New to the Alde system

Winter camping


Building a vehicle

How do you operate the digital control panel?

User instructions for the digital control panel should be included with your vehicle, but Alde also provides a 4-page quick start guide.

>Digital control panel quick start guide

How do I get hot water without central heating?

Set the desired temperature to well below ambient on the digital control panel.

Since the Alde Compact is a combi boiler, it heats both central heating fluid and hot water simultaneously.

If the desired temperature is set ≈5 °C below ambient on the digital control panel, the central heating will cut out— the heating fluid will not be circulated to the convectors and the living space will not be warmed.

Hot water is still readily available and the central heating will still cut in if the ambient temperature drops below that desired.

How much hot water does the system produce?

The Alde Compact boilers uses a store of 8.4 litres of hot water at >50 °C. When mixed at the fixture to a usable 38 °C, this amounts to ≈12 litres of heated water every 30 mins. Cold water <10 °C will take longer to heat.

The Hot Water Boost function—the tap icon on the digital control panel—cuts out the central heating for 30 mins while another 8.4 litres of hot water is heated to >65 °C. This amounts to ≈15 litres of heated water, mixed. Assuming an average flow rate of 3 litres per minute, this gives ≈5 minutes of continuous heated water for showers.

This can also be used to kill Legionella bacteria if the system has been standing unused for a spell. (Legionella bacteria dies within 2 mins at 65 °C.)

The boiler can be coupled with the Sigmar Dual-Coil Marine Calorifier for pratically unlimited hot water.

As a point of reference, a typical instantaneous water heater will draw ≈40 A on 230 V mains, and that's without providing central heating.

How quickly should the living space warm up?

Varies greatly, depending on the interior and exterior temperature, the design of the heating circuit and insulation of the living space. How much power the boiler has available has an effect, from 1 kW to 8.7 kW. Generally the living space will reach room temperatures within the hour, similar to the warm up time in a household central heating system.

How do I get the best performance from the system in my vehicle?

Ensure the heating circuit is bled of air (it should be correctly filled using a genuine Alde 1900-811 service pump). Ensure that vents in the furniture are not blocked. Use the maximum power electric heating and gas heating (propane only). Take showers after the central heating has brought the living space up to temperature. Don't allow the temperature in the living space to drop below 10°C if out for the day/night.

Does my system have 2 or 3 kW electric heating?

Pre-2013 (manufacture date), UK-spec boilers were limited to 2 kW electric heating, whilst Scandia-spec boilers had 3 kW. Some UK vendors used Scandia-spec boilers, however. This is the max power only, the Alde Compact boilers can still be set to 1 or 2 kW electric heating at the touch of a button, if 230 V mains supply is a concern. In 2013 all new boilers were produced to Scandia spec.

Do I need to winterise my system?


Unless your vehicle is explicitly stated to be self-winterising, even if the central heating is left at 5°C over winter there may be chinks in the fresh water system that are insufficiently heated to prevent the freezing.

Can I operate my central heating while the fresh water is drained down?

Yes, you can operate the system as normal, even with fresh water drained down.

How much current does the heating system draw?

There are two mechanisms in the Alde Compact boilers that draw >0.1 A current from the vehicle battery. The exhaust fan venting waste gases (≈0.4 A), and the heating fluid being pumped around the circuit (≈0.2 A). So normal draw from the vehicle battery is between ≈0.2–0.6 A, including the control panel. Max draw is 1 A for approximately three seconds at system start-up.

Max draw from 230 V mains is ≈4.5 A on 1 (1 kW), ≈9 A on 2 (2.1 kW), and ≈14 A on 3 (3.2 kW).

How much gas should the heating system consume?

The two-stage burner in the Alde Compact boilers can consume up to 405 g/h (propane) or 460 g/h (butane) on full power.

The two-stage burner is intelligently controlled, however. The boiler will use 230 V mains in preference to LPG, for example, and will only fire on one stage of the gas burner to maintain fluid temperature.

Generally, when running on gas in the British climate, a 6 kg bottle of propane should last all weekend.

The exact amount of gas consumed will vary from one day to the next, from one vehicle to the next. The heating system design is only one of three major factors, the others being insulation and ambient temperate.

>Advice on system design

Propane or butane – what type of LPG (liquid petroleum gas) should I use?

Propane. Alde UK recommend the use of propane in all Alde systems within the UK.

The operating temperature ranges of propane and butane are different, and will impact performance even at mild temperatures. The gas in a smaller bottle will cool quicker as it is tapped than in a larger bottle, and bottles chilled overnight may not warm to operating temperature again during the day. Thus the size of a bottle and the temperature at which it's stored will also impact performance.

BS 5482 Part 1 states, "For butane cylinders, satisfactory service might not be obtained at temperatures of less than 10 °C; the most suitable temperature range is from 13 to 30 °C. For temperatures less than 13 °C, the use of propane should be considered."

Propane will operate down to -42 °C and is more suitable for the British climate.

Be aware that Campingaz (formerly Camping Gaz) is butane, and therefore not recommended for use in our systems.

Autogas is a blend of propane/butane, and the ratio varies greatly across Europe. UK Autogas is guaranteed 99% propane, so is recommended by Alde UK for refillable gas cylinder systems.

At what level should the fluid in the expansion tank be?

When the fluid is cold it should stand approximately 1 cm above the Min mark.

What type of fluid is the heating system filled with?

A 50:50 mix of ethylene glycol antifreeze and water.

Ethylene glycol (aka mono ethylene glycol, MEG, and ethanediol) antifreeze is also used in engine radiators, and is commonly available from fuel stations, car accessory shops and online retailers, concentrated or ready to use.

This antifreeze should contain corrosion inhibitor, aka supplemental coolant additive (SCA) that protections against corrosion for a period of time.

Do not mix antifreeze containing different corrosion inhibitors.

Water should be clean and fresh, preferably deionised.

>Alde UK recommend G13 Spec antifreeze

What general maintenance and consumables are there?

The vendor should provide a maintenance schedule, though the following can be assumed:

The heat transfer fluid is a consumable and will need replacing before its corrosion protection expires. Most UK OEMs use silicate-containing antifreeze with 2-year corrosion protection from new.

If in doubt, replace the heat transfer fluid after the first 2 years.

Seasonally inspect the boiler's flue hoses. Check that the hoses are still secured and undamaged, and that they're clear and free of obstruction. Contact your vendor if the hose is damaged.

When in constant use, completely drain and refill the fresh water system once a month.

Safety and emissions tests should be carried out in accordance with local regulations.

What is the power output of the Alde aluminium convectors?

The convectors put out ≈400 W per metre. Doubled up, they put out ≈600 W per metre.

Can copper parts be used in the heating circuit?


Copper particles will cause galvanic corrosion in the aluminium surfaces in the boiler's glycol cylinder.

The boiler's domestic hot water cylinder is stainless steel.

How much fluid is in the central heating system?

Varies. As a rough guide, most caravans and motorhomes hold 10–13 litres, boats 15–25 litres, portable cabins 18–22 litres.

How much does an Alde system weigh compared to a forced (blown) air system?

Varies. Bear in mind that even when the heating circuit is full, an Alde system provides both central heating and hot water, rather than having two separate systems. When full, an Alde system will weigh on average 3–7 kg more than a separate heating and hot water system, the equivalent of up to 3 bags of sugar.

What caravan and/or motorhome manufacturers currently fit Alde systems?

Alde systems are fitted into a wide range of models.

>Our European installed base

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