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Location of Calorifiers

Hi Guys, I'm trying design the layout of a narrowboat as I would like to buy a sailaway and fit it out myself. I would like to place the Calorifier under the fixed inline double berth MIDSHIP! - which will be approx 15-18 foot from the engine. Would this cause a problem being so far from the engine? And if so, is there a solution, such as an extra pump to speed up the flow of water from the engine and, therefore, lessen the loss of heat? Thanks Cindy

Asked by: C Holton  | 1.02am, Friday 18 August

WW says:

Hi Cindy,
Locating the calorifier under the bed midships won't be much of a problem- the length of pipework isn't too much of an issue- however you will need to check the manual for the particular engine you are fitting. It may be than an additional header tank is required, to cope with the increased volume of coolant (particularly when it expands). The size of the header tank will need to be determined by the volume of liquid in the whole system- if the skin tanks are chunky rather than thin, you may already have too much coolant space. It is almost impossible to fit an additional cooling pump, as the thermostat on the engine would cause conflict when closed (and probably damaged the auxillary pump) as most of the small engines fitted to inland boats are not designed to be fitted with such a pump. You won't loose much thermal load from the pipework and that which does might both help air circulation where they pass through (by warming lockers, etc.) and also any additional heat drawn from the engine is a good idea when cruising, as skin-tank cooled engines are prone to overheating on rivers, if installed incorrectly (often with too small and a badly designed cooling tank(s)). Skin tank design is often overlooked by boatbuilders, yet engine manufacturers are quite stringent about how they are to be constructed (and many boatbuilders fail to actually read the manual!).
Also, the coil inside a calorifier doesn't actually transfer a great deal of thermal load- around 600 to 1000W maximum; a 40hp engine at tickover is generating around 7kW of thermal loading; so any loss of thermal load will be negligible in performance of the calorifier.
Note that a horizontal calorifier is usually somewhat less efficient than a vertical one, as there is a greater contact between the lower cold layer and upper heated layer, once hot water is drawn off, in a horizontal calorifier.
An alternative, would be to use a plate heat exchanger (Alde make one as an "off the shelf" fit) which could be used to act as an intermediary- however, these are more usefully fitted into the calorifier return pipework and plumbed into the central heating circuit (and fitted before any boiler) so that when cruising, once the calorifier is warmed up, any additional "waste" thermal load is passed into the central heating circuit, rather than just dumped into the canal. We have provided more information on how to do this in the magazine in the last couple of years.
Hope that helps- please contact us if we can be of any more help.

Mark Langley  | 9.57AM, Friday 18 August

Hi Cindy,
If we can help- please let us know- its what we are here to do :)

Mark Langley  | 12.06PM, Friday 18 August

Readers say:

Mark, what a fab and easy to understand answer - Thanks very much. When funds become available I'm will be buying a nb in the mean time I'm just doing homework to find out the difference in cost between a sailaway (and fitting out myself) and a 2nd hand boat that I would have to adapt for my purposes! I don't want to underestimate the budget so going in to a lot of detail at this stage! (It keeps me out of mischief!!) Thanks again, Cindy

C Holton  | 11.12AM, Friday 18 August

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