Jump to content

No hot water!


Nemysys

Featured Posts

Apologies if this is an obvious question or I am talking rubbish.

 

We are currently going through a major rip out and refit of our boat, due to pandemic conditions, everything has been delayed. But we continue now.

The boat hasn’t been run for a while, finally we have got the kitchen back in, using existing pipe work, but not getting hot water. All used to be OK.

 

We have a hot water cylinder, believe it is called a calorifier where the water is heated from the engine. We also have an Alde boiler hardly used. The Alde is currently empty of water as heating pipes have been removed.

 

Ran the engine today after filling up the water tanks, but the water never heated up. This used to work fine, nothing has been changed with the pipe work here.

Next to the cylinder located high up is a difficult to access small tank with a ‘car radiator’ type pressure cap on it, the tank is labelled coolant. Looking at pipe work, this is connected into pipes on the hot water cylinder, but although I cannot see in it, the coolant tank feels empty. Could this be why the water is not heating?

 

What should I put in the ‘coolant tank’? and how much should I put in, for example, keep it half full etc, once the lower pipe work has filled up.

 

Would this be connected with the Alde boat radiator pipe work or would it be a separate circuit?

 

Thanks in advance.

 

Link to comment
Share on other sites

15 minutes ago, Nemysys said:

Apologies if this is an obvious question or I am talking rubbish.

 

We are currently going through a major rip out and refit of our boat, due to pandemic conditions, everything has been delayed. But we continue now.

The boat hasn’t been run for a while, finally we have got the kitchen back in, using existing pipe work, but not getting hot water. All used to be OK.

 

We have a hot water cylinder, believe it is called a calorifier where the water is heated from the engine. We also have an Alde boiler hardly used. The Alde is currently empty of water as heating pipes have been removed.

 

Ran the engine today after filling up the water tanks, but the water never heated up. This used to work fine, nothing has been changed with the pipe work here.

Next to the cylinder located high up is a difficult to access small tank with a ‘car radiator’ type pressure cap on it, the tank is labelled coolant. Looking at pipe work, this is connected into pipes on the hot water cylinder, but although I cannot see in it, the coolant tank feels empty. Could this be why the water is not heating?

 

What should I put in the ‘coolant tank’? and how much should I put in, for example, keep it half full etc, once the lower pipe work has filled up.

 

Would this be connected with the Alde boat radiator pipe work or would it be a separate circuit?

 

Thanks in advance.

 

 

How long did you run the engine for? If less than half an hour at (say) 1200 rpm then try it longer.

 

Please grasp that boats are all one offs and unless you tell us locations and such like we can only guess.

 

Where in the boat is this coolant tank? You don't tell us where the calorifier is located. It would be very rarer to have the engine coolant header tank inside the boat.

 

If its an upright Alde (29xx) then the central heating header tank is in the top of the boiler case.

 

If you have an Alde and engine heated hot water I would expect the calorifier to have two coils it it and draining the Alde system should not prevent engine water heating. But if you have or the boat had a direct raw water cooled engine then the engine may never have heated the hot water.

 

How many pipes are connected or were connected to the calorifier? A photo or two may help identify what you have.

 

Coolant for both the engine and central heating shoudl  be between a 25 and 50%mixture of antifreeze and water.

Edited by Tony Brooks
Link to comment
Share on other sites

30 minutes ago, Nemysys said:

Apologies if this is an obvious question or I am talking rubbish.

 

We are currently going through a major rip out and refit of our boat, due to pandemic conditions, everything has been delayed. But we continue now.

The boat hasn’t been run for a while, finally we have got the kitchen back in, using existing pipe work, but not getting hot water. All used to be OK.

 

We have a hot water cylinder, believe it is called a calorifier where the water is heated from the engine. We also have an Alde boiler hardly used. The Alde is currently empty of water as heating pipes have been removed.

 

Ran the engine today after filling up the water tanks, but the water never heated up. This used to work fine, nothing has been changed with the pipe work here.

Next to the cylinder located high up is a difficult to access small tank with a ‘car radiator’ type pressure cap on it, the tank is labelled coolant. Looking at pipe work, this is connected into pipes on the hot water cylinder, but although I cannot see in it, the coolant tank feels empty. Could this be why the water is not heating?

 

What should I put in the ‘coolant tank’? and how much should I put in, for example, keep it half full etc, once the lower pipe work has filled up.

 

Would this be connected with the Alde boat radiator pipe work or would it be a separate circuit?

 

Thanks in advance.

 

 

 

It sounds a bit odd that you have no way to visually check the fluid level in the tank you talk of, which I presume is the expansion tank. When the engine is run, check that you can feel the pipes warming up that run from the engine to the caloriier coil. There will be an input  and output pipe, back to the engine. If you cannot feel any heat in these pipes, you may be low on coolant and will have to top up the coolant via the expansion tank.  

 

Keep an eye on the engine temperature gauge, to make sure the engine has sufficient coolant in it. 

 

The pipe into the calorifier from the engine should feel fairly hot, if it's circulating coolant from the engine. 

 

 

 

 

 

Edited by Higgs
  • Greenie 1
Link to comment
Share on other sites

Thank you for replies, I ran the engine for 1 to 1 1/2 hours, would’ve expected some hot water by then, based on previous usage. There was a very minor difference in water temperature between hot and cold taps.

 

We don’t use the Alde for hot water, it has always been done by the engine. I know of the Alde tank you mention. 

 

We have a reverse layout, the hot water cylinder and coolant/expansion tank safe right at the back of the cabin, direct line, one meter or so from the top of the engine (most of that 1m is vertical.). BMC 1.8, which also has a skin tank.

 

I cannot visually see the content of the ‘coolant’ tank because it is white, not transparent, but it feels empty when rattled. BTW, the expansion tank looks like it would only hold a pint or so.

 

The pipes you mention were not getting hot, I did check the engine temperature gauge and that was running fine. I think you have confirmed my suspicion that I am low on coolant.

 

So if I fill up with between 25% and 50% antifreeze and water, and fill the expansion tank to half way, I should be good?

 

I’ll get a photo next time I go to the boat, may help clarify things.

 

Edited by Nemysys
Link to comment
Share on other sites

25 minutes ago, Higgs said:

 

I hope it solves the problem, but I think the expansion tank, being opaque, is not making your job very easy. It is important that you don't over fill the expansion tank. 

 

 

As it seems to be inside the boat. A one off overfill is not likely to be a problem except it will make a mess as the system heats up and the liquid expands. Once it has blown the excess liquid off and cooled down again it will be at more or less the correct level. If that tank is the engine header tank and I am far from sure it is.

 

In days gone by a small vehicle coolant expansion tank (think early mini) was used in place of a PRV on the calorifier but from memory they had a 20 psi + pressure cap on them. I would want to know exactly which pipe on the calorifier its connected to before i say more about it.

 

I can't help thinking a BMC 1.8 is likely to just use the header tank that is art of the manifold for filling with coolant rather than mess about with weird pipework to an internal, hard to get a, expansion tank. I suggest the OP checks the level under the pressure cap ON THE ENGINE before putting antifreeze mixture into what may be part of be domestic water system - antifreeze is very poisonous so we need to be sure about what he actually has.

 

 

Edited by Tony Brooks
Link to comment
Share on other sites

A test to see if that small tank is part of the domestic water system.

 

Domestic water pump off and open a tap until the pressure has gone.

 

Close tap and take the cap off that small tank.

 

Get someone to turn the pump on while you keep an eye on that tank. If it fills with water it is part of the domestic water system so do not fill it.

  • Greenie 1
Link to comment
Share on other sites

7 hours ago, Tony Brooks said:

As it seems to be inside the boat. A one off overfill is not likely to be a problem except it will make a mess as the system heats up and the liquid expands. Once it has blown the excess liquid off and cooled down again it will be at more or less the correct level. If that tank is the engine header tank and I am far from sure it is.

 

In days gone by a small vehicle coolant expansion tank (think early mini) was used in place of a PRV on the calorifier but from memory they had a 20 psi + pressure cap on them. I would want to know exactly which pipe on the calorifier its connected to before i say more about it.

 

I can't help thinking a BMC 1.8 is likely to just use the header tank that is art of the manifold for filling with coolant rather than mess about with weird pipework to an internal, hard to get a, expansion tank. I suggest the OP checks the level under the pressure cap ON THE ENGINE before putting antifreeze mixture into what may be part of be domestic water system - antifreeze is very poisonous so we need to be sure about what he actually has.

 

 

 

I also have a BMC and can't use the filling point in the coolant reservoir of the engine; it is too low, lower than the coils in the calorifier. It remains part of the coolant system, but I never take the pressure cap off. My calorifier is an upright type and the header tank that supplies the calorifier coil via the engine is 16" above the engine. The system remains pressurised. 

 

The calorifier has two coils, but I only use one. The spare coil I may connect to a Mikuni that I intend to install, but I haven't yet decided on the system layout for it. 

 

 

 

 

Edited by Higgs
Link to comment
Share on other sites

Thanks all for comments. See attached images.


The small tank labelled ‘coolant’ is the white one at the top left of the photo. The pipes go into the side of the cylinder. One about a 1/3 up, the other about 2/3 up the cylinder. These flexible pipes then head towards the engine bay under the cruiser stern. The gate valve is just between the little tank and the pipe work circuit.

 

There are similar pipes coming out of the cylinder on the opposite side, this is near the Alde, so assume they go there. 

 

I dip tested the small tank, and there was a little bit of fluid  at the bottom, but the level would be below the bottom outlet pipe level.

 

my presumption is that the hoses are also empty as they can be squeezed quite easily.

 

Should I put an antifreeze mix in here, and how far up the tank do I fill it?

 

Thanks

E80559E1-496D-4D83-BABD-BE37BFABBA6C.jpeg

Link to comment
Share on other sites

That is the type of expansion tank that used to be used on old calorifier systems but they have also been used as coolant header tanks. Unfortunate we can't see exactly where it joins the calorifier but as its about 1/4 way down from the top it suggests its probably a heating coil and the blue stains on the connection suggests antifreeze. There is also a PRV fitted so taking those three things together and I think I can be over 50% certain it probably is an engine coolant  header tank but I am not sure what that gate valve is doing or why its been fitted.

 

Take care when refilling it in case its redundant so you are just filling the bilge.

 

Its a small expansion tank for a tank cooled engine, if that is what you have, so only fill until the coolant is just about at the bottom of the tank. Ignore any markings on the tank, they were for car use.

 

If it is lack of coolant that has stopped the water being heated you , may well have to bleed the skin tank if that is the type of cooling system you have and then top up the system again.

 

Edited to add - there is no overflow hose on that tanks and if it is tank cooled it may well spew coolant out as it heats up so I would put a length of hose on the spigot under the cap and lead it into a bucket until you get to know what happens.

 

Edited by Tony Brooks
Link to comment
Share on other sites

Thanks Tony.

 

Not planning on re plumbing this, this is as it was and we were previously getting hot water. Take your point about the ‘spigot’ though


Although you can’t see on the photo, I checked and the pipework definitely connects to the cylinder about 1/3 and 2/3 of the way up.

 

Strangely the gate valve was closed. The gate valve is only between the header tank and the pipe work. Just below the valve the pipe tee’s one way to the engine bay, the other way to the calorifier. The second pipe from the calorifier also goes to the engine bay.

 

The boat has a skin tank, is this likely to be connected in series or parallel to this pipe work? I.e. if I top this up, it will top up the skin tank as well? (If needed)

 

 

 

 

 

                          Little Tank

                                  I

                              Valve

                                  I

Towards engine <——> cylinder 2/3 up

                                                       I

                                                       I

Towards engine <——> cylinder 1/3 up

Link to comment
Share on other sites

56 minutes ago, Nemysys said:

Strangely the gate valve was closed. The gate valve is only between the header tank and the pipe work. Just below the valve the pipe tee’s one way to the engine bay, the other way to the calorifier. The second pipe from the calorifier also goes to the engine bay.

 

The boat has a skin tank, is this likely to be connected in series or parallel to this pipe work? I.e. if I top this up, it will top up the skin tank as well? (If needed)

 

 

I am wondering if this header tank is used to fill the engine and cooling system, including the skin tanks. Once the system is fully bled, then the gate valve is closed allowing the system to pressurise in normal use.

Link to comment
Share on other sites

53 minutes ago, Nemysys said:

Thanks Tony.

 

Not planning on re plumbing this, this is as it was and we were previously getting hot water. Take your point about the ‘spigot’ though


Although you can’t see on the photo, I checked and the pipework definitely connects to the cylinder about 1/3 and 2/3 of the way up.

 

Strangely the gate valve was closed. The gate valve is only between the header tank and the pipe work. Just below the valve the pipe tee’s one way to the engine bay, the other way to the calorifier. The second pipe from the calorifier also goes to the engine bay.

 

The boat has a skin tank, is this likely to be connected in series or parallel to this pipe work? I.e. if I top this up, it will top up the skin tank as well? (If needed)

 

 

 

 

 

                          Little Tank

                                  I

                              Valve

                                  I

Towards engine <——> cylinder 2/3 up

                                                       I

                                                       I

Towards engine <——> cylinder 1/3 up

 

OK so now we can be all but certain this is all related to the cooling system. I now suspect it might be a method of bleeding any air out out the engine coil by opening the gate valve when  the cooling system is up to pressure.

 

The main coolant pipes (engine to tank) will be about 1.5" in diameter, your pipes are about 1/2" ID so in line with what is to be expected for the engine coil circuit. The skin tank and calorifier will be in parallel with each other.

 

What I suggest you do now is to check the coolant level in the engine while cold. Do this via a simmiar cap to the one of the expansion tank but on the top of the exhaust manifold. If the level is more than 1" below the filler neck then top up. Next run the engine until very warm and carefully open that gate valve a little. I suspect you will get air bubbles and then pure coolant. when that happens close the valve and I suspect you will again get engine heated water. When the engine is cold go back to the manifold filler and if necessary top up to about 1" below the filler neck. When the engine is cold after the next run check the level and that will be the normal cold level.

1 minute ago, David Mack said:

 

I am wondering if this header tank is used to fill the engine and cooling system, including the skin tanks. Once the system is fully bled, then the gate valve is closed allowing the system to pressurise in normal use.

As far as I can tell we have no information about access to the normal coolant filler and as the OP say access is difficult with no real signs of spillage I suspect a bleed point is more likely. I read the blue stain as a weeping joint or, more likely the gate valve spindle seal.

Link to comment
Share on other sites

7 hours ago, David Mack said:

If the top of the calorifier coil is higher than the manifold tank cap, then you would need a higher heaader tank for initial filling and bleeding of the calorifier coil.

No  you won't as long as you provide a means of bleeding the air out of the  coil and know how to do it. The engine water pump will push the air out of a bleed in most cases but if not the system pressure when warm in will do it on almost all tank cooled boats running a pressurised cooling system. Once the air is out of the coil it won't "fall out" of the coil when a lower filler cap is taken off because if it did it would create a vacuum.

 

In any case look at the bends in the small bore "filler" pipe if you are correct, they stand an excellent chance of air locking so nothing would flow into the coil. Then there is the need for an explanation for that closed gate valve. A simple pressurised filler would not need one.

Edited by Tony Brooks
Link to comment
Share on other sites

10 hours ago, Nemysys said:

Thank you all.

I won’t be able to get back to the boat until Saturday, will follow advice and keep fingers crossed!

 

When you go about filling the header, shine a light behind it, it will help you to see the level more easily. 

 

 

Edited by Higgs
Link to comment
Share on other sites

Thank you to everyone for their help.


@Tony Brooks - you were correct.

I looked at the coolant level in the engine, added 3 litres to top it up! Ran the engine, bled the air out using the gate valve a few times, and voila, we have hot water. I haven’t had a chance to check since the engine cooled, but suspect it will need a bit more top up. 

 

I have found the bottom pipe connection on the gate valve is leaking, tried tightening but suspect it needs replacing.

  • Greenie 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.