Product specifications

20
5. CONNECTIONS
5.1 Connect the CH system
1. Flush the CH system thoroughly.
2. Connect the flow and return pipes using the 22mm isolation valves.
All pipes must be mounted tension-free in order to avoid ticking of
the pipes.
Existing connections must not be twisted in order to avoid leaks at
the connections with the external pipes.
The CH system should be provided with:-
• A filling loop in the return pipe directly below the appliance.
• A drain tap at the lowest point of the system.
• An expansion tank. The HE26 comes complete with 6 litre
expansion tank. It may be necessary to fit an additional
expansion tank.
5.1.1 Expansion vessel
The HE26 appliance is fitted with a 6 litre expansion vessel which is
adequate for a system with a water volume not exceeding 100 litres,
typically 8 radiators. For larger volume systems, an additional expansion
vessel must be fitted. Atmos can supply a 12 litre or 18 litre Robokit.
The HE40C appliance is not fitted with an expansion vessel.
5.1.2 Thermostatic radiator valves
Building regulations require a room thermostat to be fitted on all
installations. Do not fit a thermostatic valve on the radiators in the room
where the thermostat is situated, otherwise the controls will not function
correctly.
5.1.3 System bypass
A by-pass is not required for safe operation of the boiler. For heating
systems where there are thermostatic valves on all radiators, or where
there are other system flow restrictions such as zone valves, a by-pass
should be fitted to reduce system noise and to protect the pump. The by-
pass should comprise a proprietary by-pass valve with adjustable flow
regulation, not a fixed setting valve. Atmos can supply this valve.
Note
The flexible tube from the pressure relief safety
valve can be inserted directly into the waste pipe if
suitably located. The flexible tube must be installed
so that there are no sharp bends that kink the pipe
and cause a restriction in the flow.