To programme an EPH thermostat, identify the exact model and select the correct schedule pattern before editing any times. Popular EPH CP4 and RFRP programmable thermostats can use a weekday/weekend programme, an individual seven-day programme or the same 24-hour programme every day. Many allow six temperature events per day.
EPH also makes separate programmers that switch heating zones on and off. A programmable thermostat uses time-and-temperature events; a programmer uses on-and-off periods. Read the model name before following any button sequence.
Find the exact EPH model
Look on the front, under a flap, beside the battery compartment or in the paperwork for a code such as CP4 V2, CP4B, RFRP V2 or CDTP2. Do not pull a wired control from its backplate or open a receiver. EPH’s official download centre groups guides by product family.
The CP4 V2 package uses an RFRP V2 wireless room thermostat with an RF1B receiver. The CP4B is a battery-operated programmable thermostat. CDTP2 is a hardwired programmable thermostat. Their concepts are similar, but buttons and menu routes are not identical.
Understand the three programme patterns
- 5/2 day: Monday to Friday share one schedule, while Saturday and Sunday share another.
- 7 day: every day can have six individual time-and-temperature events.
- 24 hour: all seven days use the same six events.
EPH factory settings commonly use 5/2 day mode. Keep that pattern if the household follows a regular working week. Use 7-day mode for varying shifts or activities. Use 24-hour mode for a consistent daily routine.
Set the clock and programme mode first
On the RFRP V2 used with CP4 V2, open the time-setting route shown in the official guide, then use plus and minus to set the year, month, day, hour and minute, confirming each entry with OK. Select 5/2d, 7d or 24hr when the programme-mode option appears.
Button labels differ across EPH models. On CDTP2, the Set button opens date, time and mode settings. If the display sequence does not match, leave the settings unchanged and use the exact manual. A wrong clock can make a correct heating programme appear faulty.
Programme EPH CP4 V2 or RFRP V2 in 5/2 day mode
The official CP4 V2 guide uses six events labelled P1 to P6. To edit the weekday and weekend blocks:
- Press PROG once.
- The Monday-to-Friday block is selected.
- Use plus or minus to set the P1 start time, then press OK.
- Use plus or minus to set the P1 target temperature, then press OK.
- Repeat for P2 through P6.
- After the weekday block, the Saturday-to-Sunday block appears.
- Set its P1 to P6 times and temperatures in the same way.
- Press AUTO to return to normal automatic operation.
Some EPH cylinder controls use on/off status rather than a room-temperature target. If the screen asks for ON or OFF, you may be holding a cylinder thermostat or programmer, not the room thermostat described here.
Programming 7-day mode
In 7-day mode, enter P1 to P6 for the selected day. Use the day-advance control described in the model guide to move to the next day. On supported RFRP models, the Copy button can copy a completed day’s settings to other days. EPH says the copy function is available when the thermostat is in 7-day mode.
Programme one representative weekday carefully, copy it only to matching days, then edit exceptions. Check each copied day before leaving programme mode.
Programming 24-hour mode
In 24-hour mode, the same six time-and-temperature events apply to every day. Enter P1 through P6 once and return to Auto. This mode is useful when the household routine is steady and avoids unnecessary day-by-day editing.
What the six events mean
Each event changes the target room temperature from its start time until the next event. P1 might establish the morning comfort temperature, P2 a lower target after people leave, P5 an evening target and P6 an overnight target.
The thermostat is not simply on between two times. If the room is already warmer than the target, it does not ask for heat. If the room is cooler, it requests heat until the target is reached, subject to normal control cycling and the heating system responding.
Build a useful programme
- Write down normal wake, leave, return and bedtime times.
- Choose a comfortable occupied target.
- Choose a lower target for empty or sleeping periods.
- Enter only genuine changes; unused events can repeat the preceding target.
- Review weekday and weekend blocks separately.
- Run the programme for several days before making small adjustments.
Do not use an extreme target to try to warm the home faster. The thermostat controls the final room temperature; warm-up speed depends on the boiler, emitters, flow temperature and heat loss.
Auto, Manual and Off modes
EPH’s CP4 V2 provides Auto, Manual and Off operating modes. Auto follows the programme. Manual maintains the temperature you select instead of moving through scheduled events. Off stops normal scheduled heating demand, although frost-protection behaviour may still apply.
After programming, make sure AUTO is displayed. A thermostat left in Manual is one of the simplest reasons a new schedule appears to be ignored.
Temporary and permanent overrides
On compatible EPH thermostats, pressing plus or minus in Auto creates a temporary temperature override. The model guide explains when it ends, commonly at the next programmed event. A Hold or Manual function maintains a selected target until cancelled.
Use a temporary override for an unusual day. If the same change is needed repeatedly, edit the programme. Always return to Auto when you want the schedule to resume.
Optimum Start and early heating
Some EPH programmable thermostats provide Optimum Start. This feature starts the heating before a programmed comfort event so the room is closer to the target at the event time. It can make the boiler appear to start early even though the schedule is working as designed.
Check the exact model guide before changing advanced settings. Change one setting at a time and compare behaviour over similar days.
Keypad lock
When a lock symbol is visible, ordinary buttons may not change the programme. The RFRP V2 guide instructs users to hold the two temperature-adjustment buttons together for ten seconds to lock or unlock. CDTP2 guidance uses a five-second hold. Follow the timing for the exact model.
Why the schedule is not working
- The date or clock is wrong.
- The thermostat is in Manual or Off rather than Auto.
- 5/2, 7-day or 24-hour mode is not the pattern you expected.
- A temporary override remains until the next event.
- A Hold function is maintaining one target.
- Optimum Start makes heating begin before an event.
- The keypad is locked.
- The room is already above the target.
- The thermostat requests heat but the receiver or boiler does not respond.
First compare the displayed room temperature with the target. Then check mode, current event and heat-demand symbol. This identifies whether the control is declining to call for heat or the heating system is failing to answer.
What the wireless and heat symbols tell you
The wireless symbol indicates communication status on RF models. The heating symbol indicates that the thermostat is requesting heat. Neither proves that the boiler flame is established. Check the receiver lights and boiler display without opening either enclosure.
If the wireless symbol is missing or the receiver does not respond, use only the homeowner pairing or troubleshooting steps in the exact EPH guide. Do not touch receiver wiring.
Changing batteries safely
Where the thermostat is battery-powered, fit the battery type stated in its manual, replace the set together and observe polarity. Recheck the clock and programme afterwards. Do not open a mains receiver or hardwired thermostat to search for batteries.
EPH programmer or thermostat?
EPH R17, R27 and R37 products are timeswitches or multi-zone programmers. They use on and off periods rather than six room-temperature targets. If your wall control has zone Select buttons or asks for ON and OFF times, use its programmer guide.
The room thermostat and central programmer can both influence heating. A thermostat may request warmth while the programmer’s heating channel is off. Record both screens when diagnosing a timing problem.
When programming is not the fault
If the heat-demand symbol appears but the boiler remains in standby, or the receiver indicates demand without heating, the problem may involve wireless communication, receiver output, a zone valve, wiring or the boiler. Do not open the receiver, wiring centre or boiler case.
Record the EPH model, operating mode, room and target temperatures, receiver lights and boiler display. That evidence helps an engineer test the correct part of the control chain.
Frequently asked questions
How many events can an EPH CP4 thermostat use?
Current CP4 V2 and related RFRP guidance describes six time-and-temperature events per day.
What is 5/2 day programming?
Monday to Friday share one schedule and Saturday to Sunday share another.
Why does the heating start early?
Optimum Start may preheat so the target is reached at the programmed time.
Why does changing the temperature not alter tomorrow?
A temporary override changes the current target only. Edit the programme to make a repeating change.
Why are my buttons doing nothing?
Check for the keypad-lock symbol and use the unlock sequence in the exact model guide.
Related boiler-help guides
- Thermostat says heating but the boiler is off
- Heating comes on at the wrong time
- What is a smart thermostat?
- How to programme a Drayton thermostat
Thermostat calling but no heat?
Book a fixed-price boiler diagnosis to check the controls and heating response.