Auxiliary Heat - Danfoss DHP-A User Manual

Using a regular time interval, the water in the water heater is given extra
heat by the integrated auxiliary heater to prevent the build up of bacte-
ria (anti-legionella function). The factory set time interval is seven days
(can be adjusted). When the anti-legionella function is active the heat
pump produces hot water until the temperature for the start tempera-
ture sensor (5) has reached 60°C.
In the control system's TEMPERATURE menu, a number of measured and
calculated temperatures for the hot water and supply are displayed. The
current temperature for the peak temperature sensor (2) and the tem-
perature of the supply line during heating and hot water production are
displayed. The temperature of the supply line often exceeds the maxi-
mum permitted hot water temperature, but usually during hot water
production.
The hot water heaters for DHP-A differ from the other heat pumps in
that the function for defrosting the outdoor unit is different.

Auxiliary heat

If the heat demand is greater than the heat pump's compressor
capacity, the auxiliary heater engages automatically in operating mode
AUTO. The auxiliary heater is made up of an electric heating element on
the supply line that has two outputs, AUX. HEAT 1 and AUX. HEAT 2, and
can be controlled in three steps. DHP-A has three outputs, AUX. HEAT 1,
AUX. HEAT 2 and AUX. HEAT 3 and output can be controlled in five
steps.
Table 1. auxiliary heater output steps in kW
DHP-H, DHP-L, DHP-C
230V
Step 1 1,5
Step 2 3
Step 3 4,5
Step 4
Step 5
Step +4
Step +5
The two power steps, step 4 and step 5 for DHP-A cannot be activated
when the compressor is running. Auxiliary heater step: +4 and +5 can be
DHP-A
400V 230V
3 1,5
6 3
9 4,5
User manual VUBMA902 – 9
400V
3
6
9
12
15
12
15