage ON/OFF time must be
programmed by the commissioning engineer into the 2 channel timeclock, for
example if the cylinder took 60 minutes to reach 55°C then the hotwater ON
time should be for example 3.00am and the OFF should be 4.15am leaving 15
minutes additional buffer. After this time space heating will be allowed to operate
as required.
Important Note- If the hot water demand is left ON continuous operation rather
than being timeclocked to switch OFF then the homeowner may experience un-
necessary high running costs.
Economical Time Clock Patterns & Flow Temperatures
To gain the full benefits from the Ecodan® system the target flow temperatures
and timeclock patterns need to be configured to suit the actual property de-
mands. The most economical way of operating the system is to have it running at
the lowest flow temperature possible to suit the properties thermal losses.
To do this the heating demand from the time clock should be left constantly op-
erational and the flow temperatures should be reduced to a point where the
property is maintained at the design temperature (usually 21°C) without being
switched ON and OFF from the room thermostat or TRV's. 7-day timer clocks
with night set-back can also offer good system efficiencies.
Important note- If the heating demand is left on continuous operation and the
target flow temperatures are not reduced to their lowest possible then the
homeowner may experience unnecessarily high running costs.
Example timeclock patterns
Below is an example of a standard timeclock pattern please note this is for refer-
ence only as the inputted times should suit the site environment and the home-
owner preferences.
Heating mode – continuous operation with reduced flow temperatures.
Hotwater mode :
3.00am ON
2.00pm ON
4.45am OFF
3.45pm OFF
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