Honeywell DT90E Digital Room Thermostat User Guide
- October 27, 2023
- Honeywell
Table of Contents
Honeywell DT90E Digital Room Thermostat
User Guide
- Room temperature
- Set temperature, inquiry
- Set temperature, adjustment
- Switch ON/OFF (frost protection enabled)
Operating indicators
- Heating demand indicator
- Frost protection
- Fault indicator
- Low battery indicator
- Heat/cool changeover
Energy Saving ECO feature
-
Pressing the green ECO button gives a timed period at a different, predefined temperature.
-
To set the ECO energy savings time period.
-
Display shows countdown of ECO time remaining.
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Pressing or will now allow the ECO temperature to be changed.
-
To exit ECO mode, press ECO button again.
What is a room thermostat
an explanation for householders
| A room thermostat simply switches the heating system on and off as
necessary. It works by sensing the air temperature, switching on the heating
when the air temperature falls below the thermostat setting, and switching it
off once this set temperature has been reached. Turning a room thermostat to a
higher setting will not make the room heat up any faster. How quickly the room
heats up depends on the design of the heating system, for example, the size of
boiler and radiators.|
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Neither does the setting affect how quickly the room cools down. Turning a room thermostat to a lower setting will result in the room being controlled at a lower temperature, and saves energy.
The heating system will not work if a time switch or programmer has switched it off.
The way to set and use your room thermostat is to find the lowest temperature setting that you are comfortable with, and then leave it alone to do its job. The best way to do this is to set the room thermostat to a low temperature – say 18ºC – and then turn it up by one degree each day until you are comfortable with the temperature. You won’t have to adjust the thermostat further. Any adjustment above this setting will waste energy and cost you more money.
If your heating system is a boiler with radiators, there will usually be only one room thermostat to control the whole house. But you can have different temperatures in individual rooms by installing thermostatic radiator valves (TRVs) on individual radiators. If you don’t have TRVs, you should choose a temperature that is reasonable for the whole house. If you do have TRVs, you can choose a slightly higher setting to make sure that even the coldest room is comfortable, then prevent any overheating in other rooms by adjusting the TRVs.
Room thermostats need a free flow of air to sense the temperature, so they must not be covered by curtains or blocked by furniture. Nearby electric fires, televisions, wall or table lamps may prevent the thermostat from working properly
This product and its associated documentation and packaging are protected by various intellectual property rights belonging to Honeywell Inc and its subsidiaries and existing under the laws of the UK and other countries. These intellectual and property rights may include patent applications, registered designs, unregistered designs, registered trade marks, unregistered trade marks and copyrights. Honeywell reserves the right to modify this document, product and functionality without notice. This document replaces any previously issued instructions and is only applicable to the product(s) described. This product has been designed for applications as described within this document. For use outside of the scope as described herein, refer to Honeywell for guidance. Honeywell cannot be held responsible for misapplication of the product(s) described within this document.Manufactured for and on behalf of the Environment and Combustion Controls Division of Honeywell Technologies Sàrl, ACS-ECC EMEA, Z.A. La Pièce 16, 1180 Rolle, Switzerland, by its Authorised Representative Honeywell Inc
Installation
Installer Mode
- To enter Installer Mode
- To select a parameter
- Display
- Parameter flow-chart
- To change a parameter
- To exit Installer Mode
Parameters
| Description | Parameter | Range of values | Default |
|---|---|---|---|
| Minimum ON/OFF time | Ot | 1,2,3,4,5 m | 1 m |
| Cycle rate | Cr | {3,6,9,12} | 6 |
| Proportional bandwidth | Pb | 1.5 … 3.0 K | 1.5K |
| Temperature measurement offset | tO | -3 … 3 K | 0 K |
| Upper setpoint limit | uL | 21 … 35 °C | 35°C |
| Lower setpoint limit | LL | 5 … 21 °C | 5°C |
| Heat/cool changeover | HC | 0, 1 | 0 |
0 = Disable
Off setpoint adjust| OS| — (= Off), 5…16°C| 5°C
Electric heat| EH| 0 (<3A) / 1 (3A – 8A)| 0 (<3A)
Reset parameters| FS| 0 / 1| 1 (factory)
Pittway Sarl, Z.A. La Pièce 4,
1180 Rolle, Switzerland
Country of origin: UK
www.resideo.com
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International Inc. This product is manufactured by Resideo Technologies, Inc.
and its affiliates.