Back Boiler Hot Water confusion

[Sus Davy]

Hi All,

 

We have a Morso Squirrel stove with a back boiler. We are having a few issues getting hot water out of it. Sometimes the stove will have only been on for an hour, and we get hot water, other times it will be on for hours (and hot) but no hot water.

 

We have tried changing the temperature settings for when the pump will kick in, tried high and lower, but can't seem to figure it out.

 

Does anyone know much about them who could advise us? I'm a bit fed up of having cold showers now.

 

We also have a calorifer but even with the engine running this drains too much power.

 

Thanks

[MtB]

Have you made sure the water level in the header tank is above the pipe connection into the side of it?

 

And could you expand on your last sentence please? it makes no sense to me at all! What sort of power does it drain? And how do you know?

 

In addition, your Squirrel would normally heat the calorifier so in what sense do you mean you 'also' have a calorifier?

 

 

MtB

[Sus Davy]

Sorry Mike I am not very technical!

 

Will check the header tank.

 

We supposedly can turn the water heater on once the engine/ inverter is on. However every time I try to do this, the inverter cuts out because (I assume) the water heater has pulled all the power out of the batteries and even with the engine on, they cannot recharge quick enough.

 

Sorry to not be more specific / use the right terms but that's all I know.

 

Thanks

[Higgs]

Unlike a central heating system, you cannot turn a morso off and on with a thermostatic control. The water in the boiler needs to be kept circulating through the system, avoiding the possibility of the water boiling in the back boiler. Through the action of thermosyphoning, the simple loop circuit requires no pumps. If the system you have requires a pump, It could be that the water only circulates properly when the pump is active. I can't imagine someone designing a system that would require the pump to be on constantly, though. With the use of valves or stopcocks, one part of the system could be isolated or brought into play whilst the pump was on, to heat water in the calorifier.

 

But, are you asking questions about two problems? If it's morso and backboiler, with rads, then, the level of the coolant water in the system needs to be checked at the header. The systems do need bleeding from time to time, rads, etc.

 

The other question might be about the emersion, and that needs alot of electricity from the inverter. From what you are saying, this part isn't handling the demands very well. Is your calorifier connected to your engine? This will, or should heat the water in a reasonable time, depending on the engine speed, via the engine's cooling system circulating through the coils of the calorifier.

Edited March 31, 2014 by Higgs

[bigste]

I would have thought the immersion should only be used on shore power. If not your batteries will not keep up.

[MtB]

Sorry Mike I am not very technical!

 

 

Oh dear!

 

As the owner of a calorifier attached to a Squirrel solid fuel stove, an engine, AND an inverter I think you need to get technical in a hurry. You are going to need to get to understand how all this works in order to make good use of it.

 

Plenty of threads on here covering the subject. Use the search box (top right of every page) do do a bit of preliminary homework.

 

I suggest starting off by finding out and sorting out in your mind what on earth a 'calorifier' is. The inverter cutting out is a completely different problem. Again, you are going to need to get a grip on some technical stuff before the answers will make even a tiny bit of sense...

 

 

MtB

[bottle]

Sus

 

Let's give you a start to understanding what you probably have:

 

A Morso stove with back boiler that heats water to supply the calorifier (hot water tank) and the radiators, now if it is supplying both it is doubtful you will get hot water to shower with, most of the heat is being dissipated via the radiators, there may be control (valve) to divert the water from the back boiler to either radiators, calorifier or both.

 

The "temperature settings for when the pump will kick in," only does exactly that it does not change the temperature of the water, it is there to turn on the pump because if it did not the water in the back boiler would boil.

 

The calorifier is as mentioned before just a hot water storage tank as would be in a house (just built to different specifications) It is usually heated by the back boiler, the engine or an immersion heater.

 

The immersion heater should only be used to heat the water if you have a shoreline or a generator of sufficient size.

 

If you are running your engine, to run the inverter, to run the immersion this is unnecessary as by running the engine you will heat the water (calorifier) anyway, if you run the engine to heat the water you will also be charging the batteries.

 

I have made an assumption that your engine is water cooled and plumbed in to supply hot water to the calorifier, if air cooled then it will not heat the water.

[Sus Davy]

Thanks for all your help everyone.

 

I shall start trying to learn to be more technical, and have a read up, and hopefully shouldn't have to deal with too many chilly showers!

[JDR]

A calorifier as stated above is just another name for a hot water tank, it may be horizontal or vertical, it might be under the bed or in the engine room.Most calorifiers have an immersion heater which is normally 1kw (1000w) or 2kw. An immersion heater in a house is normally 3kw. If you are plugged into a shoreline in a marina then the immersion will be drawing 1000/240=somewhere around 4amps. Try and power a 1000w device using 12 volt batteries and you are potentially asking your batteries to supply 80+ amps. This will kill your batteries very quickly as you have already found out.

 

As a basic rule of thumb if you are not connected to a 240v shoreline don't use your 12v batteries to heat water.If you have a watercooled engine the heat from the cooling system should provide hot water via a copper coil inside the calorifier.

 

Your backboiler on the Morso may be heating a number of radiators, it may or may not also be connected to the calorifier to provide hot water.There is no standard system,you will have to trace the pipework to confirm what system you have. If the Morso is connected to the calorifier you might need to shut down one or more of the radiators to get enough hot water to the shower.

[Clifford]

If you are SURE that your system relies on a pump to circulate water from the back boiler, and you are SURE that the pump is not running even after your Morso has been on more than a feeble glow for a while, then something is odd, somewhere.

 

(1) The water in the pipes is circulating anyway due to natural convection -"thermosyphoning"- (though in this case your radiators or calorifier would be at least warm)

 

(2) The water is not circulating at all - either because it has boiled dry or because of an airlock or other blockage, or because your pump failed. But in this case you would have heard the water boiling in the back boiler before either blowing up your stove or pipes, or blasting out of the pressure relief valve or overflow pipe. Hmmm, maybe your system DID boil dry non-catastrophically while you were off the boat, and your back boiler now contains only air?

 

By the way, if your backboiler does heat both radiators and calorifier, it may be that your radiators are pumped and your calorifier relies on gravity circulation (thermosyphoning). Or the other way round.

 

As others have said, the inverter or combi (combined charger/inverter) would normally only play a part in heating your calorifier in a very unusual boat setup : all-electric boat with vast battery bank and broken-down genny? boat with massive solar panels and a fully charged bank on a still-sunny day? People with more usual boats don't heat water from battery power.