Underfloor Heating- Single Zone System
The system must be filled with water and fully vented of air. This can be
best achieved using mains pressure through the two filling valves at the end
of the manifolds. All valves should be closed and the flow filling valve
connected with a hose to the mains water supply, with the return filling
valve connected to a hose laid to a wastewater point.
One by one the flow and the return valves are opened and closed purging the
loops of air. Ensure that all the blue caps on the return manifold are
closed. Open the upper ring on the end cap 2 to 3 turns. Open the first blue
cap and then open the return end cap. Wait until clear water is coming out
and make sure that all the air is gone. Close the blue cap and do same for
the next loop. Continue the process until all the loops are fully vented of
all the air. Close the end caps when done.
When this is completed and the filling valves closed off, the pumps should
be run for five minutes and the air vented again at the air bleed valve on
the filling valves until all air is bled from the system. Do not fill the
system from the boiler filling loop.
The system should be pressure tested with 6 bar for 24 hours before
screeding.
The manifolds are supplied with options for individual control for each
room. On the return manifold (the blue caps), actuators can be mounted for
individual control. If a programmable room thermostat with a two port valve
is controlling the system and there is no individual control, the “blue
caps” should be left open. The flow manifolds are supplied with flow gauges.
To adjust the flow gauges, us the key provided with the manifolds. See
instructions included in the manifold box on how to adjust the flow meters.
The following is an approximate guide, as how far each loop should be
adjusted;
Size of Loop Percentage Open
10 – 30 metres 30 % open
40 – 60 metres 50 % open
60 – 90 metres 75 % open
90 – 100 metres 100 % open
If the return manifold is not getting warm, there is either air in the
system or the flow and the return from the boiler is not correct fitted to
the mixing valve. Run the pump on speed 3. The system must be on for 24
hours to confirm that all the loops are working.
Note, if there is a risk for the air temperature dropping below freezing,
then you must protect the pipes and manifolds from freezing. It is always
recommended to lay screed on top of the pipes as soon as they have been
pressure tested.