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  1. #1
    Join Date
    Feb 2013
    Posts
    1,006

    Default Calorifier problems

    i offer this to the collective wisdom in case I have missed the obvious.

    My calorifer has an electric heater and a feed from the engine.

    Both work well, or did.

    The electric hearter is fine, and still fine. The engine feed was fine was qucik and efficient at produucing a tank of hot water. However, the engine feed can now be swaped between the engine and a Hydronic heat source.

    Neither source now heats the water. All the evidence is both are producing hot water, which is flowing through the calorifier, but the heat is not now being transferred to the water. Whether the Hydronic or the engine is selected the water flows through the pipes, is hot, but the run flow also remains hot. I think the flow is good.

    One thought was an air lock - but this does not seem to be the case. The other thought is limescale, but odd this should suddenly have become a problem given it wasnt a problem literally a few weeks before the hydronic was installed.

    A possibility it seems to me is to run some Fernox DS-3 through the calorifier or equivalent which might shift any scale in case this is the source of the problem? I am thinking that as long as the pump is turned off and a hot water tap left open any pressure build up from CO2 will force water or gas out of the tap so there isnt any danger from over pressurising the cylinder. I assume IF there is a lot of scale there is a risk the cyliner could "spring a leak" but assume this should be a pretty small risk.

    The system by design does not use an accumulator, water is pumped into the Calorifier by a ressure activated pump. This has always worked very well, and still does. There is very good pressure to the hot water supply and very good water flow.

    Any brain waves much appreciated.

  2. #2
    Join Date
    Nov 2009
    Location
    Home UK Midlands / Boat Croatia
    Posts
    21,398

    Default Re: Calorifier problems

    I've no idea what this Hydronic is .... but I know about engine heating. You need to run the engine until it's up to temp and feel the hoses from and to the engine and the calorifier where they enter the calorifier coil. The one going in should be very hot (usually the lower connection and probably too hot to grip) and the one coming out should be either similarly hot or slightly cooler depending upon how long the engine has been running.

    If the hose coming out is much cooler and stays like that, then there is a circulation problem, (air-lock, blockage, incorrect routing). If the hose coming out is hot (too hot to hold your hand around once the engine has been running for 30 minutes) then there is something wrong inside the calorifier (scale) but that seems extremely unlikely.

    Richard

  3. #3
    Join Date
    Feb 2008
    Location
    Farndon
    Posts
    3,164

    Default Re: Calorifier problems

    Could be valves have been closed preventing flow through the heating coil ?@

  4. #4
    Join Date
    Apr 2018
    Location
    Mooring, Faro
    Posts
    1,992

    Default Re: Calorifier problems

    The normal way is to have a twin coil calorifier, one coil for the engine circuit and the other for the Hydronic. Your problem could no doubt be solved by inserting a cut-off valve to each circuit which are most likely joined together at the moment so you can select whichever you want to use.

  5. #5
    Join Date
    Feb 2009
    Location
    Greece (Aegean)
    Posts
    2,787

    Default Re: Calorifier problems

    If the tank is full of water and you haven't suddenly insulated the heating pipe then heat must flow from the hot side to the cold side and heat the water. Slow build up of something inside the coil isn't likely as you say that the loss of heating is a recent change after altering the system. OP's tank sounds fine as the electric element still heats the water.

    According to OP the heat sources (engine and hydronic) are producing heat and that isn't unexpected. OP says that heating coil inlet and outlet are both hot. Lack of flow would seem to be the problem if OP means they are both equally hot and the tank never gets hot.

    I would expect the outlet side to be a lot cooler if there was an air lock or blockage in the coil.

    A cross connection between the outlet and inlet sides would explain this problem. Hot water from engine doesn't go through the coil but crosses over to the Hydronic and at least some leaks back through that system. Same situation when Hydronic is running and it crosses over to the engine circuit.

    I obviously have no information about how OP's pipework is configured. I simply tried to apply some logic to see what might explain the symptoms (if OP has described them accurately).

    My first question is usually "what has changed" when trying to diagnose any system fault. OP states that the fault began after connecting a Hydronic heating system to the same pipework used to heat the water tank. A crossover would appear to explain both coil inlet and outlet being hot with little transferred to the tank. It might be worth investigating the possibility of water flow by-passing the tank coil.

    Anyone spot anything I've missed? I was up late last night, early start today and probably not at my most lucid just now.
    Last edited by Mistroma; 15-11-19 at 01:04.

  6. #6
    Join Date
    Jun 2001
    Location
    UK East Coast
    Posts
    1,915

    Default Re: Calorifier problems

    Can you explain how "the engine feed can now be swaped between the engine and a Hydronic heat source." Is this by valves? How is the pipework connected?

    Www.solocoastalsailing.co.uk

  7. #7
    Join Date
    Jun 2001
    Location
    Corfu - mostly
    Posts
    5,415

    Default Re: Calorifier problems

    When my calorifier developed similar symptoms - worked with the immersion heater, but not with the engine - its heating coil turned out to be blocked with sludge. This came from a disintegrating cooling stack in the engine manifold. A warning that possibly saved the engine.

  8. #8
    Join Date
    Jul 2002
    Location
    Home: Kent. Boat: Chichester
    Posts
    43,819

    Default Re: Calorifier problems

    Quote Originally Posted by ip485 View Post
    i offer this to the collective wisdom in case I have missed the obvious.

    My calorifer has an electric heater and a feed from the engine.

    Both work well, or did.

    The electric hearter is fine, and still fine. The engine feed was fine was qucik and efficient at produucing a tank of hot water. However, the engine feed can now be swaped between the engine and a Hydronic heat source.


    Neither source now heats the water. All the evidence is both are producing hot water, which is flowing through the calorifier, but the heat is not now being transferred to the water. Whether the Hydronic or the engine is selected the water flows through the pipes, is hot, but the run flow also remains hot. I think the flow is good.

    One thought was an air lock - but this does not seem to be the case. The other thought is limescale, but odd this should suddenly have become a problem given it wasnt a problem literally a few weeks before the hydronic was installed.

    A possibility it seems to me is to run some Fernox DS-3 through the calorifier or equivalent which might shift any scale in case this is the source of the problem? I am thinking that as long as the pump is turned off and a hot water tap left open any pressure build up from CO2 will force water or gas out of the tap so there isnt any danger from over pressurising the cylinder. I assume IF there is a lot of scale there is a risk the cyliner could "spring a leak" but assume this should be a pretty small risk.

    The system by design does not use an accumulator, water is pumped into the Calorifier by a ressure activated pump. This has always worked very well, and still does. There is very good pressure to the hot water supply and very good water flow.


    Any brain waves much appreciated.
    If the pipework to and from the calorifier, especially the return pipework from it to the heat source, is hot then there is hot water flow but if the calorifier is not heating then the hot water flow is bypassing the heating coil. If the coil is blocked the return pipework will be cold.

    May be the plumbing is allowing a total bypass of the coil or each system, engine or hydronic system, is providing a bypass for the other. If the latter, eventually the whole lot will be heted by the other and the calorifier will heat up

    A sudden build up of scale within the calorifier preventing heat transfer to the water seems very unlikely, especially coinciding with the installation of the additional heating source
    Last edited by VicS; 15-11-19 at 09:28.

  9. #9
    Join Date
    Nov 2015
    Location
    Portsmouth
    Posts
    240

    Default Re: Calorifier problems

    One explanation which fits the symptoms is that the calorifier is full of air.

  10. #10
    Join Date
    May 2001
    Location
    UK East Coast
    Posts
    37,210

    Default Re: Calorifier problems

    Quote Originally Posted by scrambledegg View Post
    One explanation which fits the symptoms is that the calorifier is full of air.
    If it was full of air, the OP would only have had air coming out of the hot tap.

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