Honeywell DT90 - User Manual

The Honeywell DT90 Digital Room Thermostat is a smart climate control device designed for energy-efficient temperature management in residential heating and cooling systems. This manual covers its core functionalities, including advanced features like self-learning TPI (Temperature Programming Interface) control, frost protection, and the ECO mode for temporary energy savings. It also addresses installation requirements–such as proper mounting, wiring compatibility for various HVAC setups (boilers, heat pumps, electric heating), and technical specifications like electrical ratings and environmental limits. The documentation highlights Installer Mode for customizing settings like cycle rates, proportional band width, and temperature offsets to optimize performance for specific applications.

Page 1 – Product Specifications and Energy Saving Features
Page 2 – Display Layout and Technical Specifications
Page 3 – Main Features and Advanced Controls
Page 4 – Physical Installation Instructions
Page 5 – Wiring Connections and Dimensions
Page 6 – Installer Mode Application Settings
Page 7 – Installer Mode Parameter Adjustment Guide
Page 8 – Configuration Flowchart and Energy Optimization

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EN0H 8578 UK07 R1 12/08

DT90

DIGITAL ROOM THERMOSTAT

PRODUCT SPECIFICATION SHEET

The new

DT90

family of digital room thermostats is a

range of market leading products designed to provide
comfort with economy in modern heating systems.
Its large display and simple button interface make

DT90

extremely easy to use.

Energy efficiency is addressed by state-of-the-art TPI
control performance and an

ECO

button energy saving

feature.

Applications include control of gas or oil-fired boiler
systems, underfloor heating, electric heating and zoning
systems.

W ith a modern fresh look that complements any style of
décor, and a range of valued features for users and
installers alike,

DT90

sets the standard for simple

environmentally-friendly room thermostats.

FEATURES



Energy saving TPI control performance



Advanced self-learning control adapts to the
environment and ensures close temperature
control with minimum energy usage



Slim modern styling



Large high contrast display with easy-to-read
characters



Simple user interface



Temperature setting procedure eliminates the
risk of accidental setpoint change



Display shows room temperature, with option
to inquire about setpoint



5°C to 35°C setpoint range with 0.5°C
increments



Temperature set using up or down buttons



Off/standby button, allowing manual switch off,
with frost protection active



Adjustable off/standby setpoint 5°C to 16°C or
DT90 can be set to off completely



Battery powered by 2 x AA (LR6) alkaline cells



Up to 4 years battery life (minimum 2 years),
with battery low warning



Simple battery change by unclipping front
cover



Installer Mode allows the thermostat to be
customised for the application and the needs of
the user



NVRAM storage of setup parameters, ensuring
these are never lost



Setpoint limits can be programmed in



24…230Vac SPDT potential-free contacts for
simple 2-wire installation



8 A resistive, 3 A inductive switch rating



Surface or switch-box mounting options



Sensor fault self-diagnostics



Heat/cool changeover operation mode possible

FEATURES UNIQUE TO DT90E ECO MODEL



Energy saving ECO button allows user to
change to a lower, energy saving setpoint for a
timed period of

their choosing (1…24 hours)



Display shows countdown of time remaining in
ECO energy saving mode

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About this manual

Brand: Honeywell
Model: DT90
Document type: User Manual
Language(s): English
Pages: 8
File size: 662.7 KB
Format: PDF

Summary

Page 1 - Product Specifications and Energy Saving Features

Specification sheet detailing energy-saving TPI control, large display, user interface, installation options, and unique features of the DT90E ECO model.

Page 2 - Display Layout and Technical Specifications

Controls and display layout diagrams for models DT90A and DT90E, along with electrical requirements, temperature control capabilities, operating conditions, and physical dimensions.

Page 3 - Main Features and Advanced Controls

Ordering specifications, main features including frost protection and Installer Mode, NVRAM storage, self-learning TPI control, ECO function, and electrical ratings.