Leaking join into Paloma heater

[Stroudwater1]

This joint appears to be leaking for some while, as just above in the base of the cover was some kitchen paper to mop up leaking from above from the previous owner. We’ve had the boat for 18 months, not livaboards so use isn’t extensive. Water all switched off and I empty the taps now too in the Summer when leaving. 
 

Looking carefully it appears there’s a leak from the join just above the nut. The paper is dry but clearly the bottom of the unit is  is pretty rusty.  
 

My problem is I’m struggling to undo the nut, I think the unit has the bolt soldered in which makes me reluctant to push too hard. 
 

Perhaps it needs some vinegar to get rid of the calcium deposits here and make the nut less stubborn. The tap is strange as it rotates but there doesn’t seem any leakage at the join it’s from water seeping down I think. 

 

I plan to wrap some PTFE tape round the nut and tighten back up. 
 

Not sure about the rust, probably get rid of  what I can, Owatrol and paint over. 
 

Am I on the right track? Can’t think it would be sensible to heat the nut up to loosen it 

 

any mention of faith gets a unimpressed mark 😂

 

Incidentally I assume it’s anti-clockwise to undo here? 


 

[MtB]

All a bit odd. I don't think the joints are leaking, rather that the copper tube itself on that middle pipe has become porous. 

 

Possibly from electrolysis, but I don't know for sure.

 

 

[Stroudwater1]

This is before I cleaned the nut up. The heater works fine I should add and v pleased with the instant hot water it provides. 
 

Apologies as looking at this picture it seems like the hot water feed is leaking too so perhaps that’s the cause of the rusted area. The paper is bone dry though so you could be right MtB

 

Shame I missed out on the Paloma heater someone gave away a few months ago ☹️ 
 

 

 

[Tony Brooks]

Looking at the corrosion on the flat plate behind the upper part of the copper pipe I fear the leak may be higher up. I am not sure where that copper pipe comes from or what it is for. But I wonder about the heat exchanger weeping.

[MtB]

I think the leak is right HERE:

 

 

 

 

A touch of solder over it should cure it. 

 

 

 

[Tony Brooks]

3 minutes ago, MtB said:

I think the leak is right HERE:

 

 

 

 

A touch of solder over it should cure it. 

 

 

 

 

I agree, it certainly looks that way with the new image.

[alan_fincher]

3 minutes ago, MtB said:

I think the leak is right HERE:

 

 

 

 

A touch of solder over it should cure it. 

 

 

 

 

It's not sur;prising it is leaking there with that great big red arrow stuck into it.

[springy]

The obvious leak across the Brass housing is IIRC the vent from the back of the pressure diaphragm which operates the gas valve. It may be the rubber diaphragm has a slight weep. Though I would certainly check MTBs suggestion above.

 

springy

[MtB]

21 minutes ago, springy said:

The obvious leak across the Brass housing is IIRC the vent from the back of the pressure diaphragm which operates the gas valve. It may be the rubber diaphragm has a slight weep. Though I would certainly check MTBs suggestion above.

 

springy

 

 

Good point. That might actually be the ONLY leak as the water from it will run down into the centre of the casing, and corrode from there. Just as in the picture!

 

 

[Stroudwater1]

My apologies for initially misleading (myself too😞)  on this, the heater is in a large cupboard and it’s difficult to get my head in, and worse to get head in and look upwards with a light. 
 

Thank goodness the second photos show the leak. Thanks for suggesting it’s the diaphragm. 
 

However the nut below does seem to be seeping as all is dry above within the boiler but there’s a tiny amount of  water seeping from between the nut and connector below.
 

It’s odd that the kitchen roll Is dry. How does the diaphragm work? Will dripping from the brass area be irregular according to use? There seems to be a spot where there is a hole that’s calcified ? 
 

Looks like the whole unit may need to come off to rectify. Presume the gas needs a gas fitter to reconnect? I see reconditioned units on the bay which maybe the best option I guess, though will need to ensure that the leaking is still happening in the unit 

 

[pig]

In MTB's photo with the red arrow, the blue stuff below the arrow tip looks like some sort of repair paste, which has also got onto the adjacent silver pipe?

Maybe it's a known fault with a bodge applied?

[springy]

IIRC you can remove the diaphragm in situ without disturbing the gas side, drain the paloma and there are 4 screws holding the aluminium casting to the brass part, the two at the back can be a bit awkward to get a good line, try not to damage the screw heads. It is just possible that  the diaphragm could only be weeping when the unit is in use as the diaphragm moves to allow the gas valve to operate, and seals itself when in the "static" position.

 

springy

 

[Paloma Bob]

The 'O' ring seal on the activating rod has failed, allowing water to pass from the water control valve and exiting via the weep hole.

To replace this its best to remove the whole burner assembly and dismantle the diaphragm housing.

Looking at the condition of the weep hole I would be surprised if the return spring has not rusted away too.