77
Instructions for installation and use
TD & S substations
Danfoss District Energy
VI.GP.U2.02
DKDHR
6.
Enduser instructions, General
Instructions
Please read these instructions carefully before installing and commis-
sioning this substation. The manufacturer accepts no liability for loss
or damage resulting from failure to comply with these instructions
for use. Read and follow these instructions carefully to prevent the
risk of physical injury and/or damage to property. Exceeding the
recommended operating parameters appreciably increases the risk
of personal injury and/or damage to property.
Installation, commissioning and maintenance must be carried out
by qualified and authorised personnel (both plumbing and electri-
cal work).
Once the station has been installed and is operating, there is
nor-
mally
no need to alter the settings or other functions. The district
heating substation is very reliable and easy to operate.
If necessary, you can change the temperature settings as described
on page 8. For more detailed information about the substation,
see the sections concerning installation and commissioning.
Description
These instructions apply to two substation types (TD and S) – which
are both fitted with an instantaneous water heater and designed for
direct connection to the district heating supply.
TD substations are fitted with a differential pressure controller that
maintains a constant pressure in the radiators. The supply tempera-
ture to the radiators is always identical to the district heating supply
temperature. The room temperature is adjusted solely using the
radiator thermostats.
S substations are fitted with a differential pressure controller that
maintains a constant pressure in the heating circuit(s). The supply
temperature to the floor heating is regulated using the thermostat
in the substation. S substations are also fitted with a pump.
In rooms with floor heating, the temperature is regulated using the
floor heating thermostat for the room in question. In rooms with ra-
diators, the temperature is regulated using the radiator thermostats.
Alternatively, the heating circuits can be regulated using fully auto-
matic Danfoss ECL weather compensation equipment (not standard).
We recommend regular inspections of the substation - ideally in
connection with readings of the district heating meter.
Pay special attention to any leaks and an excessively high return
temperature in the district heating circuit (poor cooling of the district
heating water). Cooling – i.e. the difference between the supply and
return temperature of the district heating water – has a significant
effect on the overall energy economy. Therefore, it is important to
focus on the supply and return temperature in the heating system.
The difference should typically be 30–35°C in systems that operate
with radiators. In systems that feature floor heating, the difference
is typically 5–10°C. In these systems, it is important that the supply
temperature does not exceed 35°C.
Please note that a low district heating return temperature is directly
dependent on the return temperature from the heating/floor heating
circuit and the return temperature of the domestic hot water recircula-
tion (in systems with domestic hot water recirculation). It is therefore
important to focus on these return temperatures.
Warning! Hot surfaces
Parts of the substation may be very hot and can cause burn in-
juries. Be very careful when you are in the immediate vicinity of
the unit.
Warnings about high pressure and high temperature
The maximum supply temperature in the district heating net-
work can be up to 120°C and the operating pressure can be up
to 16 bar. This may result in a risk of scalding from touching the
substation and from outflow of the medium (water/steam). Ex-
ceeding the substation design data and operating parameters for
pressure and temperature carries an appreciable risk of personal
injury and/or damage to property.
Emergencies
In the event of fire, leaks or other hazards, immediately shut off
all sources of energy to the substation, if possible, and call for
appropriate assistance.
If the domestic hot water is discoloured or malodorous, shut off
all ball valves on the substation notify all users and call for profes-
sional assistance without delay.
Cooling from the water heater alone:
During tapping, the level of cooling will typically be 30–35°C. When
domestic hot water is not being tapped, it is completely normal for the
return temperature from the water heater to rise slightly. In this situa-
tion, the district heating meter will register very modest consumption
as the volume of water is very small.
On substations with recirculation, the calorie meter registers the heat
loss in the recirculation pipe.
Irregularities
When reading the meter, check all joints and connections for leaks.
If you identify any irregularities/leaks, contact your professional
provider for assistance.
Check the troubleshooting section before contacting your
professional provider.
