Hot Water

[stewart&jenny]

I am running a Beta 38 cooled by a skin tank and supplying heat to a calorifier. See pictures:

 

http://www.cig.canon-europe.com/p?p=GRzDMizRD2T

 

The amount of heat is insufficient to fill a bath. On our last boat, with similar engine but larger cylinder, there was sufficient hot water capacity. So I am thinking of installing a 2nd 43 litre calorifier. I havent yet worked out the installation but I am competent to do it. What concerns me is just how much heat can I take out of the engine? Is there any guidance? The point is, can I actually do harm by removing too much heat?

 

Thanks,

 

Stewart

[Biggles]

Insulated pipe runs would be a start. Is your thermostat opening too soon?

 

Biggles

[stewart&jenny]

Insulated pipe runs would be a start. Is your thermostat opening too soon?

 

Biggles

 

The photographs just show the original siting. The pipework is insulated and thermostat heats up the calorifier just fine.

 

I have since plumbed in a corner bath and now there is insuficient hot water.

[RobinJ]

What concerns me is just how much heat can I take out of the engine? Is there any guidance? The point is, can I actually do harm by removing too much heat?

The heat you are using would go to the skin tank or somewhere else anyway, so there is no limit, except the amount of time the engine has to run to heat the water!

How often are you having a bath?

[Biggles]

I can't see how you would remove too much heat from the engine to do any harm. It has to lose heat somewhere so once the calorifiers are satisfied the rest would be sent to the skin tank.

 

Would a single larger calorifier be a better option? I got one made by Newark Copper cylinders and the price was reasonable. Might work out better and cheaper than a 2nd 43 one and you could get a good price for the used one I suspect. Mine was a standard 120L but they make all sorts of shapes and sizes.

 

Biggles

[stewart&jenny]

The heat you are using would go to the skin tank or somewhere else anyway, so there is no limit, except the amount of time the engine has to run to heat the water!

How often are you having a bath?

 

I thought the same thing till a mechanic at the local watering hole suggested I could cool the engine down suffiently to warp a piston! .... I am not used to pistons warping so I thought I'd come on here and ask

 

The bathing frequency would depend on time of year and how close to water point

[AlanH]

The heat you are using would go to the skin tank or somewhere else anyway, so there is no limit, except the amount of time the engine has to run to heat the water!

Not strictly true. Engines are designed to run at a certain temperature. Too much cooling will cause the engine to run at a low temperature To constantly run an engine too cool will cause excessive wear.

[stewart&jenny]

I can't see how you would remove too much heat from the engine to do any harm. It has to lose heat somewhere so once the calorifiers are satisfied the rest would be sent to the skin tank.

 

Would a single larger calorifier be a better option? I got one made by Newark Copper cylinders and the price was reasonable. Might work out better and cheaper than a 2nd 43 one and you could get a good price for the used one I suspect. Mine was a standard 120L but they make all sorts of shapes and sizes.

 

Biggles

 

Sigh .... now why didn't I think of that! I went and bought an additional calorifier 700x300 for £150. I now have to work out the cost of converting 1" tappings to suitable hose unions .... still, I am quite looking forward to the challenge.

[Biggles]

Not strictly true. Engines are designed to run at a certain temperature. Too much cooling will cause the engine to run at a low temperature To constantly run an engine too cool will cause excessive wear.

 

Agreed, but unlikely the engine would be working that hard on a NB in the first place.

 

Biggles

[WotEver]

Not strictly true. Engines are designed to run at a certain temperature. Too much cooling will cause the engine to run at a low temperature To constantly run an engine too cool will cause excessive wear.

Isn't that why they have thermostats?

 

Tony

 

I thought the same thing till a mechanic at the local watering hole suggested I could cool the engine down suffiently to warp a piston! ....

I'd like a pint of whatever he was drinking.

[RobinJ]

Not strictly true. Engines are designed to run at a certain temperature. Too much cooling will cause the engine to run at a low temperature To constantly run an engine too cool will cause excessive wear.

I agree engines are designed to run at a certain temperature.

Yes they do have thermostats.

But surely the heat going round a calorifier is not pumped, it uses convection, so as far as the engine is concerned nothing has changed?

Possibly is takes a little linger to get up to temperature, so that might increase wear or something over a long time?

[stewart&jenny]

Not strictly true. Engines are designed to run at a certain temperature. Too much cooling will cause the engine to run at a low temperature To constantly run an engine too cool will cause excessive wear.

 

Alan, You inspired me to phone up technical support at Beta Marine!

 

They say that the Beta 38 engines are designed for the hot water take off to be before the thermostat, so that it only opens upon design, and the supply is self limiting so that heat transfer cannot damage the engine.

 

I'm glad I phoned and now I shall go and tinker

[Nose Miner]

If you want to take more heat out of the engine without over cooling it, simply limit or adjust the flow rate to the skin tank. I do this with a standard stop cock on the top of the skin tank. In very cold weather I can completely close it and send all of the waste heat to the calorifier and radiators. Ideally I suppose you could find a way to thermostatically control this process, but I like simple technology.

[stewart&jenny]

If you want to take more heat out of the engine without over cooling it, simply limit or adjust the flow rate to the skin tank. I do this with a standard stop cock on the top of the skin tank. In very cold weather I can completely close it and send all of the waste heat to the calorifier and radiators. Ideally I suppose you could find a way to thermostatically control this process, but I like simple technology.

 

The Beta Marine guy said that the supply take off to the calorifier is before the thermostat. Thinking about it, the diameter of the supply pipe limits the amount of heat that can be delivered so the supply pipe acts as a limiting source anyway

 

At the moment, I have no connection to the radiators except via the secondary coil to the calorifier, a sort of reverse feed if the CH pump on and the gas not lit. One of the things that I have puzzled over is how to keep the rads warm when the multifuel stove is lit in Winter. I have a radiator right at the front and sited to be adjacent to the S/S water tank. The idea being to prevent the tank from freezing and also to keep the front cabin warm. But the CH stat is in the lounge, therefore, at normal settings it doesn't come on. Am now wondering that maybe I have the stat in the wrong place! If I extend the stat to the front cabin and have a thermostatic radiator valve on the lounge radiator, the secondary slightly off topic problem is solved ..... ... thanks ALL

[WotEver]

If I extend the stat to the front cabin and have a thermostatic radiator valve on the lounge radiator, the secondary slightly off topic problem is solved ..... ... thanks ALL

Indeed, at home I have always thought that the stat should be situated in the coldest room of the house, with TRVs on all the other radiators.

 

Tony