Commercial Boiler Maintenance


Regular commercial boiler maintenance is the most effective and economical way to ensure that they always operate optimally, and to ensure that they last as long as possible. Due to their size and technical characteristics, any problem with a commercial boiler can be costly, and this can be made even worse by having to replace parts that have deteriorated due to lack of maintenance. In this article, you will learn why it is so important for commercial boilers to receive preventative maintenance, how often this should be done, how to create a technical report and a maintenance plan for this kind of boiler, and about technical maintenance for commercial boilers in Spain.

The Importance of Preventative Maintenance for Commercial Boilers

According to a technical report from the German company, BOSCH, many commercial and industrial companies in all sectors use boilers: the food and beverage industry, the textile industry, hospitals, heating, air conditioning, large scale cooking, the building materials industry, the paper industry, the chemical industry, the pharmaceutical industry, and many others.

Boilers are the backbone of many 21st century companies as they are inexpensive and have become increasingly efficient and profitable. It is for this reason that technical maintenance services and boiler spare parts will continue to be a highly important economic sector.

Generally speaking, there are 3 types of boiler maintenance: preventative maintenance, predictive maintenance, and corrective maintenance.

Preventative maintenance is typically the cheapest of the three, although it can appear to be the least necessary. Technically, when a piece of equipment only requires maintenance, this is because it doesn’t have any obvious faults. This can result in overconfidence on the part of boiler owners. The truth is that it is always necessary to carry out regular preventative maintenance because:

  • It is mandatory as the law states that boilers must be maintained regularly even if they do not have any specific problems.
  • It is safer for the health of employees and the company’s working environment. Without regular maintenance, boilers can break down and, in some cases, explode and cause human and material loss.
  • It is more cost-effective as it allows the detection of potential breakdowns before they occur, thereby avoiding the need to compromise production continuity.

Despite this, there are still companies that practically never carry out preventative maintenance on their boilers. They only request technical assistance when there is an unexpected breakdown or a failure that is interrupting normal production. This is not good practice. In the long run, corrective maintenance is more costly than preventive or predictive maintenance as corrective maintenance often requires replacement parts (or replacing entire units).


Why preventive maintenance is less costly than corrective maintenance

Preventive maintenance should actually be done on a daily basis. Its goal is to correct malfunctions on the fly, prevent boiler breakdowns without interrupting production, and extend the life of the unit. Corrective maintenance, on the other hand, involves breakdowns that have occurred unexpectedly. This results in additional costs, sometimes for importing spare parts, and sometimes having to replace entire components that have malfunctioned due to overworking resulting from lack of preventive or predictive maintenance.

In many cases, the cost of repairs is higher than that for simple routine maintenance. In addition, when corrective maintenance is conducted, the company’s production often has to come to a halt, resulting in loss of profits which could have paid for the repair costs.

The Importance of Using Professional Boiler Technicians

An engineer or technician working for a boiler maintenance or spare parts company can tell you how often you should carry out preventive maintenance on your boiler. They can also help you to optimize maintenance costs when conducting periodic boiler inspections.

As is the case with all equipment, preventive maintenance by qualified professionals means that you are investing the least amount of money in your machinery because:

  • It allows you to keep your boiler operating without unexpected interruptions
  • It enables you to plan your boiler’s maintenance according to its actual needs
  • There is no halt in production and no consequent economic loss as maintenance can be done: – Outside of working hours

– During your production’s quiet season

– By covering operations with another boiler

  • It allows you to avoid substitutions of spare parts before they become completed damaged and prevents you having to wait for the spares to be imported and spending money for extra fast shipping (since spare parts are normally not manufactured in Spain, and the shipping cost can be quite significant when you need it urgently).

How Often Should a Commercial Boiler Be Serviced?

How often your boiler needs to be serviced depends on the parts and functions that need to be checked. It also depends on the boiler’s level of use. Boilers that operate a third of the day at medium capacity do not require as much maintenance as those that operate at almost full capacity all the time.

Depending on the stress your boiler is put under, there may be operational functions and components that need daily review and maintenance. Some boilers can function perfectly fine with only annual maintenance, while others need inspections somewhere in between. It is for this reason that commercial boiler maintenance has 5 frequencies:

  • Daily maintenance
  • Weekly maintenance
  • Semi-annual maintenance
  • Annual maintenance
  • Five-year maintenance

What Boiler Aspects are Checked at Each Maintenance Interval?

Below we will briefly outline which parameters, functions and parts should be serviced at each of these intervals:

  • Daily maintenance. Routine daily maintenance can be carried out by employees. It is rare that you would need to call in a technician to perform daily maintenance. This type of routine maintenance involves activities such as:

-Checking the water and combustion levels

-Bleeding of the boiler

-Water treatment according to a pre-established plan

-Check the ratio of the pressure, water, temperature and gas combustion, vapor pressure, etc.

  • Weekly maintenance. Boiler functions such as the correct closing of fuel valves, properly operating air and fuel connections, lighting systems for alarms, safety connections, leaks, vibrations, unusual noises, etc should all be checked.
  • Semi-annual maintenance. This involves checking refractory and electrical components, cleaning the water level gauge, checking the oil pump, checking the air purifier, aligning the compressor, etc.
  • Annual maintenance. This requires checking inside the boiler casing, clearing out the smoke vents, and inspecting the water chamber.
  • Five-year maintenance. This is a long-term operational review (similar to a boiler hydraulic test), and not all boiler maintenance companies offer this service.

Suner shows you how to create a technical report for commercial boilers


The purpose of creating a technical report is to clearly establish all the points that must be looked at when the boiler is being serviced. Data is obtained by measuring various functional parameters while the boiler is operating, measuring combustion efficiency, and checking the boiler’s general condition.

In addition to the above points that should be checked, the technician should also keep a detailed history of how the boiler is working and its operational measurements. This allows a balanced viewpoint and helps to diagnose any problems with boiler efficiency, how the parts are working, which ones are worn out, which ones need to be repaired, or even which parts should be replaced.

To ensure the accuracy of the measurements taken and information collected, the technical report should include measurements taken with traditional or high-tech devices, graphs, tables, photos, videos, and any other tools to help record accurate data before maintenance is carried out.

The following parameters and reviews should be included in the technical report for maintenance purposes:

  • Internal inspection of the pressure gauge, burner, plates, and pipes for signs of corrosion or rust.
  • Take an ultrasound measurement to determine the thickness of the plates, burner, and cylindrical body, and record all values.
  • Check the floats and the electromagnetic meters to determine if they are giving accurate readings.
  • Check how well the cables are insulated.
  • Perform a hydraulic test on the unit with its normal working pressure, and record all findings.
  • Check the internal condition of the burner, cables, and connection cards.
  • Analyze the combustion levels, gas temperature in the chimney, and the boiler’s thermal performance.
  • There are, of course, other elements that should always be checked over by a professional.

Format and structure of technical reports for boiler maintenance

A technical report gives an opinion or diagnosis on a boiler’s current state. It serves as a foundation and guide throughout the maintenance process. The structure of a technical report for boiler maintenance should reflect everything in writing and in an organized way. It should describe the following aspect to make the work of maintenance technicians easier:

  • Assessment of the boiler’s general condition
  • Values collected as a result of various tests and measurements
  • Problems that need to be solved immediately
  • Issues that could be postponed as they are not relevant
  • Components that are functioning well
  • Parts that require regular maintenance
  • Components that need to be repaired
  • Parts that must be calibrated
  • Components that need to be replaced by new ones
  • Boiler aspects that don’t comply with what is set out by the manufacturer
  • Boiler aspects that could not be measured
  • Possible risks and safety issues
  • Status of the chimney and other gas evacuation parts

Spreadsheet templates are available that help with collecting this information.


Suner’s commercial boiler maintenance plan

If effective, a commercial boiler maintenance plan covers all short, medium, and long-term evaluations. Its aim is to ensure that the boiler operates optimally, there are minimal expenses in terms of repairs or spare parts replacements, worker and facility safety is optimal, fuel is used correctly to prevent contamination, the unit is chemically cleaned to extend its useful life, and there is a plan to prevent unexpected production interruptions.

Daily routine maintenance should be carried out by all company employees who come into direct contact with the boiler. Of course, monthly, semi-annual, annual, and five-year maintenance should be performed by specialized companies. Suner offers you an effective maintenance plan for commercial gas or diesel boilers. This maintenance plan includes the following evaluations with monthly, semi-annual, annual, and five-year frequency:

Monthly maintenance by Suner

  • Fuel consumption controls
  • Electrical energy consumption controls
  • Water controls
  • Inspection of control and safety elements
  • Checking pipes and door seals
  • Ignition circuit inspection
  • Boiler-burner closure checking
  • Gas or diesel filter cleaning
  • Measurement of fuel flow in relation to the boiler’s power
  • Pressure check in the gas or diesel line
  • Checking the tightness in the gas lines and the operation of leak checks greater than 100kW
  • Diesel line and solenoid valve tightness check
  • Gas release circuit review
  • Checking of operational sequence

Semi-annual maintenance with Suner

(This should be carried out twice, at the beginning and end of the season).

  • Cleaning the boiler’s gas evacuation circuit
  • Checking of refractory material

Annual Maintenance with Suner

  • Electrical panel and boiler lines review
  • Control device inspection (thermometers, pressure gauges, etc)
  • Boiler insulation check
  • Checking of and cleaning the chimney and gas ducts
  • Inspecting and setting the safety valves

Five-year maintenance with Suner

  • Carrying out of a hydraulic test on the boiler

Technical maintenance services for commercial boilers in Spain

Boilers have always been commonly used in Spain in both the commercial and domestic sectors. As a result, our country has a broad range of boiler maintenance companies. Among them, Suner stands out as a leading company for boiler and burner spare parts and maintenance.

Learn about the different kinds of commercial boilers

Our company has over 40 years of experience in the boiler and burner maintenance sector. We have satisfied 14,000 happy customers in over 30 countries. Suner can offer you information on specialized maintenance to make maintaining your commercial boilers easier and to provide you with all the spare parts that you need.


We have the top brands in the industry, with a stock of over 30,000 original references. We offer you excellent service and guarantee all our spare parts replacements to ensure that your equipment operates optimally in a fuel-efficient way. Give us a try.

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