Horstmann 425 Tiara User Manual

The Horstmann 425 Tiara and Diadem programmers are 2 circuit central
heating and hot water programmers able to switch ON and OFF twice
every 24 hours. An advance switch is provided to make temporary
overrides to the ON or OFF periods and a selector switch gives a further
choice of programmes.

Horstmann 425 Tiara/Diadem

Electro-mechanical Programmers

User Operating Instructions

1

The simple instructions contained in this user guide are designed to help with the programming and
operation of these units.

2

The 425 Tiara/Diadem Programmer

DIAL

DIAL

INDICATORS

TIME POINTER

TIME POINTER

SWITCH STATE

INDICATOR

SWITCH STATE

INDICATOR

PROGRAMME

SELECTORS

PROGRAMME

SELECTORS

ADVANCE
CONTROL

ADVANCE
CONTROL

TAPPETS

TAPPETS

425 TIARA

425 DIADEM