Caloifier

[SandyD]

Hi,

 

Now getting used to our new boat Ziggy. Most things seem to be working but the hot water is not getting hot, after a two and a half  hour run the water is barely lukewarm any ideas what I should be looking for to see why it is not getting hot?

(If we ran the engine on our previous hire boats the water was really hot after 15mins or so!)

 

Cheers

 

Sandy 

[Jen-in-Wellies]

Welcome to the forum. IS this a new new boat, or a new to you boat?

Most likely an air lock in the pipework between engine and calorifier. Sometimes they clear themselves, if you're lucky.Follow the hoses and pipes from engine to cauliflower and back. It will probably go from somewhere near the top of the engine an d return to near the water pump on the front of the engine on most. Find the highest bits. If you are lucky, the builder will have installed a bleed point there. If not, you'll need to open a joint slightly (not with the engine hot as it will be pressurised) and let any air bubbles out. The air in the pipe will have collected at the high point and stayed there, restricting the coolant circulation.

Edited October 15, 2022 by Jen-in-Wellies

[Tony Brooks]

Assuming no odd valves then probably an airlock in the pipework between engine and calorifier coil. What are the relative heights between the engine coolant header tank and the top calorifier engine coil connection? If the calorifier top engine coil connection is lower try loosening the union and moving it a little to see if any air comes out

[mrsmelly]

What engine? Does engine get up to correct operating temperature? Has thermostat been removed for some reason?

Edited October 15, 2022 by mrsmelly

[StephenA]

How big is the calorifier? Are you talking about bringing it up from cold? On our BMC where the calorifier is in the main cooling loop it take quite a while on the first day to get it up to temperature.

[SandyD]

Thanks both, 

 

I found a pressure valve at the top of the calirofier and bled a load of air out of that (getting overflow into the bilge which I have mopped out!) After running the engine for a few minutes all the pipes that should be getting warm seem to be doing so

 

Sandy

 

PS boat is new to me not brand new!

[Tony Brooks]

5 minutes ago, SandyD said:

Thanks both, 

 

I found a pressure valve at the top of the calirofier and bled a load of air out of that (getting overflow into the bilge which I have mopped out!) After running the engine for a few minutes all the pipes that should be getting warm seem to be doing so

 

Sandy

 

PS boat is new to me not brand new!

 

That makes no logical sense unless the calorifier was full of air. If it is a horizontal one then it may well be fitted incorrectly. If it is a vertical one than the air you released should have come out of the hot taps long ago.

 

The pressure valve is there to vent excess pressure in the calorifier as the water in it heats up and expands. Ideally this will go into an expansion vessel but if there is no vessel, or if the vessel depressurizes then the pressure will build up in the calorifier so without that PRV the calorifier is likely to eventually split.

 

All that valve can do is vent air from the calorifier, it can't vent air from the heating coils, they are totally separate.

 

If you do have a horizontal calorifier I would suggests that you trace the pipes and find the hot water out pipe. The calorifier should be orientated so that hot outlet is the highest one. Otherwise, post photos of the ends of the calorifier showing the pipe connections.

[ditchcrawler]

57 minutes ago, mrsmelly said:

What engine? Does engine get up to correct operating temperature? Has thermostat been removed for some reason?

Please answer this one, some engines wont get very hot, Is it after 2.5 cruising or sitting at tickover?

[SandyD]

2 hrs cruising, having de aired the calorific, the water seems a lot warmer!

[ditchcrawler]

1 hour ago, SandyD said:

2 hrs cruising, having de aired the calorific, the water seems a lot warmer!

Is it a vertical of horizontal one?

[Tony Brooks]

1 minute ago, ditchcrawler said:

Is it a vertical of horizontal one?

 

If it is a horizontal one incorrectly orientated, as I suspect, then this is likely to be an ongoing problem as heating forces dissolved air out of the water, so it builds up in the top of the calorifier. If it is a vertical one then her "cure" makes little sense.

[ditchcrawler]

24 minutes ago, Tony Brooks said:

 

If it is a horizontal one incorrectly orientated, as I suspect, then this is likely to be an ongoing problem as heating forces dissolved air out of the water, so it builds up in the top of the calorifier. If it is a vertical one then her "cure" makes little sense.

And exposing the heating coils to air and not water

[SandyD]

Yes it is horizontal, so either air has built up in it, or it was drained down at some point,

 

Sandy

[Tony Brooks]

2 minutes ago, SandyD said:

Yes it is horizontal, so either air has built up in it, or it was drained down at some point,

 

Sandy

 

Thank you, if you are happy for this to happen again and again then fine, but if you would rather try to prevent the problem reoccurring then either trace the hot water out pipe and make sure it is the highest connection on the calorifier or post photos of the ends of it here so we can try to help.

[SandyD]

Thanks Tony,

 

Now I know it is fixableit will go on the snagging list and I will come back to it at some point!

 

Sandy