Central Heating System Leaks – The Leak Sealant Dilemma

Winter is fast approaching and you wake up one morning to find that mysteriously, your heating hasn’t come on like it normally does. Chilly and curious, you tiptoe downstairs and across the cold floor to the boiler cupboard to see what’s going on and you discover the boiler pressure is at zero.

Fast forward a week or two, including several hours spent Googling all sorts of central heating problems including ‘How to re-pressurise my boiler’ or ‘Why is my boiler losing pressure?’ a couple of visits from boiler engineers and plumbers, and lots of time sat at home feeling cold, and you finally come to the realisation that you heave a leak on your central heating system pipework!

Hopefully it won’t be too much longer before you find yourself on the phone to one of ADI’s Central Heating Leak Detection advisors to book a non-invasive leak detection to find your leak.leak detection company

As you may have read in some of our other blogs (or as you may already know from speaking with us), when you call us we will ask you several questions about your heating system and boiler pressure loss rate. Your answers will help us to gauge the size of your leak and what our chances finding it will be – we want to do everything we can to spot any potential red flags and make sure your money is well spent!

One of the things we ask about is whether any leak seal chemical has been used to try and resolve the leak. This is because leak sealant can significantly impede the testing process and drastically reduce our chances of success in locating your leak.

In case you’re thinking you’ve just found the solution to your leak, please don’t be fooled! From our experience, leak sealant is generally not a reliable solution for curing leaks for a number of reasons:

  1. About half of the people who contact us for help with finding a leak have already tried it… Logically this must imply that it doesn’t work because if it did… there would be no need for them to contact us!
  2. It can invalidate the warranty on your boiler.
  3. It impedes our most effective method of leak detection – tracer gas testing.

In addition to thermal imaging, we also use tracer gas testing to locate leaks on heating systems. This involves draining all the water out of the heating system and re-filling it with a harmless combination of hydrogen and nitrogen tracer gases. The gases then find the leak, escape from the damaged pipe, and are light enough to rise up through any porous floor material. We use special hydrogen sensing equipment to detect where the gases are rising, and that’s what gives us the location of the leak!

We are not 100% sure about the science behind it, but from our experience, if there is leak seal chemical in the heating system, this can render our tracer gas testing completely ineffective. In the worst case scenario, the leak will become blocked at the time of testing, the system will hold its pressure, no tracer gases will be able to escape and the leak remains completely unidentifiable.

The result: one very frustrated Central Heating Leak Detection engineer – and even worse – one very unhappy customer!

The Solution

In general, if leak sealant has been used in recent months, we will advise removing any leak seal chemical from the heating system prior to booking your leak detection appointment. We recommend seeking the advice from a trusted plumber on how to do this. Your two main options are having the system power flushed or using a chemical cleaner. We do emphasise the importance of getting a plumber to assist you with this, as both options have certain implications for the health of your heating system and one option may suit your heating system better than the other.

Whether you choose to take this advice is entirely up to you. Some lucky people choose to leave the sealant in the system and proceed with the appointment anyway, it’s possible the leak will still be found. This is particularly true with large leaks in solid concrete floors – where thermal imaging and damp meter testing are still very effective.

If you are unsure, call 0800 731 3843 and a member of our team will be delighted to give you some advice, tailored to your specific situation.