• Welcome to PlumbersForums.net - The international free plumbing advice forum. Professional plumbers sharing advice with fellow plumbers and DIY alike. Register for free today! - Checkout the Plumbing Advice forum and then our Plumbing Videos area which still needs populating.
  • If you central heating doesn't work, radiator isn't coming on, boiler wont come on, etc - then post a REPLY in this EXISTING THREAD My Central Heating Doesn't Work - Master Thread - Please aboid making new threads on this same subject.


A heat exchanger is a system used to transfer heat between two or more fluids. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum refineries, natural-gas processing, and sewage treatment. The classic example of a heat exchanger is found in an internal combustion engine in which a circulating fluid known as engine coolant flows through radiator coils and air flows past the coils, which cools the coolant and heats the incoming air. Another example is the heat sink, which is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant.

View More On Wikipedia.org
  1. E

    Snapped screws on heat exchanger require a whole replacement?

    We just had a service done on our Ideal ICOS boiler and were told that the 2 screws on the back of the heat exchanger have snapped off. It was marked as dangerous and has quoted a whole new heat exchanger as there are still bits of screws stuck inside that cannot be removed. For 2 broken screws...
  2. D

    Faulty heat exchanger

    Hi, Boiler is losing pressure, from 1.5 bar to 0 bar in about 4 hours. Have checked all rads and seem to be fine, no water out external prv pipe. If the heat exchanger is faulty what do I need to look for? There is a constant run of water from the condensate pipe when heating on but not sure...
  3. 50Cent

    Tiny leak from heat exchanger

    Hi everyone, I have taken out the heat exchanger because a tiny leak was found around the red gasket at the top of the heat exchanger of a Worcester Green Star 28i Junior. The gasket itself is in perfect condition with no cracks. As you can see from the photo, the rust is near that holding...
  4. G

    Multiple thermostats and heat exchanger question

    I have a thermal store heated by a boiler with its own thermostat. I also have a stove with a back boiler. The stove heats water in a separate tank. There is a thermostat on this second tank that pushes hot water over to the store tank when it's hot. It's a closed loop and goes through a heat...
  5. B

    Main heat exchanger overheating when heating off

    Hi All, Have a peculiar problem with my Gloworm Flexicom 30cx combi boiler, the main heat exchanger is getting red hot and fault coding on overheat even though the boiler and central heating is not on, i shut the boiler down for a while, clear the fault code and it will be fine again for...
  6. B

    Green star exchanger noise

    Green star oil combi heat exchanger noise day and night water whooshing /gurgling
  7. H

    Best way to clean a heat exchanger

    I have a central heating system in a 7yr old ‘Persimmons’ new build, that has several problems related to reduced flow. A nice retired engineer on these forums, has helped me, through extensive testing, identify the heat exchanger as the culprit. The boiler is a Glowworm Ultracom 24hxi, 10...
  8. R

    Baxi 105e plate heat exchanger upgrade

    Hi all New Diverter valve going in mid week ( subject to eng being available) and from my previous discussion, the dhw plate heat exchanger could also be causing the bypass to lift. So I have sourced a potential replacement dhw plate heat exchanger to go in at same time, but the original part...
  9. M

    What is this material in my Heat exchanger

    Main Eco Compact boiler installed 18 month ago, system power flushed immediately before and straight after boiler installation, Magfilter 2 and inline descaler installed at same time. Boiler has just failed with blocked plate heat exchanger on the DHW side, heat exchanger cleaned and everything...
  10. B

    Glow Worm Fuelsaver 40B Mk2 Heat Exchanger Kettling

    I have an old Glow Worm Fuelsaver 40B Mk 2 installed on the kitchen wall. In November, the heat exchanger began making a kettling noise. It’s done this before. In the past, simply draining and refilling the system to flush out loose deposits was enough to stop the noise. In November 2021, I...
  11. L

    Is a pool heat exchanger suitable for a communal heating system?

    Hello all and Merry Christmas, We are in the process of planning the replacement of our 50-year old heating boiler serving a residential block of 12 flats with a total of 60 radiators. It is a vented single-pipe heating system, which has not been properly maintained, and we only recently...
  12. A

    Small cracked heat exchanger really an immediate do-or-die-NOW problem?

    I wrestle trying to get my mind around the claimed dangers of a heat exchanger with a small crack in it. I know salesman LOVE it, as it is very convincing to homeowners, and since personal safety is implied, it's pretty much a "signed deal" for a new furnace. I believe I have so much evidence...
  13. C

    My grant 70 mk 2 heating pressure is constantly increasing in pressure. I have changed the heat exchanger as I believe that was the problem. Any ideas

    My grant 70 mk 2 heating pressure is constantly increasing in pressure. I have changed the heat exchanger as I believe that was the problem. Any ideas
  14. Atanas Peev

    Heat exchanger problem

    Hello everyone do any one had such experience with main heat exchanger on combi boiler Thank you
  15. G

    Power flush before blocked heat exchanger renewal ?

    Evening All We are having a new heat exchanger fitted to a Veissmann boiler, the boiler is only six months old, the installers carried out a power flush but only after the boiler had been running for about a fortnight, then after six months it failed to heat radiators to temperature. Viessmann...
  16. L

    Heat exchanger for new boiler on legacy open vent system

    Hi, We are planning to replace a 50-year old boiler for the communal heating-only (no hot water) of a residential block of 12 flats with 60 radiators. We have an open vent system. Our heating engineer recommends the GB162 100KW, WITHOUT a plate heat exchanger, because he says that heat...
  17. G

    Baxi duo tec 28 heat exchanger problem

    Our boiler went off with error 133. I investigated and found the ignitor module had melted! This was replaced. When the boiler fires up now there is intense and immediate heat radiation from the left upper and lower front side of the heat exchanger unit. I switched off immediately and have a...
  18. S

    URGENT Hi have a potterton performa 24he hot water flow is very slow. Have changed plate heat exchanger and made no difference any ideas?

    Hi have a potterton performa 24 he hot water flow is very slow. Have changed plate heat exchanger and made no difference heating is fine any ideas?
  19. T

    Heat Exchanger

    We suspect that we might need a new heat exchanger for our boiler which is a Vaillant ecoTec plus 428. Can anybody who has experience with this type of boiler tell me how easy it would be for a Heating Engineer to confirm that this is our problem? Also, if it needs to be replaced, what would be...
  20. V

    Any clever ideas for cleaning soot blockage from Grant Condensing Heat Exchanger?

    Anyone got any suggestion on how, if possible you could clear soot from the condensing heat exchanger of a Grant Vortex. Have many of you encountered blockages like this? Have any of you been able to avoid condemnation of the boiler the due to the stainless heat exchanger being blocked? What can...
Creating content since 2001. Untold Media.