No hot water but new immersion heater?

[NealSmith100]

Hi

 

Out of the blue we had no hot water on Sunday morning. We are moored in a marina and on shoreline with an immersion heater. 

 

No biggie, changed the fuse in case it was that but that didn't seem to fix it. We have had had someone out to change the immersion heater (he said a filament had gone?) but now  - still nothing, It has been on for 9 hours at this stage so it should be hot.

 

It gets hot for a few seconds when we first turn the tape on and then luke warm at best thereafter. We have tried running it for a really long time but  - all we get is 15 - 20 seconds and that is it. 

 

Obviously will call them again when we can (Monday morning) but if there is anything anyone thinks we should be looking at in the meantime, I would appreciate it! 

[andyberg]

Theres normally a small thermal cutout button on the top of the immersion heater, normally between the element connections beneath the cover..

Turn off mains before poking round for it!👍

[Drayke]

4 hours ago, NealSmith100 said:

Hi

 

Out of the blue we had no hot water on Sunday morning. We are moored in a marina and on shoreline with an immersion heater. 

 

No biggie, changed the fuse in case it was that but that didn't seem to fix it. We have had had someone out to change the immersion heater (he said a filament had gone?) but now  - still nothing, It has been on for 9 hours at this stage so it should be hot.

 

It gets hot for a few seconds when we first turn the tape on and then luke warm at best thereafter. We have tried running it for a really long time but  - all we get is 15 - 20 seconds and that is it. 

 

Obviously will call them again when we can (Monday morning) but if there is anything anyone thinks we should be looking at in the meantime, I would appreciate it! 

Maybe its the thermostat playing up.

[Onewheeler]

Changing the element will have meant draining the calorifier to some extent. Air in the pipes?

[Sea Dog]

13 hours ago, NealSmith100 said:

We have had had someone out to change the immersion heater (he said a filament had gone?) but now  - still nothing,

Methinks maybe this chap isn't worth his salt...

Checking that power is reaching the immersion before blaming the element and changing it is an absolute prerequisite, so let's hope he did that, but not confirming that his repair has resolved your problem after the job is done is just plain daft.

Cut your losses and get someone else in would be my advice.

[NealSmith100]

Thanks for the advice all - I have had a tinker this morning and will see if it makes any odds! 

 

(if it does it'll be luck not judgment) 

[Tony Brooks]

5 minutes ago, NealSmith100 said:

Thanks for the advice all - I have had a tinker this morning and will see if it makes any odds! 

 

(if it does it'll be luck not judgment) 

 

Do you have a multi-meter? If so set to a high AC voltage range (shown by a wavy line symbol) and taking care to only hold the INSULTED parts of the two probes, touch them onto the two main terminal with it switched on. You should get a reading of over 200V. Just take acre because if you have no RCD or it is faulty, actually touching an uninsulated part of a probe could kill you.

 

Alternatively, set the meter to a high Ohms (possibly low k Ohm) range and with the immersion  switched OFF touch the two terminals. If you find a 1 or I appears on the right of the window, the heater has an open circuit, so try pushing the overheat cut out mentioned above. Unfortunately, I don'tr know what a sensible cold resistance reading should be.

[Sea Dog]

48 minutes ago, NealSmith100 said:

if it does it'll be luck not judgment

Not sure this is a good starting point with mains voltage electricity... 

[Tony Brooks]

2 minutes ago, Sea Dog said:

Not sure this is a good starting point with mains voltage electricity... 

 

That is the point of my post. Keep hand and fingers away from the terminals and insulated. Then, if the OP finds he has electricity to the immersion, he knows it is a fair bet the unit is faulty in some way. That could be a faulty thermostat, but the terminal needed to check that is often harder to access without a thin probe to touch a screw head.

Edited June 22, 2024 by Tony Brooks

[Sea Dog]

2 minutes ago, Tony Brooks said:

 

That is the point of my post.

I appreciate that Tony, and agree with your advice. The point of my post, based on my interpretation of the OP's poor outcome even after calling in paid 'help' so far, was to be just a little more cautious...  

[Tony Brooks]

10 minutes ago, Sea Dog said:

I appreciate that Tony, and agree with your advice. The point of my post, based on my interpretation of the OP's poor outcome even after calling in paid 'help' so far, was to be just a little more cautious...  

 

I can't get over the number of boaters, often new boaters, who think calling in paid help is the only thing they can do. I appreciate some people are a liability practically, so paid for help in that case is probably a good thing, but I don't believe the number is as great as posts here suggest. After all, people who actually cruise take their boats to places where access is difficult, where a minor breakdown becomes a major problem because of that lack of access and availability of paid help.

[Lady M]

I think it is the same with houses, with people buying in more maintenance services.  

[Tony Brooks]

Ju

3 hours ago, Onewheeler said:

Changing the element will have meant draining the calorifier to some extent. Air in the pipes?

 

I doubt that, but if this is a horizontal cylinder that has not been fitted correctly, it could well be air trapped in the "top" of the cylinder. If the element is in this air, not only would it make the thermostat ineffective, but the element could well overheat and possible burn out (no water to conduct heat away from the element and into the element head).

 

Also, the only way water would be heated is by radiation from the element and a bit of conduction in the air to the surface of the water - hence only seconds of barely warm water.

 

So if this is a horizontal cylinder, I think we need a photo of the end with the pipes on it, plus some of the pipes.

 

 

[NealSmith100]

On 22/06/2024 at 11:42, Tony Brooks said:

So, I did not electrocute myself or do any damage. The water is now definitely heating up - the cupboard and pipes are hot to touch (not scalding) but enough to convince me that the water is hot in there, but for some reason it is not coming out the hot tap anywhere (we only have mixer taps only onboard and the hot side gives me luke warm and the cold side gives me cold - the boat is nearly 6 years old and it has never been an issue before so assume it has to be something to do with the mixer valve but as you were all kind of enough to try and help, I wanted to post an update. 

 

[Tony Brooks]

18 minutes ago, NealSmith100 said:

 

Thanks for the update, unless you have a mixer valve that has jammed close to the calorifier I can't see how it can be something affecting all the mixer taps. This is one reason I asked for a photo of the pipe end of the calorifier.  Surecal calorfiers come ready fitted with a mixer valve, and the better quality boat fitters fit them to other calorifiers to prevent water at engine temperature (80C+) scalding people at the taps. Some mixer valves are adjustable, so if you have one the immersion fitter may have inadvertently twiddled the knob.

[NealSmith100]

There's is a chance that I may have used the wrong term but I watched this on YouTube and figured I could try that and it seems to be have worked! (For now!) 

 

It had to be something that stopped all water coming through once it was clear the water was hot..

 

I know for most people on these forums that's like nothing but for.me it's pretty big.....(Mind you I probably didn't need the immersion heater fix) 

 

 

 

[Tony Brooks]

Be a bit wary with house videos because boats also have a pressure relief valve on the hot system that many houses do not, and PRVs can look very similar to that thermostatic mixing valve.

[ditchcrawler]

Mixer valve marked in red, if the bit connected to the tank is hot but the water coming from it cold that's your problem. I have never changed an immersion heater on a boat but done hundreds in houses and often a lot of scale falls off them into the calorifier