Hot Water

[Gellscom]

Hi

 

We are into the first week of owning our Narrowboat and we have done some reasonably long days heading north to our mooring however we have noticed there is little hot water produced by the engine it is no more than tepid. The webasto heats it up great but not the engine. Coolant levels look good and I wondered if it can get air locked? Had a look round the colorifier and it looks ok there are a couple of valves on the engine circuit but up to now I have held off fiddling.

 

Anyone experienced this and have a fix?

 

thanks in advance

[Bod]

Hi and welcome.

Photos of the valves, showing them in relation to the engine would help greatly, but air-lock does seem likely.

 

Bod.

[Alan de Enfield]

Every NB is a hand-built unique 'one-off' so without either a detailed schematic of your plumbing lay-out, or at least suitable photographs showing the valves and where they go to and come from I don't think anyone is going to be able to offer much assistance.

 

What make is it ?

Who fitted it out ?

What age is it ?

 

If it is a post 1998 boat you should have a full owners manual showing the gas, water, electric and heating circuits. That would be a good place to start.

[MtB]

1 hour ago, Alan de Enfield said:

If it is a post 1998 boat you should have a full owners manual showing the gas, water, electric and heating circuits. That would be a good place to start.

 

Bear in mind the habit (especially in the early days) of boatbuilders, being practical people not noted for their diligent record keeping and office administration procedures, tended to produce that manual for each boat by taking a previous boat manual, copying it and changing the HIN number.  This made the office job easy as no-one checks them or cares what the manual actually says a jot, so long as the administrative box the guvvermint requires to be ticked, gets ticked.

 

So even if the OP acquired a manual with the boat, it might well bear little or no relation to what was actually installed. A better place to start in my opinion, would be to look at the plumbing and follow where all the pipes actually go. And post photos.

 

 

Edited November 6, 2021 by MtB

[ditchcrawler]

Are the pipes from the engine to the calorifier getting too hot to hold?

[Tony Brooks]

and is it uncomfortable to hold the hose running from the top of the engine to the skin tank in your hand when hot?

[Gellscom]

Hi

 

Thanks for all the info the boat is 2008 fitted out by Nantwich Narrowboat Company. No sign of system drawings or Schematics in the manual I’m afraid, I have been sketching them out for the electrics on the way up I will do the same for the plumbing in time. Not had chance to check temps on the pipes and hoses yet the colorifier is a pain to get to, I have to strip the kitchen cupboard out to get to it and the current Mrs M is not amused. It's a bit of a rats nest in there but straight forward enough see images below.

 

After today’s 18 miles the water was tepid again so I reckon it’s likely an airlock or flow issue.

 

it’s not the end of the world for now as we can get hot water other ways.

 

Once again thanks for 5he help and advice.

[ditchcrawler]

Can you reach in and touch any of the uninsulated bits to see if the cylinder is hot.  But as said earlier, check the engine pipes first to make sure the engine is up to temperature.

Forget that, I see you have hot water with the heater so not the mixer valve.

Edited November 6, 2021 by ditchcrawler

[Karen Lea Rainey]

If you can feel  the 2 grey plastic water pipes,

engine in and engine out,

They should both be more or less the same temperature to your hand,

If they are not you obviously  have a blockage / air lock in your engine circuit.

 

Your webasto or ebershauer heater is a totally different water circuit, again these will be an in and out and the same temps to your hand.

There obviously isnt any airlock in that system or you would not get hot water from switching it on.

Start by feeling your skin tank pipes, same temp or not,

air lock there, they will be different temps and so on.

[Karen Lea Rainey]

There looks to be a tap ( on/ off) just above the engine in "text", its almost hidden, 

Is it partially closed screwed down restricting the flow through the calorifier.

Open it fully and check your taps after half an hours engine running.

[David Mack]

Can you follow the pipes from the connections labelled "engine hot" and "engine cold" back to the engine. One of them should run to a connection on the top of the engine. With the engine running and warmed up, that pipe should be hot to the touch. It almost certainly will be close to the engine, but if it cools rapidly even a few inches away then it would appear that water is not circulating through the calorifier as it should. The cause may be an air lock, a closed valve somewhere in the circuit or a blockage in the pipework.

 

Just another thought. Do you have a working thermostat fitted to the engine? If the thermostat element is missing or has failed in the open position, then the engine won't be getting up to temperature, and so the calorifier won't get very hot either. With the engine running and warmed up is the hose from the top of the engine to the top of the skin tank luke warm or almost too hot to hold for any length of time? It should be the latter.

[ditchcrawler]

12 minutes ago, David Mack said:

Can you follow the pipes from the connections labelled "engine hot" and "engine cold" back to the engine. One of them should run to a connection on the top of the engine. With the engine running and warmed up, that pipe should be hot to the touch. It almost certainly will be close to the engine, but if it cools rapidly even a few inches away then it would appear that water is not circulating through the calorifier as it should. The cause may be an air lock, a closed valve somewhere in the circuit or a blockage in the pipework.

 

Just another thought. Do you have a working thermostat fitted to the engine? If the thermostat element is missing or has failed in the open position, then the engine won't be getting up to temperature, and so the calorifier won't get very hot either. With the engine running and warmed up is the hose from the top of the engine to the top of the skin tank luke warm or almost too hot to hold for any length of time? It should be the latter.

This is why both I and Tony asked early on could he hold the pipes on the engine but not had an answer yet.

[Tony Brooks]

Apart from a short while after the first start  of the day the skin tank pipes should NOT be the same temperature. One should be uncomfortably hot for holding and the other cool. I asked about the temperature of the top one after a run to get an idea if the engine thermostat is stuck open/missing.

 

Likewise the engine connection to the calorifier should have a different temperature while the calorifier is warming up. Once up to close to engine temperature both should be the same.

 

I think there is a vertical leg running upwards from the egirine hot is  connection with a tap in it. If so I suspect there is a horizontal section out of view and quiet possibly a downward leg. If so, then that horizontal section is an ideal air lock trap. Maybe fit a bleed point into the top of it. However in many cases I would expect the engine water pump to be powerful enough and shift a high enough volume of water when the thermostat is closed to move the air along the pipe, buy maybe not down a vertical leg.

[Gellscom]

Hi All

 

We came up the Trent from Cromwell today and worked the engine a bit harder, seems that did the trick we have steaming hot water. Either it cleared the airlock or the issue was related to the light duty I was giving the engine?

 

I did check the hoses obviously the were hot and I have drawn a full schematic of the water systems on the boat so all was no in vain.

 

Thanks for all the advice.

[Scholar Gypsy]

2 minutes ago, Gellscom said:

Hi All

 

We came up the Trent from Cromwell today and worked the engine a bit harder, seems that did the trick we have steaming hot water. Either it cleared the airlock or the issue was related to the light duty I was giving the engine?

 

I did check the hoses obviously the were hot and I have drawn a full schematic of the water systems on the boat so all was no in vain.

 

Thanks for all the advice.

Also important to understand how many thermostats you have on your engine (most have 1, but some have 2 and some have none!) and how they control (if at all) the flow to the calorifier circuit. 

For example on mine the coolant just goes around the calorifier circuit until that is heated up, and then (at 82 deg C) the thermostat opens and water also flows through the skin tank. If the engine is not running hard then it takes a bit longer for the hot water tank to heat up, but it still gets to the same temperature, as controlled by the engine thermostat.   As others have said not all boats are the same.

 

[StephenA]

2 minutes ago, Scholar Gypsy said:

Also important to understand how many thermostats you have on your engine (most have 1, but some have 2 and some have none!) and how they control (if at all) the flow to the calorifier circuit. 

For example on mine the coolant just goes around the calorifier circuit until that is heated up, and then (at 82 deg C) the thermostat opens and water also flows through the skin tank. If the engine is not running hard then it takes a bit longer for the hot water tank to heat up, but it still gets to the same temperature, as controlled by the engine thermostat.   As others have said not all boats are the same.

 

 

Whereas on ours the coolant just goes round the engine until the thermostat opens at 82C and then goes via the calorifier to the skin tank.

 

So engine gets up to operating temperature significantly faster than it would if the calorifier was always in the loop, and then we dump all the heat we possibly can into the calorifier....

[Tony Brooks]

11 hours ago, Gellscom said:

Hi All

 

We came up the Trent from Cromwell today and worked the engine a bit harder, seems that did the trick we have steasing hot water. Either it cleared the airlock or the issue was related to the light duty I was giving the engine?

 

I did check the hoses obviously the were hot and I have drawn a full schematic of the water systems on the boat so all was no in vain.

 

11 hours ago, Gellscom said:

Thanks for all the advice.

 

Great news. I trust that if you are ever running to charge the batteries that you do it at the revs that give maximum charging amps and the as the amps drop you slowly decrease the revs but still maintain the highest amps you can. Idle speed is no good for the alternator, engine, or water heating.

 

You do not seem to have done the tests suggested to ensure the engine thermostat is in place and working. An engine will get hot when worked hard with no thermostat but it will take a long time so still worth feeling the skin tank hoses to assess the thermostat.