Honeywell
Honeywell DT4 Room Thermostat DT40WT20
Wired on/off room thermostat from Honeywell's DT4 range, in white, for controlling heating demand in domestic systems.
At a glance
- Also known as 4200666
£37.85
£31.54 ex. VAT · VAT at 20%
Same-day dispatch
Ordered by 4pm Mon–Fri, 10:30am Sat.
30-day returns
Unused, in original packaging.
What it is
The Honeywell DT40WT20 is a wired on/off room thermostat from the DT4 range. It switches the heating demand signal to the boiler or zone valve according to the room temperature set point. It is supplied in white for wall-mounted domestic installations.
Signs this part needs replacing
- The boiler continues to run when the room is above the set temperature
- The heating does not come on when the thermostat is turned up
- The thermostat clicks but the boiler or zone valve does not respond
- The room temperature drifts noticeably from the set point
- Operation becomes intermittent, or the thermostat no longer switches reliably
Before you order
- Confirm the existing thermostat is a wired on/off type and not a modulating or programmable unit
- Check the number of wires at the existing wall plate and whether a neutral is present
- Verify the model number on the existing thermostat matches DT40WT20
- Confirm the boiler or zone valve is controlled by a simple switched live demand signal
Compliance
| Alternative numbers | 4200666 |
|---|
| Make | Model / assembly | Reference | Years | Fitment |
|---|---|---|---|---|
| SPECIAL OFFERS Honeywell Controls | — | — | — |
Documents & drawings
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