Answers to some of the most frequently asked questions.

An oil boiler should be serviced once a year by an a certified heating engineer. Regular servicing ensures the boiler is operating safely, efficiently, and within warranty requirements. Servicing requirements can be found in the oil boiler manual.

Low boiler pressure is often caused by a leak in the system, bleeding radiators, or a faulty pressure relief valve. Here’s what you can do:

1. Check the pressure gauge (usually on the front of the boiler). If it’s below 1 bar, it’s too low.

2. Look for visible leaks around pipes and radiators.

3. Use the filling loop to slowly top up the pressure until it reaches around 1.5 bar. Note: Topping up the pressure should be completed in conjunction with the boiler manual and with the system cold.

4. If the pressure drops again soon after topping up, call a qualified engineer, as there may be a hidden issue.

Never ignore persistent pressure loss—it can lead to more serious damage.

A non-starting boiler could have a simple fix. Check the following:

Power supply: Ensure the boiler is plugged in and the fuse hasn’t blown.

Oil level: Make sure there’s enough oil in the tank.

Thermostat: Set it higher than the room temperature.

Programmer or timer: Check that it's set to 'on' or 'heating'.

If the boiler locks out again after a reset, it’s best to call a heating engineer to avoid causing further damage.

If your radiators are hot but you’re not getting hot water, it might be:

A faulty diverter valve (responsible for switching between heating and hot water)

Incorrect timer or thermostat settings

A sensor failure in the hot water cylinder

Limescale build-up affecting flow or temperature sensors

Try adjusting your controls first. If that doesn’t help, you’ll need an engineer to diagnose the internal components.

Your boiler warranty information & terms can be found in the product manual.

Registration is quick and can be done online via the Warmflow Connect Platform.

You’ll need:

Product model and serial number

Installation date

Installer’s details (must be certified)

Your contact information

Our Technical Support Team is here to help. You can:

Call us on 028 9262 1515

Or speak to your installer or service engineer for urgent issues

Have your product details (model, serial number, and installation date) ready when you get in touch—it helps us provide faster assistance.

Although air source heat pumps require less maintenance than traditional systems, regular upkeep ensures peak efficiency. Here's what to do:

Every month: Check that the external unit is clear of leaves, snow, or debris.

Annually: Schedule a professional service to inspect refrigerant levels, electrical connections, and system pressures.

Also, monitor performance—unusual noise or reduced output may signal a problem. Keeping the area around your heat pump clear helps airflow and improves performance.

Most homes can use a heat pump, but to maximize efficiency, some upgrades may be needed:

Good insulation is essential. Without it, the heat generated may escape quickly.

Larger radiators or underfloor heating can help distribute lower-temperature heat more effectively.

A heat loss survey is highly recommended before installation to determine if upgrades are necessary. Warmflow or a certified installer can help assess your home's suitability.

No, this is usually steam from the defrost cycle and is normal.

With annual servicing and maintenance, approximately 12-15 years.

Depends on heat demand and property heat loss.

Possible factors:

Heat pumps are designed to run continuously rather than in short bursts like boilers.

Most systems have two modes:

Comfort mode: Maintains a comfortable temperature when at home.

Setback mode: Typically 3-4°C lower for periods when away or at night.

Consider setback mode as the "off" mode—this prevents excessive reheating and reduces energy consumption.

Keeping all rooms consistently heated rather than shutting off areas can lower costs.