Drayton RTS1 Thermostat Wiring Diagram
Drayton RTS thermostat wiring
Wall plate with the 230 V supply and the call-for-heat output; choose the model group.
Terminals and components · 5
- Live
- Neutral
- Call for heat
- Common (COM)
- L–1 link (if needed)
- Heating satisfied / cooling
- Earth loop
Connection
Run the neutral from the same 230 V AC, 50 Hz circuit that feeds terminal L.
Caution
- RTS thermostats are electronic with a relay output: without the neutral on N and the 230 V supply, the relay won't click and the call-for-heat contact stays open.
Function
Powers the thermostat and is the live that the SPST contact switches to terminal 3 on call for heat.
Caution
- Before switching on the mains, make sure the circuit fuse is 3 A.
- Disconnect the mains before fitting or removing the thermostat from the wall plate.
- The fixed wiring must include a switch with at least 3 mm contact separation in all poles.
Function
Only powers the electronics: the output contact is volt-free. If you need 230 V on the contact, fit a link between L and terminal 1.
Caution
- Before switching on the mains, make sure the circuit fuse is 3 A.
- Disconnect the mains before fitting or removing the thermostat from the wall plate.
- The fixed wiring must include a switch with at least 3 mm contact separation in all poles.
Use
These models have a single SPST contact between L and terminal 3, so they don't use the common or the rest contact of the changeover models.
How to power it
- Link L to 1 if the contact must switch 230 V (dashed line).
- Or a separate supply protected by a 3 A fuse.
- Without the link, the contact switches volt-free (useful with combi boilers).
Caution
- The contact is volt-free but not SELV: fixed wiring only.
- Contact rating: 2(1) A at 230 V AC.
Use
Connect here the equipment that must run when there is no heat demand, such as the cooling call of a cooling system.
Caution
- Contact rating: 2(1) A at 230 V AC.
Connection
Run this terminal to the switched-live (call for heat) input of the boiler, zone valve or programmer.
Caution
- Contact rating: 2(1) A at 230 V AC.
Connection
Closes to terminal 1 on call for heat: it delivers whatever voltage is on terminal 1 (230 V with the L–1 link) or acts as a volt-free contact.
Caution
- Contact rating: 2(1) A at 230 V AC.
Use
The thermostat is double insulated: this terminal only provides continuity for the cable's earth conductor, for convenience.
Check
- The figure doesn't label this terminal; check on the wall plate which one is the earth loop.
About This Diagram
This diagram is redrawn from page 4 of the Drayton RTS1 Thermostat Technical Specifications, and we offer it completely free and in English. We have also categorized it in the Thermostats (HVAC & Water Heating) section on Diagramverse, and it has been rated by 1 user with an average rating of 5.0. If you have any specific questions about the Drayton RTS1 Thermostat Wiring Diagram, we suggest checking the Frequently Asked Questions (FAQs) section.
Printable Drayton RTS1 Wiring Diagrams
Wiring Instructions
Before you start
First, find out which model you have. The model name is printed on the thermostat. Then choose the matching variant in the diagram. The Drayton RTS1, RTS2 and RTS3 switch 230 V live out of terminal 3, and terminals 1 and 2 stay empty. The RTS4, RTS9 and RTS10 have a volt-free changeover contact on terminals 1, 2 and 3. If you have an RTS1, use the RTS1 · RTS2 · RTS3 variant.
You will need:
- An insulated screwdriver set and wire strippers
- A voltage tester and a multimeter
- A drill, wall plugs and No 6 x 1 inch woodscrews for mounting on a flat wall, or M3.5 x 14 screws for a flush single conduit box
The RTS1 is for fixed wiring only. It must comply with current IET wiring regulations (BS7671). The fixed wiring must include a switch with at least 3 mm contact separation in all poles, so the thermostat can be fully cut off from the mains. The circuit feeding it must be fused at 3 A. The sources don't give a conductor size. Use a fixed-wiring cable suited to a 3 A fused circuit and to your local regulations. Mains work is notifiable in many places. If you are not competent with 230 V wiring, hire a qualified electrician.
Choose the mounting spot before you run any cable. It should be on an inside wall about 1.5 m (5 ft) above the floor. Keep it out of direct sunlight and drafts, and away from radiators or other appliances that give off heat. The RTS3 frost thermostat is different: put it in the coldest part of the building.
Step-by-step wiring
- Switch off and lock off the supply at the isolator. Remove the circuit fuse. Use your tester to confirm that every conductor is dead.
- Loosen the securing screws and take the thermostat off its wall-plate. For surface wiring, snap out the cable entry strip on the bottom edge of the wall-plate with pliers.
- Fix the wall-plate with the terminals at the top. Mount it directly on the wall or on a flush single conduit box.
- Strip each conductor just enough to sit fully inside its terminal, with no bare copper showing.
- Connect the supply neutral to N. This connection is not optional. The RTS1 is electronic and needs the neutral to power its relay.
- Connect the 3 A fused live to L.
- RTS1, RTS2 or RTS3: connect the switched live to the boiler, valve or other heating control to terminal 3 (Call for heat). Leave terminals 1 and 2 empty.
- RTS4, RTS9 or RTS10: put power on 1 (COM). You can add a link from L to 1, or feed it from a separate supply fused at 3 A. Connect the call-for-heat conductor to 3. Use 2 only if you need a "heating satisfied" or cooling signal. If the boiler needs a volt-free switch, leave out the L–1 link and connect the boiler's own two control wires to 1 and 3.
- Connect the circuit protective conductor to the E earth loop terminal. This keeps earth continuity through to the next device. The thermostat itself is double insulated and doesn't need an earth.
- Tighten every screw firmly. Then tug each conductor gently to check it is held.
- Plug the thermostat onto the wall-plate and tighten the securing screws.
Testing and start-up
- Before you restore power, check that the circuit fuse is 3 A. Then switch on.
- Turn the knob well above room temperature. You should hear the relay click, and the heating should start. On the RTS2 and RTS9, the LED should also light.
- On an RTS1, check with your multimeter that terminal 3 now reads about 230 V AC to N.
- Turn the knob well below room temperature. The relay should click off and terminal 3 should drop to 0 V.
- On volt-free models, isolate the supply before you test the contact. With your meter on continuity, 1–3 should be closed during a call for heat, and 1–2 should be closed when no heat is called.
- Set your comfort temperature against the setting mark. If you want to limit or lock the setting, pull off the knob, lift the two limiting arms, and rotate them into the notches you need. Then refit the knob with the same temperature against the mark.
Safety notes
- Every terminal can carry 230 V AC, including the volt-free contacts once L is linked to 1. These are not low-voltage (SELV) circuits. Treat all of them as mains.
- Always disconnect the mains before you fit the thermostat to its wall-plate or remove it.
- The switch rating is 2(1) A at 230 V AC. Don't switch pumps, heaters or other loads above this directly. Use a relay or contactor instead.
- Never feed terminal 1 from an unfused supply, or from a fuse larger than 3 A.
- Use the thermostat indoors only, in an operating temperature of 0 to 40 °C and non-condensing humidity.
Troubleshooting
| Symptom | Probable Cause | What to Check |
|---|---|---|
| Thermostat never clicks and the heating never comes on | The neutral is missing or loose, so the electronic relay has no power | Isolate the supply and check that the neutral is firmly in terminal N. Restore power and measure about 230 V AC between L and N. |
| Nothing happens at all, no click and no LED | The 3 A circuit fuse has blown, or there is no live on L | Check the fused spur or circuit fuse and replace it with a 3 A fuse only. Then measure about 230 V AC between L and N. |
| RTS4, RTS9 or RTS10 clicks but the boiler or valve never starts | No voltage on the common terminal 1 | If the load needs mains, fit a link from L to 1, or feed 1 from a separate 3 A fused supply. During a call for heat, terminal 3 should then read about 230 V AC to N. |
| Heating runs when the room is warm and stops when it gets cold | The call-for-heat conductor is on terminal 2 instead of terminal 3 | Move the call-for-heat conductor to terminal 3. Check continuity with the power off: 1–3 should close on demand, and 1–2 should close when the heat is satisfied. |
| Boiler won't respond after fitting an RTS1 in place of a volt-free stat on a combi | Wrong model: the RTS1 outputs switched 230 V live, but the boiler expects a volt-free contact | Check what the boiler's thermostat input requires. If it needs a volt-free switch, use an RTS4, RTS9 or RTS10 with no L–1 link. |
| Heating runs all the time, whatever the knob setting | Live is connected straight through to the call-for-heat conductor, or the existing wiring bypasses the thermostat | Isolate the supply. Confirm that the switched live goes only to terminal 3, and check that nothing links L or 1 directly to the boiler feed. |
| Fuse blows or the contact fails soon after start-up | The load connected to terminal 3 is above the 2(1) A rating | Check the current rating of the boiler, pump or valve. Above 2(1) A, switch the load through a relay or contactor. |
| Heating cuts in and out, or the temperature swings a lot | The thermostat sits near a radiator, in sunlight or in a draft, or a terminal screw is loose | Retighten all terminals with the power off. Move the thermostat to an inside wall about 1.5 m high, away from heat sources and drafts. |
| Knob won't turn above or below a certain temperature | The range limiting arms under the knob are set | Pull off the knob and lift and rotate the two limiting arms to the notches you need. Then refit the knob at the set temperature. |
| Earth continuity test fails further down the circuit | The earth conductors were not joined at terminal E | Join all the circuit protective conductors at the E earth loop terminal. Confirm continuity end to end. |
Frequently Asked Questions (FAQs)
Does the Drayton RTS1 need a neutral?
Yes, the RTS1 must have a neutral connected to terminal N. It is an electronic thermostat with a relay output, and the electronics need a 230 V AC supply to work. Without the neutral, the relay never operates, you won't hear a click, and the call-for-heat output stays off. Older mechanical thermostats often had no neutral wire. When you upgrade one of those, you may need to run a cable with a neutral to the thermostat position.
Is the RTS1 output volt-free?
No, the RTS1 output is not volt-free. It is a single-pole (SPST) switch that sends the 230 V live from terminal L out of terminal 3 when the room needs heat. The RTS2 and RTS3 work the same way. For a volt-free changeover contact, such as many combi boiler control inputs need, choose an RTS4, RTS9 or RTS10. Their terminal 1 is a common that you power only if the load needs it.
Do I need to connect an earth to the RTS1?
No, the RTS1 is double insulated and needs no earth. The E terminal is an earth loop terminal, there only for convenience. Use it to join the incoming and outgoing circuit protective conductors so earth continuity carries on to the rest of the circuit. Never leave a bare earth conductor loose in the back box. Sleeve it and terminate it at E.
What fuse should protect the RTS1?
A 3 A fuse should protect the RTS1. The thermostat is designed for a 230 V AC 50 Hz supply fused at 3 A. Check this fuse before you switch on for the first time. The fixed wiring must also include a switch with at least 3 mm contact separation in all poles, so you can fully isolate the thermostat. On volt-free models, any separate supply you feed to terminal 1 must also be fused at 3 A.
How much load can the RTS1 switch?
The RTS1 contact is rated 2(1) A at 230 V AC. The 2 A figure applies to resistive loads. The 1 A figure applies to inductive loads such as motors, pumps and valve actuators. Most boiler control inputs and zone valves are well within this rating. If you need to switch anything heavier, such as a circulating pump or an electric heater, let the thermostat drive a relay or contactor. That relay or contactor then switches the larger load.
Can the RTS1 replace my old thermostat?
Yes, the RTS family can replace earlier ACL and Drayton room thermostats, provided the load is no more than 2(1) A at 230 V AC. On an old Drayton RT or RTE, live 1 goes to L, neutral 4 goes to N, and call for heat 2 goes to terminal 3. Check the old thermostat's markings before you disconnect it. Label each conductor so it lands on the matching RTS terminal.
What is the temperature range of the RTS1?
The RTS1 controls room temperature from 10 to 30 °C, with a control accuracy under 0.6 °C. The RTS3 frost thermostat covers 3 to 10 °C instead, and the RTS10 covers 14 to 30 °C. You can limit the range or lock a setting with the two limiting arms under the knob. This is useful in rented properties or public areas.
Can I use the RTS1 to control cooling?
No, the RTS1 can't control cooling. It has a single heating output on terminal 3, and its terminals 1 and 2 are not used. If you need a "heating satisfied" or "call for cooling" signal, use an RTS4, RTS9 or RTS10. On those models, terminal 2 closes to the common terminal 1 when the room reaches the set temperature, and that can drive a cooling device or signal.
Can I mount the RTS1 on a back box or on the wall surface?
Yes, you can do either. Fix the wall-plate to a flush single conduit box with M3.5 x 14 screws, or straight onto a flat wall with wall plugs and No 6 x 1 inch woodscrews. For surface-run cable, snap out the cable entry strip on the bottom edge of the wall-plate with pliers. Always fit the wall-plate with the terminals at the top.
Where should I install the RTS1?
Install the RTS1 on an inside wall about 1.5 m (5 ft) above the floor, where air circulates freely. Keep it away from direct sunlight, drafts, radiators and other appliances that give off heat, because any of these will make it misread the room temperature. If you use an RTS3 for frost protection, put it in the coldest part of the building instead.
