Drip Drip Drip

[deckhand]

We have a boat that we have been on since October, new boat.

We kept finding that the bilge, on one side had a good deal of water in it. Kept mopping it out and with all of the rain that we have had since October, just kept thinking that the water was running in from the deck so kept cleaning out the drain runners.

Then we had a canopy fitted which meant that the deck was considerably drier however, the one side of the bilge kept filling up again.

Further investigation showed that the overflow pipe from the hot water tank was dripping. We got the boat builder here to take a look and he cut the pipe and has run this to outside the boat through a small hole drilled in the side.

Over three weeks, we mopped out 3 mop bucket loads of water. The water dripping out of this hole is visible all the time, whether the hot water is on or not, whether the tank water is hot or not.

Would you expect this amount? The builder says that it is normal to have this overflow from the water tank due to pressure. The pump is not kicking in at all. It is just continually dripping.

[koukouvagia]

It's worth checking the pressure relieve valve which may have scale build up which is preventing it from closing properly. Sometime tapping it and turning it on and off will cure it.

 

Ah, just noticed that the boat is new. Therefore scale build up unlikely.

Edited February 2, 2014 by koukouvagia

[Nickhlx]

The fact that the builder says it is normal seems to confirm to me that his advice / knowledge on the matter is painfully lacking. Why would anyone have an "overflow" of whatever sort dripping into the bilge ? ( to cut corners, pricewise ).

 

Of course it should not be dripping, and the fact that it is, means something is not right.

 

Without knowing the system, I would say its likely to be a pressure relief valve not seating properly - Being new it is unlikely to be scale, usually found on older systems, and especially as new, likely a bit of swarf / grit under the sealing seat within the valve. This may be sorted by a quick manual release of pressure with the water blowing the seal clean. However, it could be that the pressure is too high for the valve, or an incorrect pressure rating valve has been installed.

 

Does the valve look something like one of these ? https://www.google.co.uk/shopping/product/14613164496275222668?q=dhw+pressure+relief+valve&rlz=1C1ASUC_enGB567GB567&espv=210&es_sm=122&bav=on.2,or.r_qf.&bvm=bv.60444564,d.ZGU,pv.xjs.s.en_US.TCt7lX562oI.O&biw=1280&bih=895&tch=1&ech=1ψ=8tfuUtPJD6-p7AbDzICoBA.1391384564043.3&ei=kNnuUtibCaSP7AbQxYGAAQ&ved=0CL0BEKkrMAY

 

If so the red conical cap will rotate a little under spring pressure, opening the valve and blowing the muck out ( hopefully).

 

It may be that the valve is not immediately obvious or even "hidden" in the heating device. Trace the pipe back from the dripping end until you find it.

 

Hope that helps

 

Nick

Edited February 2, 2014 by Nickhlx

[deckhand]

Hi Nick, Yes, there is a red valve top on the tank which we gave a quick turn to, this resulted in pulsating blow. Didn't know how long to keep it open so shut it fairly quickly as didn't want to do any harm. I must admit that our alarm bells are telling us that this shouldn't be dripping like this continually which we voiced to the builder who said that "sometimes they do". We were not too happy about just feeding the pipe outside the boat as this was not actually stopping the dripping, solving the water dripping into the bilge area but not solving the drip itself. asking a neighbour, he seemed to suggest that they do drip a bit sometimes which kind of backed up what the builder is saying but we find it somewhat surprising that it does it all the time.

[Ex- Member]

We have a pressure relief valve from our calorifier, It points out of the engine side vent so if it's ever activated most of the water would be ejected outside the boat. I check this valve regularly and it has never leaked or dripped.

 

It's designed to eject water under pressure and should not drip. Ours is connected to the top of the tank which is vertical.

[Quinafloat]

A pressure release valve may well drip while the tank heats as the water increases in volume. It should not drip at all when the tank is cold or cooling as it will then be at "pump" pressure and no more.

[PaulJ]

Just to rule out the obvious as this seems to have been leaking since new-

What is the pressure rating on the pressure relief valve ?-( it will be marked on the red cap)

What pressure is your domestic pump?

I ask because calorifiers from Stone (used to be anyhow) are supplied with 2 bar PRVs and I know Limekilns come with a 2.5 bar PRV. Most common domestic water pumps seem to be 30 psi (tad over 2 bar)

[alan_fincher]

If you are saying what I think you are saying in your very first post, then it absolutely, definitely should not drip at all at such time as the water in the calorifier is not being heated.

 

The pressure relief valve should be chosen and designed to only open at all at pressures greater than your fresh water pump will deliver before it cuts out at its upper pressure limit, so there should never be enough pressure in the cold system to force water past that pressure relief valve.

 

Typically water pumps deliver up to 30 psi, (but some are higher), whereas the valve is designed to open at not less than 3 Bar (which is about 43.5 psi). A 30psi pu,p would not be able to push water through a properly functioning 43.5 psi PRV.

 

One possibility is that they have used a pump with a higher cut out pressure. If for example they have used a pump that can deliver up to 45 psi with a PRV that will pass water at 43.5 psi then it would probably leak, (although for both parts consider any quoted numbers to be approximate - they are not that accurately calibrated usually).

 

There can additionally be reasons why it passes water when the system is heated, but not before, but if yours is passing water even if stone cold, you need to sort that first, because the initial problem is caused by something other than the water expanding on heating.

 

Try to get the builder to tell you....

 

1) The type of fresh water pump used, and its stated cut out pressure

2) The designed opening pressure of the pressure relief valve (PRV).

 

If they are being less than helpful, the pump will usually have at least a model number, and maybe a data plate on it, whereas the PRV may well have its opening pressure stamped or engraved into it - probably just a single digit like "3" or "4". Depending on location you may need torches and/or mirrors to find them!

[Phil Ambrose]

Just to rule out the obvious as this seems to have been leaking since new-

What is the pressure rating on the pressure relief valve ?-( it will be marked on the red cap)

What pressure is your domestic pump?

I ask because calorifiers from Stone (used to be anyhow) are supplied with 2 bar PRVs and I know Limekilns come with a 2.5 bar PRV. Most common domestic water pumps seem to be 30 psi (tad over 2 bar)

I could be wrong (often am) but majority of PRVs are 3 bar including domestic and given that most pumps run at around 2 bar all should be well but if a pump is running at close to 3 bar then dribbling will occur if this is the case, turn down the pressure on the pump. By the same token if the PRV is indeed only 2 bar I would change it for 3 bar. PRVs often dribble with age (I know about this) because the spring in them becomes lazy/weak (I know about this too)

Phil

[n.b.Goldie]

The op says the pump is not kicking in but the overflow is continually dripping. How can thus be? I wonder if they are using an immersion heater off a land line.

 

Regards

Ditchdabbler

[alan_fincher]

The op says the pump is not kicking in but the overflow is continually dripping. How can thus be?

 

If there is an accumulator on the cold water system, the dribbling could to a degree be being supplied by that without the pump needing to cut in.

 

If the OP is drawing off water for regular use, the accumulator will probably be getting fully recharged with water each time they do.

 

Provided not enough has been lost by "dribbling" to drop the pressure to a point where the pump cuts in again before they next open a tap for "real" reasons, they may never get the pump cycling when water is not actively being drawn off.

 

Deckhand talks of "one mop bucket a week", so possibly we are only talking a few pints each day.

[Suzie_q]

We had exactly the same problem. Hardly surprising as Suzie_Q was fitted out by the same builder. We got the overflow connected to the outside, but then for other reasons the hot water was all disconnected to sort out an issue with the immersion and we didn't see the problem again.

 

Now we only get a problem after a long run. When we stop the overflow is pumping out boiling hot water, and the water pump wont stop. I end up turning the water pump off on the fuse board to calm everything down.

 

Are you still getting water in the bilge Deckhand, as I'm having real problems getting the rear deck to drain. Came to the boat yesterday to find 5 inches of water under the engine. No holes leaks or dripping so it must all have been rain water?

[BruceinSanity]

Fitting an expansion tank in the hot water side should stop heating related dribbling, but I agree that the other causes need to be eliminated first.

 

It does annoy me when builders palm their customers off with this "oh it happens" guff. We had this exact problem with Sanity Again almost from new and Peter Mason changed the PRV, then uprated the PRV and finally replaced the expansion tank, which wasn't functioning properly because of a duff bladder. It's now fine.

 

Moral of the story: dribbling can be caused by a bladder problem

[PaulJ]

I could be wrong (often am) but majority of PRVs are 3 bar including domestic and given that most pumps run at around 2 bar all should be well but if a pump is running at close to 3 bar then dribbling will occur if this is the case, turn down the pressure on the pump. By the same token if the PRV is indeed only 2 bar I would change it for 3 bar. PRVs often dribble with age (I know about this) because the spring in them becomes lazy/weak (I know about this too)

Phil

I agree but of the last three domestic systems I have worked on, two had 2 bar PRVs and the other a 2.5 PRV.

In cases where have come across similar problems to what OP has this has been caused by either faulty prv and faulty pressure switches on pumps. Given the builders apparent lack of plumbing skills (perhaps his plumber was on hols ) and it is a new system -my moneys on it being badly matched.But thats only my guessing and assumptions...

I would not change the PRV for a higher rating without checking with the calorifier maker first.

 

Off topic-hope water level your end is ok-downstream is really flowing fast but amazingly low.

[deckhand]

 

Are you still getting water in the bilge Deckhand, as I'm having real problems getting the rear deck to drain. Came to the boat yesterday to find 5 inches of water under the engine. No holes leaks or dripping so it must all have been rain water?

Maybe your drain holes are blocked?

No water in bilge now because they have rerouted the pipe to drip outside instead of into bilge. (They have got to come and paint the bilge area out again though now)!!

We do have an accumulation of water on the deck however when it rains but this is due to the fact that cut outs were not put in the handrails so ALL the water off the roof drains back toward the deck. Builder has said will put in cut outs (all the boats around us have these ) but we have to take boat up to his yard but that will have to wait, there is no way I am going down the Trent at the moment with flooding.

Got another bigger problem with mould at the moment which is also being sorted out by builder but they are coming here to sort that.

I have the paperwork relating to the pump(which had to be replaced back in Dec) and the calorifier so I will take a look and see if I can marry them up against the info given above.

Thanks to everyone for your advice, will come back and let you know.

The op says the pump is not kicking in but the overflow is continually dripping. How can thus be? I wonder if they are using an immersion heater off a land line.

 

Regards

Ditchdabbler

hi, yes using an immersion for the hot water off a landline whilst in marina. Will this make a difference? Will this contribute toward dripping?

[alan_fincher]

hi, yes using an immersion for the hot water off a landline whilst in marina. Will this make a difference? Will this contribute toward dripping?

 

Yes, it could.

 

But if it still drips if you don't heat the water in any way at all, (engine, boiler or immersion), then you have a problem that needs fixing before you even look at what is happening when it is hot.

 

If you get to the stage it only drips when hot, but never when cold, there are other things we can move on to, like does it have an hot water expansion vessel, and if so is that properly pressurised, and functioning correctly, (the kind of stuff Trackman refers to).

 

But you need to be completely clear - are you still dripping if the whole thing is stone cold? If you are look at my previous post about identifying the pressure of the pump, and that at which the release valve should open. It simply should never happen if the whole system stays cold.

[Suzie_q]

Maybe your drain holes are blocked?

No water in bilge now because they have rerouted the pipe to drip outside instead of into bilge. (They have got to come and paint the bilge area out again though now)!!

We do have an accumulation of water on the deck however when it rains but this is due to the fact that cut outs were not put in the handrails so ALL the water off the roof drains back toward the deck. Builder has said will put in cut outs (all the boats around us have these ) but we have to take boat up to his yard but that will have to wait, there is no way I am going down the Trent at the moment with flooding.

Got another bigger problem with mould at the moment which is also being sorted out by builder but they are coming here to sort that.

I have the paperwork relating to the pump(which had to be replaced back in Dec) and the calorifier so I will take a look and see if I can marry them up against the info given above.

Thanks to everyone for your advice, will come back and let you know.

hi, yes using an immersion for the hot water off a landline whilst in marina. Will this make a difference? Will this contribute toward dripping?

It was in the section directly under the engine, so there are no drain holes back to the bilge pump, so as to stop oil getting out.

 

I have the same problem with no cut outs on the hand rails. As you say it all drains back onto the deck, and the only drain points on the rear deck are the gaps between the deck boards. There is no hole or cut outs at the rear.

[Phil Ambrose]

I agree but of the last three domestic systems I have worked on, two had 2 bar PRVs and the other a 2.5 PRV.

In cases where have come across similar problems to what OP has this has been caused by either faulty prv and faulty pressure switches on pumps. Given the builders apparent lack of plumbing skills (perhaps his plumber was on hols ) and it is a new system -my moneys on it being badly matched.But thats only my guessing and assumptions...

I would not change the PRV for a higher rating without checking with the calorifier maker first.

 

Off topic-hope water level your end is ok-downstream is really flowing fast but amazingly low.

Just fallen in, you and I have differeny ideas about "domestic water systems" by domestic I meant Houses and you mean potable water as opposed to cooling water?

Not sure about this but I recall reading that calorifiers are good for 6 bar.

Phil

Oh as far as levels are concerned, we came up about 2 feet over the weekend but are now on the way down again, guess Denver has opened up a bit more

Edited February 3, 2014 by Phil Ambrose

[deckhand]

 

Yes, it could.

 

But if it still drips if you don't heat the water in any way at all, (engine, boiler or immersion), then you have a problem that needs fixing before you even look at what is happening when it is hot.

 

If you get to the stage it only drips when hot, but never when cold, there are other things we can move on to, like does it have an hot water expansion vessel, and if so is that properly pressurised, and functioning correctly, (the kind of stuff Trackman refers to).

 

But you need to be completely clear - are you still dripping if the whole thing is stone cold? If you are look at my previous post about identifying the pressure of the pump, and that at which the release valve should open. It simply should never happen if the whole system stays cold.

There is no hot water in the system at the moment. We had the immersion on yesterday evening for showers last night. The immersion is not on. The engine is not on and neither is the heating(webasto) . But there is water dribbling out of the hole. Just having a look at the paperwork now and will fire off some questions to the builder.

[alan_fincher]

There is no hot water in the system at the moment. We had the immersion on yesterday evening for showers last night. The immersion is not on. The engine is not on and neither is the heating(webasto) . But there is water dribbling out of the hole. Just having a look at the paperwork now and will fire off some questions to the builder.

 

Yes,

 

Then I suggest you ask them what I said.

 

1) The type of fresh water pump used, and its stated cut out pressure

2) The designed opening pressure of the pressure relief valve (PRV).

 

To save time later it would also be worth asking.....

 

3) Is there a non return valve (NRV) between the cold water supply and the cold inlet to the calorifier.

4) Does the hot water system have an Expansion Vessel (EV) fitted on the hot water output.

5) If so what is its capacity, and what do they believe it is "pre charged" to.

 

The above would normally come into play if it only "dribbles" when hot, and not when cold, but of course you may get to the stage where "cold dribbling" is fixed but "hot dribbling" persists, so all that would be useful information to have in the bank. Just trying to plan ahead!

 

 

[smileypete]

Should not get any dribbling at all with a decent system that includes an expansion vessel.

 

Something that can help diagnose these sort of problems is a PRV with built in gauge.

 

http://www.ebay.co.uk/itm/Boiler-Safety-Pressure-Relief-Valve-1-2-BSP-3-BAR-/261169027077

 

Tho I agree with the others, the builder should not try to palm you off! Appointing a good surveyor to oversee the build would hopefully avoid these sort of problems.

 

cheers, Pete.

~smpt~

[deckhand]

Hi, thought I might update on the issues we had. The overflow pipe was rerouted to a hole in side of boat so that now pumps out of the boat, when it needs to. This is how it should have been in the first place but wasn't.

The issue of the water pumping out of the PRV had been caused by the pressures in the pump and the accumulator being too high and close to being the same pressures. The pressure of the pump has now been reset (this had been whacked up (by the fitter) because the water coming out of the galley tap was pulsating out instead of flowing. However, by turning up the pressure, there was little differential between the pump and the accumulator so they were in effect battling against each other. The PRV was in fact doing its job correctly.

 

Thanks to the marine engineer from JRG at Sawley who seems to have solved the issue. (No connection, just a satisfied customer)

 

Thankyou for all your responses on this, these helped me a lot to ask the right questions at the right time.

 

Learning a lot )

 

regards

 

Kim

[BruceinSanity]

Thanks for this, it's always good to hear the end of the story and that things turned out OK.

 

have a good summer!

[deckhand]

Thanks for this, it's always good to hear the end of the story and that things turned out OK.

 

have a good summer!

Thanks, you too (when it gets here - a good spring would be nice to start with)

[MtB]

Thanks for reporting back the result! So often we never get to hear the final resolution of a thread asking the board for help.

 

Keep an eye on it though because as Smiley Pete points out, this pipe should never discharge anything.

 

A PRV only discharges under fault conditions. One or two posters in this thread seem to think occasional discharge is normal and acceptable. It most certainly isn't.

 

MtB

 

 

 

(Spilling and punctuation ediT,)

Edited March 3, 2014 by Mike the Boilerman