Struggling to heat water

[annad]

Hello all,

 

We are live aboards and after driving for a few hours we have hot water however when moored up and leaving engine in gear and on for a few hours no hot water.... Does any know of anything we might be doing wrong or any alternatives to heating water without hookup.

 

Many thanks for your help and advice!!

[bizzard]

Possibly engine thermostat stuck open or missing.

[annad]

But it has been heating whilst driving...

[Guest]

Hello all,

We are live aboards and after driving for a few hours we have hot water however when moored up and leaving engine in gear and on for a few hours no hot water.... Does any know of anything we might be doing wrong or any alternatives to heating water without hookup.

Many thanks for your help and advice!!

Can't answer your question but be aware that running your engine in gear whilst moored is not allowed on CRT waters. I don't know about other navigations.

[Grace and Favour]

Hi annad,

 

Apart from anything else, please don't run your boat in gear whilst moored, it certainly won't heat the water any quicker, it damages the canal bank, and is against CRT regs.

 

But I agree with Bizzard, it is most likely to be a faulty thermostat

[bizzard]

But it has been heating whilst driving...

Yes but you probably had more power on whilst driving along plus big bursts of astern to pull up.

[Neil2]

Has to be the stat - anyone ever had a boat/car with a stuck open stat knows it's amazing how much cooler the water runs, especially when idling, and it won't do the engine much good in the medium/long term either.

[annad]

Thanks. Do you know how to identify an open thermostat?

[craftycarper]

Take the stat out fill a glass jug with boiling water and drop it in it should open in the hot water and close as it cools

[Chalky]

Take the stat out fill a glass jug with boiling water and drop it in it should open in the hot water and close as it cools

 

Since you've got to partly drain down the system to check the thermostat it's often easier just to replace the thermostat. It's the same amount of work.

[craftycarper]

Should of said check the tension of the fan belt first because if it's slack will give the same problem also agree with chalky but it's still good to check the old one so you can eliminate it as your problem or not

[bizzard]

Start the engine up from cold and keep feeling the engines cooling outlet hose, this should remain coolish until the engine reaches its normal running temperature, at this point the thermostat should open and the hose will quite suddenly get hot. If you have an engine temp gauge study that also.

[annad]

Thanks for your advice. I will look into inspecting/replacing the stat.

Does anybody know of something else I can install to heat the water? Or is running the engine the only option?

[Alan Saunders]

Whilst it is often suggested that running the engine in gear provides a load that may reduce the chance of bore glazing it is not acceptable to CRT as it erodes the bank.

 

The engine coolant is usually circulated through the calorifier via the bypass to the engine thermostat; when the engine is warm most of the flow is through the engine. Possibly, when cruising the engine is running at more then tickover and can force the coolant through the calorifier. Similarly, you need to run your engine at more than tickover to get the best charge into your batteries.

 

The pipe run to the calorifier may be very long or not connected correctly. With a small calorifier within a metre of the engine my Vetus M3.10 (small, high revving, 95C thermostat) produces scalding hot water after 20 minutes at 1200rpm. My old (massive, low revving, 75C thermostat) Gardner takes an hour to warm up before it even begins to warm a larger calorifier three metres away.

 

Good advice above! Bizzard, has the most likely solution. I would do as Chalky suggests, buy and fit a new thermostat and gasket. If the thermostat has been removed it was likely an attempt, maybe temporary, to fix overheating (boiling) of the engine coolant.

 

As a guideline, 40C is a hot shower, >60C is potentially scalding. When my engine is warmed up (10 minutes for the small one) I can only bear to briefly touch the top of it.

 

Good luck and hot showers, Alan

[Grace and Favour]

You could install an instant gas water heater, or, if you have shorepower available, an immersion heater in your calorifier.

[Naughty Cal]

Ours is much the same. If we are just pottering around on the canal and the engine isn't working hard it will take an age to heat the water, it simply won't if you leave the boat tied up with the engine running out of gear.

 

We changed the thermostats (we have two ) thinking this was the problem and it is still exactly the same.

 

Open her up and we have hot water in minutes.

[by'eck]

Hello all,

 

We are live aboards and after driving for a few hours we have hot water however when moored up and leaving engine in gear and on for a few hours no hot water.... Does any know of anything we might be doing wrong or any alternatives to heating water without hookup.

 

Many thanks for your help and advice!!

 

Although a faulty engine thermostat is a possibility, the scenario you describe suggests to me that the engine coolant is simply not hot enough to heat the water with the engine idling. Its possible that the water will remain hot longer by not running the engine after cruising.

[Naughty Cal]

Is the OP's engine raw water cooled?

[Tom Richmond]

It has been suggested to me, when considering the installation of a calorifier, that it be located on the engine side of the stat. Meaning that the coolant heats the calorifier, before the stat opens, and it gets to run to the skin tank.

 

This would seem sensible, offering hot water much quicker. Only dissadvantage being the engine would have to work a bit harder to warm up from cold.

 

I have a lister SW2, it's stat is labelled only 60 deg, and according to the temp gauge it runs at about 50/60 deg. I can lay my hand on top of the rocker covers while it's running (very warm, but not burning!)

[Neil2]

I took the implication that the system had been working fine and that the situation described was a recent fault which leads you to the obvious conclusion that the stat has failed.

 

But re-reading it I wonder if the boat has always performed like this. If so, and it's not a faulty thermostat, it may be the way the calorifier has been plumbed in. Surely most engines will generate enough heat at idle to heat the water in a tank, our last boat certainly did, but if the calorifier feed is on the wrong side of the thermostat, or the return pipe from the calorifier goes into the flow pipe to the skin tank, though I can't think why it would, either case would mean the water would struggle to warm up when the engine was idling.

[Guest]

annad, on 05 Apr 2014 - 8:56 PM, said:

Thanks for your advice. I will look into inspecting/replacing the stat.

Does anybody know of something else I can install to heat the water? Or is running the engine the only option?

 

You could install a diesel heater like a Webasto. Though ours heats the water slower than the engine does.

[peterboat]

My wispergen heats the water during the winter along with the backboiler on the stove (either of the two stoves) during the summer the solar panels have excess power which I use for the immersion heater

 

Peter

[Chalky]

 

As a guideline, 40C is a hot shower, >60C is potentially scalding. When my engine is warmed up (10 minutes for the small one) I can only bear to briefly touch the top of it.

 

 

I've fitted a thermostatic mixing valve (as used in hospitals and care homes) to the output of our calorifier so the temperature never goes above about 50deg C. Under fault conditions the water could potentially reach boiling point so it was designed to cope with that. Probably done too many FMEAs and hazard analysis!

 

You could install a diesel heater like a Webasto. Though ours heats the water slower than the engine does.

 

I looked at that as a possibility. We use about 0.7L per hour to run the engine when cruising. For that I move the boat, generate power (12V & AC), heat the water and heat the boat. A webasto uses 0.5 - 0.7 L per hour and draws power from the batteries which needs to be replaced. I decided to not fit one.

 

Before looking for a plan B to heat the water I'd fix what's already there. Lots of people use the engine to heat water without any problems. It's most likely either a thermostat fault (some boats have 2), a pump fault (pump itself or fan belt), an installation fault (pipes too long so pump can't pump the water round), or an airlock in the system (poor installation not allowing it to be bled properly). Nothing complex and within the scope of most DIYers.

Edited April 6, 2014 by Chalky

[Emerald]

Hi all I spotted this post hoping I might find some help in identifying if I am able to install an immersion heater for the calorifier I have fitted in my boat . If any eagle eyed person could advise from the pictures below I would be grateful