Calorifiers ... how do they work?

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moonshine33uk

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Would appreciate some advice. I have just bought a boat with a Volvo 2020 and ''hot water provided by both the engine and shore power''

The engine is salt water cooled like my previous 2002 but has a rad cap on a tank which presumably has fresh water in it that then heats water in the hot water tank.

1. How does the water in this enclosed (header?) tank get it's heat?

2. What/where is the calorifier?

3. Presumably the hot water tank gets filled from the boats cold water tank?

4. Big question. If the cold and hot water tanks run dry ... it happens!.. is there a risk of some sort of heating element in the hot water tank overheating a causing a major problem?

5. Does the ''header'' tank need checking like you might a car rad? What would happen if it ran dry? Does it need any additive?

Any thing else that you could tell me would be helpful.

I'm not a total idjit ... just new to the luxury of hot water (on a boat) that hasn't come out of a kettle /forums/images/graemlins/crazy.gif
 
I'd just query the 'salt water cooled'.

All engines draw salt water in for cooling but most pass it through a heat exchanger and use it to cool the liquid in the engine's water jacket in the same way as air cools a car engien's coolant inthe radiator. Your red cap is probably the filler for the engine coolant - a mixture of fresh water & antifreeze. Treat it as you would a car's radiator cap - keep topped up, don't remove while hot and send for an engineer if it keeps going down.

The engine coolant is pumped through a coil inside the calorifier in just the same way as central heating water passes through a coil in your hot water tank.

The calorifier is a cylinder - find it by tracing back the pipe from a hot water tap.

If you run out of water the calorifier will not be damaged.

BUT - the calorifier will also contain an immersion heater connected to shore power. If you have that switched on and the water runs out the element will overheat.
 
Your engine is fresh water cooled. Yes you need to top it up.

The fresh water passes through a heat exchanger and is cooled by sea water.

Like wise, there are pipes from the fresh water in your engine that lead to your califier. Which is just like your cystern at home. The water passes through loads of pipes and transfers the heat to your domestic water.

Duno where your califier is. Look for it!!
 
Sorry if this seems obvious but the Calorifier is a coil inside the hot water tank which is fed by hot water from the engine & heats up the cold water which is fed into the tank from the cold water supply.

Note comments above about letting tank go dry if on shore power.
 
Your Calorifier aka hotwater tank should normally have a standard domestic hot water tank immersion heater running on 240 volts It is protected by a thermocouple as standard for the CE mark but that's only protection.

Cheers
ken
 
I wondered the same thing when I first acquired my boat 2 years ago, as I have a calorifier on my Volvo 2010. It is square and sits in the starboard cockpit locker. Just curious..if the engine coolant is being cooled by the seawater, but has presumably lost some of it's heat in the calorifier before it gets to the engine heat exchanger, does this mean that having a calorifier means your engine runs slightly differently, perhaps cooler? Also should one maintain the calorifier in any way ? I believe mine is a small Rinnai, and the water is wonderfully hot, but there is no instruction manual. Thanks for any info.
 
If the water system has been built correctly, then the inlet (cold) comes into the bottom of the tank and the hot water comes out of the top. This means that if the cold water runs out you cannot get any more hot water out, but the tank can never run dry. Take a look at your domestic hot water system.
 
Leon
The hot water for the calorifier is drawn off before it gets to the heat exchanger so yes your engine will run slightly cooler - that is until the hot water in the calorifier reaches your engine thermostat temp, i.e. if you don't draw off any domestic hot water then it will eventually reach engine temp, after that both engine and hot water supply are running at the same temp.

Peter.
 
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