Akva Vita TDP-F - district heating flat station for direct HE and DHW
Instructions
DH-SMT/PL
VI.KR.Z1.02 ©
Danfoss 09/2006
8
Troubleshooting
DHW
Problem
Possible cause
Solution
In general: Does the PM
controller work incorrectly?
If the quantity of tapping water
is normal (temperature
unimportant) it indicates that the
PM controller works correctly.
Locate defect in another part
of the installation
(see below)
In general: Are the operating
conditions satisfactory?
The flat station requires a DH
supply temperature of minimum
60 °C and a differential pressure
during operation according to the
information stated in the product
sheet for Akva Vita TDP-F.
Contact district heating
supplier.
PM controller leaking;
Water leaking from Allen
screws at the central part of
PM controller.
One of the two O-rings is defective
(does not influence the PM
operation). If a non-return valve is
installed in the DCW inlet (e.g. in
the house service connection or in
DCW meter) a safety valve should be
mounted between the non-return
valve and the heat exchanger.
Replace PM controller
(use new sealing).
DHW tap load too low
The diaphragm of the PM controller
is defective.
Replace diaphragm
or PM controller.
DHW tap load too low;
Tap temperature too low;
Tap temperature fluctuates;
PM controller wrongly
adjusted,
Strainer in DH supply clogged,
Defective non-return valve in
thermostatic battery (DHW tap
temperature lower than DHW from
flat station),
Defective non-return valve in hot-
water circulation (circulation return
pipe is getting cold during tapping
of hot water),
Lime scale precipitation in the plate
heat exchanger for DHW (primary Δt
too low during DHW tapping),
Dirt in PM controller,
DCW flow too high (big nominal
diameter of pipe, high DCW
pressure), in total max. 16-17 litres
per minute.
Setting, see
Regulation
chapter.
Clean strainer.
Clean or replace non-return
valve.
Clean or replace non-return
valve.
Replace the plate heat
exchanger.
Cleaning, see
PM controller
instruction.
DCW reduction.
DH return water temperature
too high while on standby;
The plate heat exchanger is
cold…
The by-pass thermostat is defective
or wrongly adjusted.
Replace or adjust by-pass
thermostat correctly
DH return water temperature
too high while on standby;
The plate heat exchanger is
hot…
Dirt (sand, iron splinters or similar)
in PM controller. Controller does not
close. Noise from flow can often be
heard.
Move handle several times
between red and blue
markings; at the same
time do several hot-
water tappings. Clean PM
controller.
Primary return temperature
too high during hot water
tapping.
Lime scale precipitation in the plate
heat exchanger for DHW
Replace plate heat exchanger
Connecting pieces of the PM
controller do not fit the flat
station
In particular when replacing PM
controller in old flat station
Loosen Allen screws; turn
half of the PM controller
180°
