1.
To obtain the best performance from your OSO unvented system it is advisable to feed the unit
with an uninterrupted supply.
2.
Locate the water heater in a suitable position to facilitate the installation of the cold water supply,
discharge fittings and pipework. Also take into account access to the immersion heaters and the
commissioning valve.
3.
Fit the combined male elbow / drain cock to cold supply point (13), so that the compression
fitting is vertical.
4.
Fit the commissioning valve (12) to the commissioning fitting.
5.
Fit the female outlet of the tee piece to the temperature and pressure relief valve (5) with the
horizontal connection facing right at approx. 45°.
6.
Fit the tundish (6) to the tee piece using a short length of 15mm copper tube.
7.
Fit the length of copper tube 22mm specified in Table 2 to the cold feed elbow (see 3 above).
8.
Fit the pressure reducing valve(3) to the top of the copper tube (see 7 above), so that the black
knob is facing right.
9.
Connect the flexible hose to the 1/2'' outlet of the expansion valve (4) and the horizontal outlet
of the tee piece (see 5 above). Discard compression nut & ring.
10.
If a balanced mains pressure cold water supply is required to
a shower or bidet (over rim type
only, ascending spray type requires type AA,AB or AD air gap),
remove the blanking cap
from the pressure reducing valve (3) and connect to the shower or bidet cold supply.
(Major
shower manufacturers advise fitting a mini expansion vessel in the balanced cold supply
pipework to accommodate thermal expansion and prevent tightening of shower controls)
Using the balanced cold connection to feed outlets that do not require a balanced cold
supply can reduce the flow available to the unvented cylinder.
11.
Before connecting the cold supply, flush the cold supply pipework of all flux and debris.
12.
Connect the cold supply to the pressure reduction valve (Multibloc) (3).
Hot water supply
13.
Connect the hot water supply pipe to the outlet (9). Ensure connection is water tight.
Secondary return
14.
A secondary return facility is provided on all units. Fit a 1/2''F x 1/2''M x 15mm tee piece between
the commissioning valve (12) and the commissioning fitting. See also figure 5 on page16.
Discharge pipe
15.
Connect the discharge pipe from the tundish (6). This must have a continuous fall and be fitted
in accordance with The Building Regulations (see pages 5 and 12).
Primary flow & return and motorised valve (Indirect only)
16.
The boiler primary flow and return connections should be made to the unit and include a by-pass
with automatic by-pass valve. The motorised valve must be fitted into the primary heating circuit.
17.
For electrical connection of the motorised valve and immersion heater, please read Electrical
Installation Instructions. (Pages 7 - 11)
COLD WATER SUPPLY
-3-
