Hot water not getting very hot?

Skylark

Skylark

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The hot water on my AWB is not getting very hot. This is true using shore power immersion heater and after several hours of motoring. The boat has not been used since the 2019 season. Water tank is now full and flow from taps seems normal and the system is holding pressure.

Any ideas / pointers to check, much appreciated, thanks.
 
Skylark said:
The hot water on my AWB is not getting very hot. This is true using shore power immersion heater and after several hours of motoring. The boat has not been used since the 2019 season. Water tank is now full and flow from taps seems normal and the system is holding pressure.

Any ideas / pointers to check, much appreciated, thanks.
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The temperature reached on shore power will be determined by the immersion heater thermostat maybe that needs adjustment.

The temperature reached by heating from the engine will be limited by the engine temperature. Maybe the engine thermostat is faulty....... Do you have an engine temperature gauge?

It is strange that your water temperature is low whichever heating method you use. Does the calorifier have a thermostatic mixer valve which is set too low?
 
I don't see any connection between engine-supplied hot water and that from an immersion heater, each of which would have its own problems. An immersion heater should have an adjustment. In my case this is a small orange disc that turns. this can be tricky because the numbers are small and it goes the opposite way that I would expect.
 
johnalison said:
I don't see any connection between engine-supplied hot water and that from an immersion heater..........
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Except that, seemingly, both are now generating hot water at a lower temperature than before.

I’ll look for a thermostat adjuster. Engine temperature is normal.
VicS said:
It is strange that your water temperature is low whichever heating method you use. Does the calorifier have a thermostatic mixer valve which is set too low?
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Where is this likely to be located, Vic? How is it likely to be adjustable? Strange that the setting has changed.........
 
Skylark said:
Except that, seemingly, both are now generating hot water at a lower temperature than before.

I’ll look for a thermostat adjuster. Engine temperature is normal.


Where is this likely to be located, Vic? How is it likely to be adjustable? Strange that the setting has changed.........
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If the water is too cold from the immersion and the engine, forget about engine thermostats.

If you have a thermostatic valve it's usually at the tank outlet. As previously mentioned, make/model of calorifier would be useful.
 
PaulRainbow said:
If you have a thermostatic valve it's usually at the tank outlet. As previously mentioned, make/model of calorifier would be useful.
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It’s a Quick Nautic Boiler 40 B3. There is a valve from a port “warm”. This has a rotating knob with + and - direction arrows. It is fully +. It rotates freely. The two pipes and this valve are very hot to the touch but the water is only just above warm, not hot.

I appreciate the help from everyone, thanks.
 
Skylark said:
It’s a Quick Nautic Boiler 40 B3. There is a valve from a port “warm”. This has a rotating knob with + and - direction arrows. It is fully +. It rotates freely. The two pipes and this valve are very hot to the touch but the water is only just above warm, not hot.

I appreciate the help from everyone, thanks.
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Mixer valve then
 
Same issue I had last year. Change out the mixer (these are generic) or even better remove it and your problem will be solved.
 
Skylark said:
It’s a Quick Nautic Boiler 40 B3. There is a valve from a port “warm”. This has a rotating knob with + and - direction arrows. It is fully +. It rotates freely. The two pipes and this valve are very hot to the touch but the water is only just above warm, not hot.

I appreciate the help from everyone, thanks.
Click to expand...

Should look like the valve here: Quick Nautic Mixing Valve Kit | Force 4 Chandlery

Sounds like yours is stuck, try turning it fully cold to fully hot and back a few times. If no good, i think you'll need to change the valve.
 
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Blimey that's even more expensive than I paid for one from Italy before I realised they were all the same generic item!

OP, the valve is there in theory to preserve hot water by mixing some cold and therefore "makes your tank seem bigger". In reality you and your crew will use mixer taps to achieve that same goal because without the mixer the water is actually very hot!
 
lustyd said:
Blimey that's even more expensive than I paid for one from Italy before I realised they were all the same generic item!

OP, the valve is there in theory to preserve hot water by mixing some cold and therefore "makes your tank seem bigger". In reality you and your crew will use mixer taps to achieve that same goal because without the mixer the water is actually very hot!
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That is not why it's there, it is there to stop people being scalded by very hot water, it's been a legal requirement in new house builds for over a decade.
 
Yes, they are pointlessly fitted to new builds too. Several friends had to remove them as their water wasn't very hot. If someone hasn't grown up to understand the hot tap is full of hot water, or to test the water, then they will soon learn, such devices are not needed.

On boats though, it's the small tank thing, and has been for decades.
 
PaulRainbow said:
Sounds like yours is stuck, try turning it fully cold to fully hot and back a few times. If not good, i think you'll need to change the valve.
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Thank you, Paul (and others). I’d post a picture but I don’t know how to post direct from my phone ?

The valve rotates very freely but I don’t know/can’t tell if the valve mechanism is moving. Any tips or should I look for the replacement?
 
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