Calorifier pressure weep

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girlofwight

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Afternoon all

I’m having some issues on accumulator pressure for domestic water generally, and need to get an engineer to look at this when we return our summer cruise.

I’m also having a problem of a drip from the Calorifier pressure release valve which runs to main bilge in hose. It has a constant drip on it. Maybe 1 or 2 drips a minute.

I am wondering whether anyone else is experiencing calorifier problems in this un typically hot uk weather?

I’m trying to ascertain whether this is to do with accumulator pressure and system pressure generally, or whether it’s a separate climate related problem. It is very hot here - Weymouth - at present; I think the engine room may be the coolest spot on board! Conceivably the calorifier could be weeping due to the environment.

The accumulator pressure needs an engineer. The freshwater pump is cycling a little and I can’t seem to get any response in the schrader valve to adjust the accumulator pressure. I’m wondering if either the bladder is perished or the schrader valve is stuck.

Of course, you’ve got to have something to worry about on a hot bank holiday, else it’s not a proper boring experience.
 
Have you tried opening the calorifier pressure relief valve? This could flush out an debris that is preventing it from sealing properly. Usually, rotating the knob clockwise will cause it to open briefly and then close again.

Also, some relief valves operate on either pressure or temperature so, if your system is really hot, this could be causing it to open.
 
Cheers both, yes, my research today led to the override on the PRV and flushing it, which I’ve done. It’s still weeping.

It occurs that as well as being warmer than usual, it’s been on for six days whereas normal pattern of use is just weekends; for all I know it’s wept in extended cruises before. Keeping an eye on it.
 
The ambient temperature won’t make any difference

When on the thermostat regulates it.

They are usually set to 2bar discharge.

Either your water pressure is too high or you need a new relief valve
 
Does your water pump trigger every so often? Ours did which signified a leak.

We had an issue where I <thought> there was a leak from the transom shower hose which I could not trace but water was dripping from it ... Then by luck I noticed a rainbow pattern and a pin hole firing a tiny jet of water from the hot water hose... At the transom shower pipe work. The drip was a lot farther downstream than the problem.

Happened a few times and advice from here was to replace the hose and turn down the thermostat... And thus far its been successful.

Ours is in the Med heat and is on 24/7 when we are on board.
 
in my case the water pump micro switch had failed and the PRV was blowing out water.
A new microswitch costing a pound or two solved the problem.
 
fit a new one get the make off it and search ebay £10 don't go a plumbers merchant they will want to know what boiler its off ,10 min job
 
Oldgit is correct I’d say. Happened on two of our boats. The pressure regulating valve was buggered causing the relief valve to lift.
Ended up just getting a new pump. Almost as cheap.
 
Try turning the pressure relief valve a few times. It may clear any debris in there. If not replace it, they are not expensive.
The leak problem could be exasperated if your accumulator diaphragm has gone as this acts as a buffer. Without it the pump shutting off can cause a surge in pressure (water hammer) which could partially lift PRV
 
When you say accumulator are you referring to the expansion vessel. An accumulator is to act as a a pressurised reservoir to increase water flow, common in situations where flow rate is restricted despite heathy water pressure. If yours is a pressure vessel and the diaphragm is blown this will cause the PRV to drip and also stress the system as pressure increases due to expansion. If possible lift the vessel , if it’s heavy it’s blown. Bouncing the PRV would normally stop the dribbling.
 
girlofwight said:
Afternoon all

I’m having some issues on accumulator pressure for domestic water generally, and need to get an engineer to look at this when we return our summer cruise.

I’m also having a problem of a drip from the Calorifier pressure release valve which runs to main bilge in hose. It has a constant drip on it. Maybe 1 or 2 drips a minute.

I am wondering whether anyone else is experiencing calorifier problems in this un typically hot uk weather?

I’m trying to ascertain whether this is to do with accumulator pressure and system pressure generally, or whether it’s a separate climate related problem. It is very hot here - Weymouth - at present; I think the engine room may be the coolest spot on board! Conceivably the calorifier could be weeping due to the environment.

The accumulator pressure needs an engineer. The freshwater pump is cycling a little and I can’t seem to get any response in the schrader valve to adjust the accumulator pressure. I’m wondering if either the bladder is perished or the schrader valve is stuck.

Of course, you’ve got to have something to worry about on a hot bank holiday, else it’s not a proper boring experience.
Click to expand...


bladder is perished, highly likely, to be the culprit, will cause the cycling and as when the pump switches off at its cut off pressure the pump is still spinning and raises the pressure just a little more.

Also when the PRV is leaking as described, now that it has been lifted, often the dont re seal properly when above a certain age, although some makes have a twisty top, so they can be opened to self rinse.
 
Last edited:
Thanks folks, some things to look at.

It may be when we return to our normal weekend use the calorifier sorts it’s self out, may just be a week or so of continuous running that was the problem. I’ll monitor.

Accumulator wise, I can’t seem to get any response from the Schrader valve in terms of a pressure reading, ability to fill air, ability to release air. On advice of aftersales I’ve got a valve removal tool and a spare valve, so will have a look at the valve and hope it’s that rather than bladder. Easier said than done, Hardy leave a fair bit of space in the engine room but the accumulator is outside the starboard engine and set back - easy enough for agile engineers, but 50s woman with a 5 month old knee replacement, not quite so....
 
I would recommend a car foot pump, add a little air pressure to the accumulator. check your accumulator model, google pressure. problem is heat expansion, accumulator low on pressure, pressure relief valve weeps.
 
Some good advice here but I have to say bitter experience of pressure relief valves has taught me never to expect one to reseal after activating the spring. In fact they are always best to be replaced. The only issue is usually, and I hope someone will tell me differently, where to get a 2.5 bar and 80C PRV from. The one fitted to my boat was a Honeywell and as these things are manufactured for the domestic water market,ie pressurised water cylinders, and most areas of the country now experience water main pressures well above this, they don't do them anymore. They are also called T and P valves because of course that's what they are there for, relief of excess pressure and if the calorifier over heats, the central wax filled capsule will also force the spring to open and allow the water to vent to the bilges if it's got a discharge pipe.
Of course that's where the issue is because our good old bilge pump does it's job and pumps it overboard, often unnoticed.
Let's see what everyone does. Sensible answers please.
 
masterofnone said:
I would recommend a car foot pump, add a little air pressure to the accumulator. check your accumulator model, google pressure. problem is heat expansion, accumulator low on pressure, pressure relief valve weeps.
Click to expand...

That’s what I had tried to do, but schrader valve on accumulator was stuck.

Cue a fun morning of removing it, putting a new one in, over tightening and getting new one stuck, having to remove accumulator for line of sight to extract stuck one, and finally putting another new one in correctly.

Upside, I can now pressurise the accumulator which I couldn’t before. Downside a bilge full of freshwater (why don’t boat builders put a service valve on the pipe from the fresh tank?)
 
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