Ideal Thermostatic Valve HIU Underfloor Indirect 177772

The Ideal 177772 is a thermostatic valve intended for heat interface unit (HIU) applications serving underfloor indirect circuits. It is produced under the Caradon Ideal banner and forms part of the temperature control arrangement within the unit, regulating the flow of heated water so the underfloor loop is held at a stable, usable temperature. The valve is a serviceable component, so it can be renewed on its own rather than replacing the wider HIU assembly.

• The underfloor circuit runs cold or fails to reach its set temperature despite the HIU calling for heat.
• Flow temperature to the underfloor loop fluctuates or overshoots, causing discomfort or tripping of the manifold controls.
• The valve spindle is stiff, seized or does not respond when the temperature setting is adjusted.
• Water weeps from the valve body, spindle or connections.
• The valve no longer modulates, leaving the circuit either permanently open or permanently closed.

• Confirm the appliance model and serial number against the compatibility list before ordering, as the same HIU family can use different internal components.
• Note the alternative part number 1783155 so the correct item can be matched if the original reference is not shown on the unit.
• Inspect the surrounding seals and connections while the unit is open, and renew any that show hardening, flattening or staining.
• Work on the appliance should be carried out by a competent engineer, with the unit isolated and drained as required before the valve is removed.