THERMAFLOW LTD | THERMAFLOW® ELECTRIC COMBINATION BOILER |
Tel: 0870 850 5207
31
WARNING: FOR YOUR OWN SAFETY
SERVICING AND MAINTENANCE SHOULD BE CARRIED OUT BY A PERSON WHO IS
COMPETENT TO DO SO.
3.2 MAINTENANCE
Before commencing, refer to section 1. Installation
Checking the pressure in the expansion vessel
3.2.1 The primary expansion vessel
(volume 25 or 30 litres) is the red or blue vessel connected to the
central heating boiler. Its purpose is to take up expansion in the boiler and central heating system.
The pressure can be accurately checked with the pressure relieved on the other side of the diaphragm.
To do this drain some water from the central heating system until the pressure gauge registers zero.
Connect a pressure gauge to the car tyre type valve on the vessel. The pressure should register
100
KPA
(
1.0 Bar
). Refill heating system as described in section
2.7.2
3.3.2 The secondary expansion vessel
(volume 0.5 litres) is the white or silver vessel connected to the
cold inlet of the boiler.
Its function is to take up expansion in the hot water pipe work and so protect the blender from damage.
The pressure can be accurately checked with the pressure relieved on the other side of the diaphragm.
To do this, isolate the water supply to the Thermaflow boiler and open a hot tap. Water will run for a few
seconds then stop.
Connect a pressure gauge to the car tyre type valve on the vessel. The pressure should register 200-350
KPA (2.0-3.5 Bar). Close the hot taps and turn the water supply back on.
3.2.3 Checking the inline strainer
Whilst the water is off, remove and clean the gauze in the brass strainer assembly. To remove the gauze
for cleaning un-screw the brass plug.
3.2.4 Checking the hot water blending valve
With the store temperature fully recovered, run a hot tap and check the flow rate and temperature.
If the hot water has deteriorated suddenly (over less than a month) then this points to a problem with the
blender.
A broken blender is usually linked to a loss of pressure in the secondary expansion vessel.
The expansion vessel protects the blender from damage when the water in the secondary system
expands as the water re-heats after water is drawn off.
