20 ©ESP Ltd. Sept 2008
6.4 DRAINING THE UNIT
Switch off the electrical supply to the immersion heater(s) and heat pump. Turn
off the mains water supply to the unit. Attach a hosepipe to the drain cock hav-
ing sufficient length to take water to a suitable discharge point below the level
of the unit, at least one metre below the unit is recommended. Open hot water
tap nearest to the unit to relieve the system pressure. Open drain cock. If water
fails to drain from the unit vent the unit by manually opening the Temperature/
Pressure Relief Valve or “crack a joint” in the unit plumbing to prevent the
creation of a vacuum that may prevent effective draining.
6.5 DESCALING IMMERSION HEATER(S)
Open the cover(s) to the immersion heater housing(s) and disconnect wiring
from immersion heater(s). Remove the thermostat by carefully pulling out-
wards from the immersion heater. Unscrew immersion heater backnut(s) and
remove immersion heater from the unit. Over time the immersion heater gas-
ket may become stuck to the mating surface. To break the seal insert a round
bladed screwdriver into one of the pockets on the immersion heater and gently
lever up and down.
Carefully remove any scale from the surface of the element(s).
DO NOT
use a
sharp implement as damage to the element surface could be caused. Ensure
sealing surfaces are clean and seals are undamaged, if in doubt fit a new gasket.
Replace immersion heater(s) ensuring (where appropriate for the unit being
worked upon) the lower (right angled) element hangs vertically downwards
towards the base of the unit. It may be helpful to support the immersion heater
using a round bladed screwdriver inserted into one of the thermostat pockets
whilst the backnut is tightened. Replace the thermostat(s) by carefully plugging
the two male spade terminations on the underside of the thermostat head into
the corresponding terminations on the element.
Rewire the immersion heater(s). Close and secure terminal cover(s).
6. Maintenance
6.6 REFILLING SYSTEM
DO NOT
switch on the immersion heater(s) or heat pump part of the unit
until the system has been completely refilled.
Close the drain tap. With the hot tap open, turn on mains water supply. When
water flows from the hot tap allow to flow for a short while to purge air and
to flush through any disturbed particles. Close hot tap and then open succes-
sive hot taps in system to purge any air. The electrical supply can now be
switched on.
6.7 LOG BOOK
Please complete any log book supplied with the unit stating what has been
done, the date of the service and the name/contact details of the servicing
engineer.
6.8 MAINTENANCE REQUIREMENTS (For Heat Pump)
C
heck the water supply and air vent frequently, to avoid lack of water or
air in the water loop. Clean the inline strainer regularly to maintain water
quality and check that the scale inhibitor is still working effectively. Re-
place as appropriate. Lack of water and dirty water can damage the unit.
The heat pump will start the water pump every 72 hours when it is not
running, to avoid freezing.
K
eep the unit in a place which is dry and clean, and has good ventilation.
Clean the heat exchanger every 1 or 2 months to maintain a good heat
exchange rate.
C
heck each part of the unit and the pressure of the system. Replace any
failing part, and recharge the refrigerant if it is necessary.
C
heck the power supply and the electrical system to ensure that all is in
order. If any part has failed replace it. Check for any unusual smells that
may indicate parts about to fail.
6. Maintenance
Hot water air source heat pump
Hot water air source heat pump
