MPN: IMC
Single / Dual / Twin Element
Off-Peak Tariff Ready
7-Day Programming
Boost Function
Landlord PIN Lock
230V / 13A / IP20
The EPH Controls IMC Immersion Controller is a digital time-switch designed to control immersion heaters in domestic hot water cylinders — replacing older E7 (Electronic 7) timer units with a modern, feature-rich controller. Compatible with single, dual, and twin element 3kW immersion heaters, the IMC is designed specifically to take advantage of off-peak electricity tariffs (such as Economy 7 or Octopus Go) by scheduling the immersion heater to run during cheaper overnight or off-peak periods.
The IMC offers flexible 24-hour, 5/2 day, or 7-day individual day programming with up to 3 on/off periods per day, an instant BOOST function for quick heating on demand (30 min, 1 hr, 2 hr, or 3 hr), automatic summer/winter time adjustment, a Holiday function, keypad lock, and an optional PIN lock for landlord applications. A white-backlit LCD display provides clear visibility of settings and programme status. Supplied with its own surface mounting box and compatible with standard single or double gang flush back boxes — a direct replacement for most existing immersion heater timers.
13A
max resistive
Contact Rating
3
periods/day
Max Programmes
170 × 116 × 63
mm
Dimensions
0–45°C
ambient
Operating Range
Key Features
💡 Off-Peak Tariff OptimisedDesigned to maximise savings from Economy 7, Economy 10, and other time-of-use electricity tariffs. Programme the IMC to heat the cylinder during off-peak overnight hours at lower electricity rates — then use the Boost function for top-up heating during the day if needed.
📅 7-Day Individual Day ProgrammingChoose from 24-hour (same programme every day), 5/2 day (weekday/weekend split), or full 7-day individual programming — up to 3 on/off periods per day. Full flexibility to match the household's actual hot water usage pattern across each day of the week.
🔥 BOOST Function — 4 DurationsPress the dedicated BOOST button for instant on-demand heating — choose 30 minutes, 1 hour, 2 hours, or 3 hours. The unit heats the cylinder for the selected duration, then automatically reverts to the timed programme. LED indicators show when the controller is in timed or boosted demand.
🕐 Auto Summer/Winter TimeAutomatically adjusts the clock for British Summer Time (BST) and Greenwich Mean Time (GMT) changes — no manual adjustment needed when the clocks change. This ensures off-peak timing remains accurate without any user intervention.
🔒 Landlord PIN LockAn optional PIN lock function prevents unauthorised changes to the controller's programme settings — particularly useful in rental properties, HMOs, and student lets where tenants should not need to change the immersion heater schedule. The PIN lock is set by the landlord or installer.
🛏️ Holiday FunctionSet the controller to OFF mode for a specified duration using the Holiday Function — the immersion heater will not run during the away period, eliminating unnecessary energy consumption when the property is unoccupied.
🔌 Dual Element ControlCompatible with single element, dual element, and twin element immersion heaters. For dual/twin element configurations, the IMC can be wired to control the boost (short element) and timed/off-peak (long element) circuits independently — correct wiring is detailed in the installation guide included with the unit.
🔧 Direct E7 ReplacementThe IMC is fully interchangeable with existing Electronic 7 (E7) immersion heater timer units — fits existing back boxes with no need to chase new wiring. Supplied with its own surface mounting box for new installations. A simple drop-in replacement for most existing immersion heater time-switches.
Technical Specifications
| Specification |
IMC Detail |
| MPN |
IMC |
| Power Supply |
230V~ 50Hz |
| Power Consumption |
10mA |
| Contact Rating |
230V~, 50Hz, max 13A resistive |
| Compatible Immersion Heaters |
Single element, dual element, twin element (3kW) |
| Dimensions (H × W × D) |
170mm × 116mm × 63mm |
| Programming Modes |
24-Hour / 5-2 Day / 7-Day individual |
| Periods per Day |
Up to 3 on/off periods |
| Boost Durations |
30 min / 1 hr / 2 hr / 3 hr |
| Ambient Temperature Range |
0°C to 45°C |
| Humidity Range |
5–95% RH |
| IP Rating |
IP20 |
| Display |
White backlit LCD |
| Battery |
LIR2032 (for memory backup) |
| Memory Backup |
Internal |
| Auto Time Adjust |
Automatic BST/GMT summer/winter changeover |
| PIN Lock |
Yes — optional landlord PIN lock |
| Holiday Mode |
Yes |
| Mounting |
Supplied with surface box; compatible with single or double gang flush back box |
| Standards |
EN 60730-1, EN 60730-2-7; UKCA marked |
| Impulse Voltage Rating |
2kV (per EN60730) |
| Automatic Action Type |
1C |
| Brand |
EPH Controls |
Frequently Asked Questions
Will the IMC replace my existing Economy 7 timer?
Yes — the EPH IMC is designed as a direct replacement for existing Electronic 7 (E7) immersion heater controller units. It is compatible with standard back boxes (single or double gang flush) and comes with its own surface mounting box for new installations. No rewiring is required in most replacement scenarios — simply swap out the old controller and wire the IMC to the existing terminals following the wiring diagram supplied with the unit.
How does the IMC work with dual element immersion heaters?
A dual or twin element immersion heater has two separate heating elements — typically a short "boost" element at the top of the cylinder and a long "overnight/off-peak" element that heats the full cylinder. The IMC can be wired to control both elements independently: Terminal 4 is for the boost (short) element and Terminal 5 for the timed/off-peak (long) element. The wiring diagram on page 8 of the installation guide shows the correct configuration. Refer to the guide carefully for dual element installations.
Can the IMC be used with Economy 7 (E7) and similar tariffs?
Yes — this is its primary design purpose. Programme the timed schedule to run the immersion heater during your off-peak tariff window (e.g. 00:30–07:30 for a typical E7 overnight period), and the unit will heat your cylinder using low-cost electricity overnight. Use the Boost function during the day for top-up heating when required. Over a year, this scheduling approach can generate significant electricity cost savings compared to running the immersion heater on a standard rate tariff.
What does the PIN lock do — does it prevent the Boost button from working?
The PIN lock function prevents changes to the programmed settings — so tenants or building users cannot alter the scheduled heating times. However, the Boost button can typically still be used to add on-demand hot water without unlocking the PIN — this is by design, as users should still be able to get hot water when needed. The PIN lock is specifically for protecting the programming from being changed, not for restricting all operation.
⚠️ Note: Installation must be carried out by a qualified electrician. Isolate mains supply before installation and ensure unit is properly earthed. The IMC is rated at 13A maximum — do not use with immersion heaters greater than 3kW on a single element circuit. Supplied with surface mounting box — compatible with standard single or double gang flush back box. UKCA marked. Conforms to EN 60730-1 and EN 60730-2-7.
