Service & Replacement Of Parts - Potterton Powermax HE 85 Litre Installation And Servicing Instructions

4. Service & Replacement of Parts
To ensure safe, efficient operation of the boiler, it is
necessary to carry out routine servicing at regular
intervals. The frequency of servicing will depend upon the
particular installation conditions and the use to which the
boiler is put.
Important: Before commencing any servicing or
exchange of components, always turn off the gas
supply and isolate the electricity supplies (i.e. to
boiler and immersion heater).
An annual inspection is recommended with servicing
every other year. After completing any service work
always test for gas soundness and Remember to fill in
the Benchmark Log Book.
To gain access to the boiler for servicing, remove front
panel and top cover as described in Section 4.1 on Page
28.
Annually
Important: Any 'O' rings, seals, gaskets or washers
disturbed during service or replacement of parts must
be visually inspected and replaced if worn or
damaged.
1. Remove outer and inner top covers to gain access
to heat exchanger etc. Inspect components within
compartment, checking that joints are dry etc.
2. Withdraw the ionisation probe and clean the
electrode with wire wool or similar abraisive.
3. Partially open vent on top of heat exchanger and
release any trapped air. Partially unscrew cap on
auto air vent (on top of pump) and release air.
4. Draw hot water from a bath tap if necessary to
cause burner to light. Check ignition is smooth and
visually inspect flame. Continue to draw water until
maximum fan speed is attained. Check combustion,
see 'Combustion Testing'.
5. Turn off the mains water supply at the Inlet Control
Group and release system pressure by opening a
hot tap. Using hexagon key provided, remove the
pressure reducing cartridge from the Inlet Control
Group. Clean the cartridge and strainer in running
cold water (A replacement cartridge/strainer
element is available - Part No. 5106018). Re-fit the
cartridge ensuring that the strainer is correctly
located.
6. With no water pressure in the system, check and if
necessary adjust the secondary expansion vessel
Publication No. 5106226
pressure to approx. 2.5 to 2.8 bar (36 to 40 psi).
Note: Vessel pressure can not be accurately set with
water pressure in system.
7. Restore pressure to DHW system. Manually
operate, in turn, the expansion relief valve (part of
Inlet Control Group) and the temperature & pressure
relief valve (Fig. 10). Check that the discharge
route(s) is unobstructed and that water flows freely
to a safe, visible location. Check that both valves
close correctly.
8. Release CH system pressure via relief valve and
check primary expansion vessel pre-charge
pressure is between 1.0 to 1.2 bar. Adjust if required
and top up system to same pressure.
9. Check for gas soundness and re-assemble in
reverse order.
Every Second Year
1. Additionally to the above.
Remove the heat exchanger door complete with
burner, see Section 4.7 - Burner. Inspect the burner,
combustion chamber and heat exchanger, carefully
clean using a vacuum cleaner. Check the tightness
of the nuts securing the burner to the heat
exchanger door. DO NOT separate the burner from
the heat exchanger door. Inspect the electrode
condition and check gap which should be 3.5 - 4.0
mm.
Combustion Testing
A combustion analysis test point is provided on the flue
outlet (just above heat exchanger). The test point is
tapped ⁄ BSP and is sealed by a special screw/'O' ring
assembly. For a correctly installed boiler typical values
to be expected are:
CO <80 ppm C0 2 <9.5 % at maximum input
Levels significantly above these should be investigated
and may indicate a defective component or faulty
installation. Ensure the test point is FULLY GAS
TIGHT. Do not substitute any other screw for the
special Powermax screw (Part No. 5106046).
Electrical Safety Testing
It may be necessary to carry out electrical test work to
ensure the safety of the boiler circuits after overhaul
or as part of an inspection programme. This should be
carried out to latest edition IEE regulations for Class 1
appliances with the flash test set at 1500 volts.
Service & Replacement of Parts
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