Adding a second calorifier - possibe?

[RichM]

I have a 60 litre calorifier in my one and only small wardrobe. It's OK for one shower and washing up the dishes a couple of times but cannot expect much more than that without running the Eber/engine.

Would it be feasible to add a second horizontal calorifier in the engine bay? There is sufficient space for another 60 litre calorifier. If so, how much would I be looking at for purchase and installation? Are there any other considerations I'd need to make?

Cheers

[Just Heaven]

You must like long showers! Our calorifier is 55l and we can easily get two showers, sometimes four short ones, plus washing up etc.

Is yours heating up fully? With some only the top half heats up.

We have the engine heating the bottom coil, and the Eber heating the top coil. So the engine heats all the water, but the Eber only the top two thirds.

 

Steve

[Chalky]

We have a thermostatic blend valve on the outlet of the calorifier that mixes cold water with the hot to regulate the temp to 55 deg C. Has the effect of significantly increasing the effective calorifier capacity.

[Dave_P]

I also have a 55l and it's plenty. Do check what temperature you're heating to and how much of the tank is being heated. Fitting a second calorifier could be a tricky job, depending on your engine layout.

 

My first calorifier was in my engine bay (cruiser stern) and when it exploded (long story) I couldn't simply replace it as the old cylinder was tucked in behind the engine and the engine would have had to be craned out to get the new one in. Expensive! I had to install the new calorifier in a cupboard inside the cabin.

[Alan de Enfield]

Our "Sea Boat" has a 26 litre calorifier - we easily get 4 'boat showers' (get wet, turn off the water, soap, rinse, turn off the water) with the thermostat set at 80 degrees on the immersion heater, or heated to 90 degrees ish by the engine.

 

Our Motor cruiser has a 60 litre and we never have any problems with 4 showers and washing pots.

 

The thing to remember is that as soon as you take out 'hot' it is replaced by cold water, reducing the temperature, take out more of what is now 'less hot' it is replaced by cold and the tank is now full of 'warm' water.

 

Everyone gets to shower at the same time (almost) and the days pots get washed concurrently, no problems, everyone 'happy'.

 

"Managing" your water is as tricky as 'managing' your electricity.

[MtB]

To answer the question though, there is no technical reason not to fit a second calorifier. The pair of them will take twice as long to heat up through!

 

Probably a good day's work for a competent boatyard technician. 8 hours at whatever they charge plus the cost of the calorifier and £100 for sundry bits and pieces. Look up calorifier costs on eBay.

[Machpoint005]

To answer the question though, there is no technical reason not to fit a second calorifier. The pair of them will take twice as long to heat up through!

 

Probably a good day's work for a competent boatyard technician. 8 hours at whatever they charge plus the cost of the calorifier and £100 for sundry bits and pieces. Look up calorifier costs on eBay.

 

That might be the key word, Mike. I'd anticipate all sorts of interesting gurgles and air locks.

Could I add my voice to the "water management" advice, please? The Memsahib usually takes her shower before we moor up, so the water is still being reheated.

[peterboat]

I have 2 cauliflowers the small one runs into the larger one system works well when cruising more hot water than I know what to do with!!

[ditchcrawler]

To answer the question though, there is no technical reason not to fit a second calorifier. The pair of them will take twice as long to heat up through!

 

Probably a good day's work for a competent boatyard technician. 8 hours at whatever they charge plus the cost of the calorifier and £100 for sundry bits and pieces. Look up calorifier costs on eBay.

The problem then is how do you draw it off, do you feed cold to the bottom of the first, out of the top with hot to the inlet of the second and then out of that to the taps, and what about the coils, series of parallel?

[RLWP]

I wonder if there is a load of air in the top of your calorifier

 

Richard

[David Mack]

The problem then is how do you draw it off, do you feed cold to the bottom of the first, out of the top with hot to the inlet of the second and then out of that to the taps, and what about the coils, series of parallel?

 

I would connect the domestic hot water as you suggest, and put the coils in series, with the hot water from the engine going first to the second calorifier and then to the first. That way the water you use first will always be hottest.

[dor]

A 60l calorifer should be more than adequate.

 

Some things to check:

Is there a lot of air in the calorifer?

Is the main heating coil the lower one?

Does the heating circuit back-thermosyphon when the engine cools down.

Is the plumbing to the heating coil from the engine properly set up (i.e proper flow at full engine temperature)?

Does the engine or boiler temperature get up to full temperature (around 80C)? The hotter the water the more cold is used to get the right temperature - use a thermostatic shower mixer.

Is the calorifier well insulated (always worth adding some extra, especially if the top of the calorifer insulation feels warm)?

Do you take long showers? I.e. it's a water usage thing - have navy showers and time your washing up to suit the hot water availability.

 

All these and more will be a lot easier to address than fitting a second calorifier, which could result in you just having a lot more warm water.

[Sea Dog]

^^^ Wise words.

 

My 55L calorifier wasn't meeting my demands either til I fixed the thermal siphoning back through the cold engine. Since then it's remarkably impressive just how well it lasts. As someone said earlier, the mixing valve is an effective increase in capacity, but hot water management is crucial even then and the measures have all been highlighted in this thread. It can be done, but it shouldn't need to be.

[Top cat]

I too had back syphoning and would run out of hot water quickly. I diagnosed it by measuring the temperature of the calorifier and the feed and return pipes to the the engine. Once I determined that syphoning was occuring and in what direction I reversed the flow from the engine ( so the syphoning was going the opposite way to the water pump) and fitted a flap non return valve in an ascending pipe. That fixed it and my 60l calorfier now stays hot for 2 days. I also added a lot more insulation but that was not the critical item.

 

Top Cat

[widebeamboy]

An interesting subject that have learnt a few things to check, so thanks guys. Currently installing an L shpae bath and so pretty sure the 75l calorifier I have wont be man enough for a good soak (on shoreline) so an option was to intall another in tandem. Holding off going to the trouble and expense as the bath not fully plumbed in yet so a couple of things on here for me to get checked first, before trying it with 75l and then making a decision.

[peterboat]

I arrived at Castleford Wednesday evening friday morning water still hot that is why I have two cauliflowers and a heatstore. Its no good saying what is good for you because it clearly isnt for the OP otherwise he wouldnt be planning on installing another cauliflower would he?