The water in the underfloor heating system must flow in order to convey heat to the floor.  The size of the water flow is determined by the amount of heat to be conveyed and the designed water temperature drop.

Depending on the interior of a house, the rooms are of different size.  This means that the heat requirement will be proportional to the area of each room.  In an underfloor heating system the pipe loops will have different length.  Normally, the largest room will have the highest water flow.

In a house there might be different rooms with different heat requirements depending on the location of the rooms, number of outer doors and windows.

The minimum water velocity required in order to drive air bubbles varies with the pipe size.  However, in a small house there might be small rooms requiring low water flow, which results in a low water velocity.

In order to dimension the underfloor heating pump capacity for the underfloor heating system, data about total pressure drop and flow must be available.

It is always recommend that the water underfloor heating system is explained to the customer, ie location of manifolds and the room they serve.  The function of the underfloor heating room thermostats should be explained and which loops they control on the underfloor heating manifolds.

It should be explained that the underfloor heating system is comparatively slow in responding to alterations to their control system settings.  One to two hours is a normal delay for underfloor heating water to any changes in room temperature.

The underfloor heating thermostat setting for each room should be shown to the customer.  These should also be noted in the user instructions for the underfloor heating water system.  If the user knows how to operate the underfloor heating system, it will save on the underfloor heating cost.

The boiler should be serviced annually by a CORGI approved installer.  The underfloor heating manifolds should be checked to ensure that there are no leaks on unions.  The system should be treated with corrosion inhibitor as this will probably be a warranty requirement of the boiler manufacturer.