jadwhite
New Member
I have bought a small (10 Litre) calorifier for my boat but I'm not sure of the best place to install it. I'm sure that later 281's had hot water, does anyone know where the calorifier was installed on these?
Calorifier for Beneteau Oceanis 281
- Thread starter jadwhite
- Start date
nimbusgb
Well-Known Member
What matters is where it will fit on your boat. On my Oceanis 390 its in front of the semi bulkhead that forms the galley partition, underneath the saloon settee. Same area now has fridge compressor and shower sump pumps.
Fit it as close to the engine as practical if you are using engine water heating. Otherwise as close to the required outlets as practical.
It doesn't need to be 'got at' frequently but the element may need to be removed / replaced. The safety valve may need checking and an overflow/expansion releife may need to be vented to the bilge.
Apart from that it will need to be plumbed in to the cold water circuit.
Fit it as close to the engine as practical if you are using engine water heating. Otherwise as close to the required outlets as practical.
It doesn't need to be 'got at' frequently but the element may need to be removed / replaced. The safety valve may need checking and an overflow/expansion releife may need to be vented to the bilge.
Apart from that it will need to be plumbed in to the cold water circuit.
alan17
Well-Known Member
I was advised by the builders of my yacht to install calorifier as low as possible.
John100156
Well-Known Member
Don’t know about your boat - but other than physical constraints and close proximity to outlets or primary engine heating circuit (as previously said); in my opinion there is no major benefit regarding mounting high/low, assuming you use a cold water pump to pressurise the cold water to your taps and into the bottom of the calorifier. The secondary (HW) system is self venting once you open up a tap!
Some other tips:
1) Take HW from top of calorifier.
2) Cold feed to bottom.
3) Install a small expansion cylinder into the HW system (just after the water pump) or at another convenient location to allow for HW expansion.
4) Install a pressure relief valve to the calorifier secondary (HW) side, to release water into the bilges. Select discharge position carefully though as it's likely to be a hot discharge!
5) Install, electrically in series with the control thermostat, a manual reset high temperature cut-out thermostat just before the cable feeds electricity to the immersion heater element (assuming you go electric).
That should do it! /forums/images/graemlins/cool.gif
Some other tips:
1) Take HW from top of calorifier.
2) Cold feed to bottom.
3) Install a small expansion cylinder into the HW system (just after the water pump) or at another convenient location to allow for HW expansion.
4) Install a pressure relief valve to the calorifier secondary (HW) side, to release water into the bilges. Select discharge position carefully though as it's likely to be a hot discharge!
5) Install, electrically in series with the control thermostat, a manual reset high temperature cut-out thermostat just before the cable feeds electricity to the immersion heater element (assuming you go electric).
That should do it! /forums/images/graemlins/cool.gif
vyv_cox
Well-Known Member
Re mounting as low as possible:-
With a raw-water cooled engine and using an electric circulation pump, it can be quite difficult to fill the system if the calorifier is higher than the engine. You may need to back-fill it from the calorifier if/when you drain it down. Otherwise it will run OK higher than the engine.
With an indirect heating system you might have a problem driving the water around, as the circulation pump on boat engines is designed only to deliver a small head. It was never intended to provide to a relatively large system pressure.
In addition to the points made by John100156, make sure that water to the heating coil goes the opposite way to that of the heated water, i.e. hot goes in at the top and out of the bottom. If not, the reverse thermosyphon can easily be too much for the pump and you will get no flow at all.
With a raw-water cooled engine and using an electric circulation pump, it can be quite difficult to fill the system if the calorifier is higher than the engine. You may need to back-fill it from the calorifier if/when you drain it down. Otherwise it will run OK higher than the engine.
With an indirect heating system you might have a problem driving the water around, as the circulation pump on boat engines is designed only to deliver a small head. It was never intended to provide to a relatively large system pressure.
In addition to the points made by John100156, make sure that water to the heating coil goes the opposite way to that of the heated water, i.e. hot goes in at the top and out of the bottom. If not, the reverse thermosyphon can easily be too much for the pump and you will get no flow at all.
TimfromMersea
Well-Known Member
I have a 281 with factory fitted hot water. The calorifier is a "Quick" Water Heater, a small square one, that fits in the forward inside of the cockpit locker, at the bottom.
PM me with your email adress and I'll email you some pictures if you like.
PM me with your email adress and I'll email you some pictures if you like.
John100156
Well-Known Member
I note what you say and its good to share our thoughts to help others, but:
The boats CW pump should push HW through the cylinder and around the system, it should not air lock. There should be no need to back-pressure.
Most un-pumped secondary domestic cylinders are located at first floor level in houses. The secondary driving pressure often only a few metres (19kPa) compared with a typical boats CW pump pressure (1.4Bar) or 140kPa!
With regard to the primary (engine LTHW) circuit: the primary pump needs to develop sufficient pressure to overcome the resistance of the engine heat exchanger, heating coil inside the calorifier, pipework and control valve - believe me its not that low! Compared to a difference in height of say 2m which will only exert an additional pressure of 19kPa.
But all good opinions which I am sure will benefit the OP. /forums/images/graemlins/cool.gif
The boats CW pump should push HW through the cylinder and around the system, it should not air lock. There should be no need to back-pressure.
Most un-pumped secondary domestic cylinders are located at first floor level in houses. The secondary driving pressure often only a few metres (19kPa) compared with a typical boats CW pump pressure (1.4Bar) or 140kPa!
With regard to the primary (engine LTHW) circuit: the primary pump needs to develop sufficient pressure to overcome the resistance of the engine heat exchanger, heating coil inside the calorifier, pipework and control valve - believe me its not that low! Compared to a difference in height of say 2m which will only exert an additional pressure of 19kPa.
But all good opinions which I am sure will benefit the OP. /forums/images/graemlins/cool.gif
vyv_cox
Well-Known Member
You misunderstand me. I deliberately said that a pump assisted raw water cooled engine can airlock. My boat had a raw-water cooled Bukh with a pump-assisted hot water circulation system. This airlocked badly when first refilled at the beginning of each season, taking much effort working in a confined area to clear.
I was not discussing the presurised water system pump, which I agree will drive water through the calorifier.
On the final point, again, I speak from experience. The heating circuit through the calorifier is plumbed in parallel to the heat exchanger, not in series. If the calorifier is sited too high the water will simply choose not to go through it. I can't quote any figures for the head developed by an automotive circulation pump but it is not high.
I was not discussing the presurised water system pump, which I agree will drive water through the calorifier.
On the final point, again, I speak from experience. The heating circuit through the calorifier is plumbed in parallel to the heat exchanger, not in series. If the calorifier is sited too high the water will simply choose not to go through it. I can't quote any figures for the head developed by an automotive circulation pump but it is not high.
jadwhite
New Member
Thanks for these very helpful responses, I have a much better understanding of the issues involved. One further question though, as the cooling system is indirect does the calorifier need to be mounted below the engine head tank level to prevent air locks forming?
Billjratt
Well-Known Member
I'm currently installing a calorifier. (not in a Benny)
The engine is about 3 metres away from, and a little below, the only place I can put the tank. I'm using 1" (internal) pipe for the coolant, keeping the pipes as straight as possible to avoid "humps" which will trap air. I have a "T" piece on the upper fitting of the heating coil, which will go to a new header tank (from the scrapyard) as it will be the new highest point in the circuit. The original filler cap on the engine header tank will be sealed with something non-setting.
The engine is about 3 metres away from, and a little below, the only place I can put the tank. I'm using 1" (internal) pipe for the coolant, keeping the pipes as straight as possible to avoid "humps" which will trap air. I have a "T" piece on the upper fitting of the heating coil, which will go to a new header tank (from the scrapyard) as it will be the new highest point in the circuit. The original filler cap on the engine header tank will be sealed with something non-setting.
vyv_cox
Well-Known Member
Once the system is full it will remain so. The problem is getting it full in the first place. With water only it's not so difficult but with antifreeze solutions it can get very messy. It's better if you can get the calorifier below the header tank but not essential - it is on my current installation with a horizontal calorifier but wasn't with the original vertical one.
Here's one idea. On VW transporters, from about 1984 onwards, the water cooled diesel version, the top of the radiator in the front of the vehicle is higher than the filler cap at the back. It is very difficult to remove all the air from the top of the radiator. The solution is to braze or solder a dummy filler cap onto the end of a length of pipe about 18 inches long. The whole coolant system is filled through the pipe with the engine running. Once the system is full there is no problem and it can be topped up as normal.
Here's one idea. On VW transporters, from about 1984 onwards, the water cooled diesel version, the top of the radiator in the front of the vehicle is higher than the filler cap at the back. It is very difficult to remove all the air from the top of the radiator. The solution is to braze or solder a dummy filler cap onto the end of a length of pipe about 18 inches long. The whole coolant system is filled through the pipe with the engine running. Once the system is full there is no problem and it can be topped up as normal.
John100156
Well-Known Member
VyV: Yep - understand where your coming from now. Your VW idea with extended fill tube makes sense or a fill point high on the primary if the cyclinder is located high may be useful. IMHO still think placing the cylinder a little higher is not a significant problem.
For OP - The following schematic gives some idea of piping arrangements (location of blending/TMV's to be considered):
/forums/images/graemlins/cool.gif
For OP - The following schematic gives some idea of piping arrangements (location of blending/TMV's to be considered):
/forums/images/graemlins/cool.gif
billcole
Well-Known Member
Yes, ideally the engine header/expansion tank should be the highest point in the engine cooling system, although I remember reading on these forums that people had got away with siting calorifiers with their heating coils slightly higher than the engine header tank. Also bear in mind that each time you draw hot water you need to empty the pipe from calorifier to tap before the hot comes through, and the water left in that pipe when you turn off the tap will then cool down. With just a 10 litre calorifier that could be a few percent of your stored heat lost each time. On my First 305 I've just fitted a calorifier under the basin countertop in the heads, but haven't tried it out yet.