Heat Transfer Fluid; Filling - Bailey Pegasus Owner's Manual

62
• Check that all water has emptied out
(7–10 litres). Leave the valve in the open
position until the next time the hot water
cylinder is used.
Check that the breather valve (Fig.1 [N]) is
allowing air to enter the hot water cylinder
when it is being drained, and that the clear
plastic hose is not obstructed.
Fig.1
H T
EAT RANSFER
The central heating system is filled with
heat transfer fluid (HTF), a solution of 50%
ethylene glycol antifreeze and 50% water.
F
LUID
The boiler must not be switched on if
there is no HTF in the system.
The antifreeze manufacturer will have a
maximum water hardness recommendation.
Read the product label or contact the product
manufacturer for details.
Alde recommends antifreeze meeting VAG
G12++ or G13 specification, and deionised water
(0 ppm).
50:50 ethylene glycol antifreeze and water
will protect against frost down to -35 to 37°C.
A refractometer and/or hydrometer can be
used to measure the strength of the antifreeze
solution.
Corrosion protection will vary depending on
the lifespan of the antifreeze. Contact the
product manufacturer for details.
Always replace the HTF in accordance
with the antifreeze product's lifespan.
If in any doubt, replace the HTF after
2 years.
The corrosion inhibitors found in ethylene
glycol antifreeze may not be cross-compatible.
When topping up or replacing the HTF, ensure
the new antifreeze is compatible with the
current antifreeze product. Read the product
label or contact the product manufacturer for
details.
As a rough guideline, blue and
red antifreeze products are not
compatible with each other, but VAG
G12++ and G13 spec antifreeze (purple/
magenta) is compatible with both.
Failure to fill with suitable HTF may
result in severe damage to your Alde
system, which is not covered under
warranty.
F
ILLING
The central heating system is filled with HTF
through the expansion tank either by hand or
by using the Alde service pump. Any containers
used for handling or storing the HTF should be
checked first and must be visibly clean to avoid
introducing contaminants or foreign objects
into the system.
Alde recommends using the Alde 1900-811 or
839 twin-motor service pump to fill the system.
To fill the system by hand, unscrew the