Setup: Simple Life Potterton Promax Ultra Combi 28 User Guide

Content

Overview

The Potterton Promax Ultra Combi 28 is a wall-mounted, fully automatic condensing combination boiler designed to provide both central heating and mains-fed domestic hot water. It suits homes that need a compact combi boiler with straightforward controls, frost protection, and separate temperature adjustment for heating and hot water.

This model is part of the Promax Ultra Combi range and is intended for fully pumped sealed heating systems. It is also designed to prioritise hot water demand when needed, which helps keep everyday use simple in typical home heating setups.

Specifications

Model: Potterton Promax Ultra Combi 28
Boiler type: Condensing combination boiler
Fuel type: Natural gas as standard, with propane conversion support
Hot water output: 28 kW
Central heating output: 25.3 kW
System type: Fully pumped sealed heating systems only
Application: Central heating and mains-fed domestic hot water

Detailed description

The Potterton Promax Ultra Combi 28 uses separate controls for domestic hot water and central heating, letting you fine-tune each function independently. Its user interface includes a mode selector, temperature controls, a boiler status display, a burner indicator, and a pressure gauge for checking system conditions at a glance.

The boiler can run in summer mode for hot water only, winter mode for both heating and hot water, or heating-only mode when domestic hot water is not required. The integrated frost protection function helps protect the boiler even when it is left in standby, as long as power remains available.

For homes using time-based heating control, the connected thermostat or programmer can be set so the property is warm before waking up or before returning home. The system is built to work with external controls, and some button functions may also affect an optional outdoor sensor if fitted.

Safety

Keep the boiler powered if frost protection may be needed, because the anti-freeze function depends on mains electricity.
Do not assume a loss of heating or hot water means the boiler has failed; check the thermostat and programmer settings first.
If the boiler temperature drops below 5°C, the frost protection feature will operate automatically until the water warms up.
Press control buttons firmly for several seconds when changing settings, otherwise the selection may not register properly.

Setup and operation

Starting the boiler

Turn the mode knob to boiler off.
Set both the domestic hot water temperature knob and the central heating temperature knob to maximum.
Make sure all hot water taps are closed.
Switch on the boiler’s electricity supply and confirm that any external controls, such as the programmer and room thermostat, are switched on.
Turn the mode knob to the desired setting: summer mode for hot water only, or winter mode for heating and hot water.

Operating modes

Summer mode: domestic hot water only.
Winter mode: domestic hot water and central heating.
Heating-only mode: central heating only.

Hot water temperature

Use the hot water temperature buttons to raise or lower the set temperature.
The boiler limits domestic hot water to a maximum of 65°C through its controls.
Actual tap temperature can vary with flow rate, so a lower flow may feel hotter and a higher flow may feel cooler.

Heating and hot water timer control

The property thermostat can run a 7-day heating and hot water schedule.
If heating or hot water is not available, check that the correct programme and function selection are active.
In auto mode, temporary temperature changes can be made with the plus or minus buttons until the next programmed event.

Boost function

Press boost once for 1 hour of hot water or heating.
Press boost twice for 2 hours.
Press boost a third time to cancel the temporary boost and return to the normal schedule.

Display and controls

The display shows operating status, burner activity, heating request, domestic hot water request, pressure information, and service reminder messages.
Low water pressure, error states, and resettable faults are also shown on the display.
Buttons on the control panel include standby/reset/escape, boiler information view, heating temperature up and down, hot water temperature up and down, and the summer/winter/only-heating mode selector.

Troubleshooting

If there is no heating or hot water, first check the thermostat programme and confirm that the correct mode is selected on the boiler.
If the boiler display shows low pressure, inspect the system pressure and correct it if needed before trying again.
If the unit shows a resettable fault, use the reset function only after identifying that the issue is suitable for a reset.
If the display shows a non-resettable error or a generic fault, professional attention may be required.
If the burner is not starting, confirm that the boiler has power, the external controls are on, and the mode selection matches the required heating demand.

Pros & Cons

Pros: Separate heating and hot water controls make day-to-day use easy.
Pros: Frost protection works even in standby, provided power is supplied.
Pros: The 7-day thermostat scheduling supports comfort and energy savings.
Cons: Correct operation depends on thermostat and programmer settings, which can confuse users if not checked carefully.
Cons: The boiler’s controls limit hot water temperature, so tap flow adjustment may still be needed for comfort.

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Faqs

How do I switch the Potterton Promax Ultra Combi 28 between summer, winter, and heating-only modes?

Use the mode control to select the operating setting that matches your needs. Summer mode provides hot water only, winter mode gives both hot water and central heating, and heating-only mode keeps central heating active without domestic hot water demand. The controls may need to be pressed firmly for a few seconds before the display changes, so do not tap them lightly. If your heating or hot water is not working as expected, check that the correct mode is selected first.

What should I do if the boiler is not giving hot water or central heating?

Start with the basics: confirm the boiler is powered on, the correct mode is selected, and any external programmer or room thermostat is set to call for heat. The guide also points out that heating or hot water problems can come from thermostat settings, especially if either function has been switched off in the schedule. If the display shows an error or the system still does not respond, review the boiler mode, temperature settings, and any resettable fault indication on the screen.

How do I adjust the domestic hot water temperature on a Potterton Promax Ultra Combi 28?

Use the domestic hot water temperature control to raise or lower the hot water setting. The boiler limits the maximum domestic hot water temperature to 65°C, although the exact tap temperature can still vary with flow rate and seasonal water conditions. A lower flow rate usually gives hotter water, while a higher flow rate can reduce the temperature. If the hot water feels too cool or too hot, make small adjustments and then test a tap before changing it again.

How do I set the central heating temperature for better comfort and efficiency?

The central heating temperature can be adjusted with the boiler’s CH control to suit the home and reduce wasted energy. A lower setting may be enough in mild weather, while colder conditions may require more heat. The guide also recommends adjusting individual radiator temperatures where possible, so each room can be set more appropriately. That approach can improve comfort and help keep energy bills under control without overheating unused areas of the property.

What does the frost protection feature do on the Potterton Promax Ultra Combi 28?

The boiler has built-in frost protection that can operate in summer, winter, heating-only, and standby modes. If the water temperature drops below 5°C, the boiler will switch on automatically and run until the water has warmed enough to reduce freeze risk. This feature only works when the boiler has mains power available, so the power supply should remain on during cold weather. It is a useful safeguard when the property may be unoccupied or only lightly heated.

How do I use the boost function for temporary extra heating or hot water?

The boost function gives a short burst of extra heating or hot water without changing the full programme. Pressing boost once typically adds one hour, pressing it twice extends it to two hours, and pressing it again cancels the boost and returns the system to its normal schedule. This is useful when you want extra comfort quickly, such as before showering or arriving home early. After the boost period ends, the boiler goes back to the programmed settings automatically.

What do the display symbols on the boiler mean?

The display is designed to show the boiler’s operating status, including whether domestic hot water is requested, central heating is active, the burner is lit, or a fault is present. It can also indicate low water pressure, service due, standby, reset, and navigation through programming settings. If the screen shows an error, the symbol helps identify whether it is a resettable fault or one that needs further attention. Checking the display first can save time when troubleshooting.

What are the first troubleshooting checks if the boiler still will not fire up?

If the boiler does not start, check that the mode knob is not left on boiler off and that the required heating mode is selected. Next, confirm the hot water and central heating temperature controls are not turned down too far, the taps are closed, and external controls such as the programmer and room thermostat are switched on. If the display shows a fault, note whether it is resettable or linked to low pressure, then review the system status before trying a reset.