Heat Exchangers – Frequently Asked Questions & Answers

Heat exchangers can be complicated and complex pieces of equipment. We have compiled a list of frequently asked questions that have come from work we’ve done over the years. Hopefully, our answers to these questions will help you take the correct course of action for your heat exchanger, whether it be a service, repair or replacement.

If you have any questions you don’t see below, please contact us and we will be more than happy to help.

How much does it cost to repair a heat exchanger?

This could range from £100 to £1,000,000. This first question is really difficult to answer because every type of repair is different. It’s a case of ‘how long is a piece of string’. The things to take into consideration are:

  1. The type of damage to the heat exchanger
  2. The extent of the damage to the heat exchanger
  3. The cost of the parts required to repair the heat exchanger
  4. The cost of the labour required to perform the repair

What you need to consider before repairing your heat exchanger

Sometimes a repair might be more expensive than a replacement. Therefore if your heat exchanger breaks down, you should consider the following…

Heat Exchangers Repaired and Back in Use1. How old is your heat exchanger?

Depending on the type of heat exchanger, if it is older than, let’s say 10 years, it may be worth considering a replacement. Getting it repaired might just be papering over the cracks. If your heat exchanger is relatively new, then a repair is probably the way to go unless there is a major, irreparable problem with it.

2. How is your heat exchanger performing?

If you find that your heat exchanger is not performing well under normal function, again you may want to consider a replacement. It might not be worth paying for the repair. To assess the performance of your heat exchanger we can perform a number of tests. For example, a pressure test to see if there are any leaks; a flow-rate test to see if there are any blockages; an ultrasonic test to check the wear of the tube material.

3. How often does your heat exchanger break down?

If your heat exchanger continually breaks down, again you might want to assess whether it’s worth repairing or whether you should just replace it.

What you should do next…

Get in touch with us and before you take any action, we can provide full testing, analysis and recommendations. We will carry out a full inspection and, where required, pressure, flow-rate and ultrasonic testing to establish the scale of the damage to your heat exchanger.

How long do heat exchangers last?

A heat exchangers lifespan depends on a number of factors. A typical heat exchanger should last for around 10 years in full working order. However, this depends on the following factors:

  • How often you have your heat exchanger cleaned
  • The working environment where your heat exchanger is in use
  • Whether your heat exchanger is being used for it’s original purpose
  • How often your heat exchanger breaks down
  • The amount of strain your heat exchanger is under

A well designed heat exchanger working in a suitable environment will last for many years. However if the unit is working in an environment that it is not suited to, or originally designed for, it can fail in a short period of time.

What happens when a heat exchanger fails?

Heat exchangers can break down for a variety of reasons. These can include blockages, corrosion, erosion or leakages. These types of problems can result in poor performance or, in the worst case scenario, a complete breakdown.

Below are the most common reasons for a heat exchanger breakdown.

Heat Exchanger Repair - Unblocking a Shell & Tube Heat Exchanger

Unblocking a turbine condenser heat exchanger using rotating brushes and water feed to remove debris

Reason for breakdown: blocked heat exchanger

A heat exchanger can easily get blocked due to mineral deposits coming from the water, or oil which carbonises and causes a build up in the tubes. In most cases you would see a gradual decline in the performance of your heat exchanger, meaning reduced efficiency.

How we deal with a heat exchanger blockage

Firstly we will perform tests to diagnose the issue. For example, we would perform a flow-rate test to see how much water is passing through your heat exchanger. If this result is poor, it usually indicates a blockage. If that’s the case, we would then go about finding the blockage and clearing it, as well as trying to identify the root cause of the issue. This work can be carried out on your premises/vessel or we can take your unit away and do the work at our base in Sheffield.

Click on the YouTube video below to see an example of how AKS deal with a blocked heat exchanger. (You may need to accept YouTube’s privacy terms to view the video).

I Accept

Reason for failure: corroded/eroded heat exchanger

Another common reason why a heat exchanger may fail is due to corroded or eroded parts. A heat exchanger works hard to move substances such as oil or water from one place to another. Therefore erosion and corrosion are commonplace after a period of time.

How we deal with heat exchanger corrosion and erosion

Following an initial inspection and diagnosis, we would identify the corroded or eroded tubes and replace them. This is the most cost-effective way to deal with this issue. We provide a variety of tubes to suit all types of heat exchangers, in materials such as cupro-nickel and copper.

Reason for failure: leaking heat exchanger

A leaking heat exchanger is an inefficient heat exchanger or, in some cases, a broken one. Your heat exchanger needs to operate at a certain pressure level in order to do its job correctly, so inevitably a leak can cause problems.

How we deal with heat exchanger corrosion and erosion

We can identify a leak using pressure testing. We use a hydraulic pump with calibrated gauges to test the pressure levels of your heat exchanger. Once we find the root and location of the problem, we either repair or replace that particular part, leaving your heat exchanger in full working order.

How often should a heat exchanger be cleaned?

It is good working practice to service, inspect and clean your heat exchangers every 12 months. However subject to the working conditions, this may be every 24 months.

Each system is different and it is important that you identify the cleaning period for your heat exchanger to ensure continued efficient performance. If you are in any doubt, please contact a specialist who can help you with this.

How often should heat exchanger tubes be replaced?

This completely depends on the working environment of the heat exchanger.

If the unit is working in a corrosive environment, such as in sea (salt) water, or if the materials used to build it have not been selected correctly, then replacement could be a matter of weeks or months.

A well designed heat exchanger with good material selection can result in many years of working life before tubes require to be changed.

Heat Exchanger in Need of a Retube

Here is a complete list of the factors that can affect the lifespan of your heat exchanger tubes:

  • Working environment
  • Exposure to corrosion (ie salt water)
  • Materials used to manufacture
  • Frequency of use
  • Workload
  • Frequency of cleaning & maintenance
  • Quality of workmanship
  • Working efficiency

What if my heat exchanger needs to be replaced?

If the worst case scenario occurs and your heat exchanger needs to be replaced, you still have a number of options. Before replacing a heat exchanger, we will always do our best to repair it. However in some cases, it is more cost-efficient to simply replace it altogether.

Options when replacing a heat exchanger:

  1. Replace with a like-for-like, identical original unit – the most common-sense way to replace your heat exchanger.
  2. Use an alternative supply replacement unit – if you can find a like-for-like replacement, we could source or manufacture one.
  3. Use an upgraded unit – you may take the opportunity to improve your system by making an upgrade

How much does a new heat exchanger cost?

Again this is difficult to answer. It could range from £100 to £1,000,000, depending on the unit. There is no way to estimate this without performing a survey first.

The questions and answers above apply to the following types of units…

…however if you have questions about anything not mentioned, please contact us.