Condensation under bed +1 other

[LoneCruiser]

Good morning and a very happy new year to you all..

 

I have a problem with condensation under my bed where the hot water cylinder is housed.. it is forming on the boat wall where there is no spray foam, is this section not foamed for a reason? And can I use something else maybe insulation tiles, squares to cover the missing section.. ALSO having mentioned hot water cylinder... my PRV is activated every time I move the boat.. thunk it’s on its way out.. are these easy to replace? DIY!!! At present it decants into a plastic bottle... not ideal cos it keeps overflowing and adding to problem..

 

thanking you all in advance 

 

David

[mrsmelly]

Insulation, insulation, insulation, in three words. PRV is a doddle job.

[LoneCruiser]

Bless you.. it’s a bit of a hell hole down there!!! Should of warned you 😱

[nicknorman]

I would expect anything above floor level in the habitable part of the boat to be insulated / sprayfoamed. Looks like a bit of cutting corners went on! Yes I would insulate that area. I guess you could use insulation tiles but I think some Kingspan or equivalent would be better (thicker). I think it will need to be dry before you glue it, which could be difficult to achieve in the present weather conditions.

 

A PRV just screws in so an easy DIY replacement. You might need some PTFE tape if it’s a taper thread. But of course the PRV might be activating because the pressure is too high, not necessarily because it’s faulty.

Oh and make sure any replacement PRV has the same nominal pressure rating. The rating is determined by the strength of the calorifier.

[LoneCruiser]

Yes.. difficult to glue anything whilst it’s cold n damp.. i take it I need to drain water tanks “completely” to remove and replace PRV? I did have someone look at the pressure on my pump but not got back to me as yet!!!

[BEngo]

Does you system have an accumulator?  If so, put a tyre pressure gauge on the accumulator air  charging point with the pump switched  on, taps all closed and pump just stopped.   That will tell you the pump cut out pressure. It wants to be about half a bar, say 7-10  lbs per sq in,  less than the PRV rating.

 

N

[LoneCruiser]

I note you said “above floor level” the area where the foam is missing is below floor/ water line...

Don’t think it has an accumulator?? Was bought as a Sailaway and self fitted by the first owner.. corners do seem to have been cut, and some interesting angles on boat fitting out!!!

[Higgs]

7 minutes ago, LoneCruiser said:

I note you said “above floor level” the area where the foam is missing is below floor/ water line...

 

Yes, but it's above the floor line, and will be open to higher temperatures against the cold surface of the steel. And under the bed does need a suitable amount of ventilation, the body adds to the humidity. Just to be clear, your photo shows missing insulation above the floor level. 

 

 

Edited January 7, 2022 by Higgs

[nicknorman]

32 minutes ago, LoneCruiser said:

I note you said “above floor level” the area where the foam is missing is below floor/ water line...

Don’t think it has an accumulator?? Was bought as a Sailaway and self fitted by the first owner.. corners do seem to have been cut, and some interesting angles on boat fitting out!!!

Below water line isn’t the same as below floor line. Generally the bilges of a narrowboat aren’t sprayfoamed and do suffer from a bit of condensation, but anything in the “habitable zone” ie floor level and above, is normally insulated. Certainly in the case of your picture, most or all of the visible hull is above floor level even if it’s below water level. Anyway the bottom line is to insulate as much of the sides as you can see.

 

Going into a bit of detail, the reason why sides below the floor aren’t sprayfoamed is that typically bilges have steel cross members that support the floor, and these would present a barrier to any water from condensation, plumbing or window leaks from making its way to the back of the boat (lowest point) where it can be removed. Therefore there are gaps/drains in these cross members where they meet the sides, to allow any water to flow. If this area were sprayfoamed it would block these gaps and could lead to an invisible build up of water. In any case these is nothing much gained by sprayfoaming the bottom few inches of the sides below the floor, when the entire baseplate is not insulated.

 

An accumulator is used to “store” water under pressure so the pump doesn’t cut in and out too much. If you can turn the cold tap on, have a fair bit of water come out before the pump cuts in, and or when you turn the tap off the pump continues to run for several seconds, you have an accumulator. If the pump starts as soon as you turn the tap on, turns on and off rapidly when the tap is partially open, and turns off as soon as you close the tap, you don’t have an accumulator.

Some modern pumps claim to be good without an accumulator but I think the general view is that an accumulator is nevertheless a good idea.

Edited January 7, 2022 by nicknorman

[LoneCruiser]

Bless you.. what an informative piece of text.. !!!

 

my pump starts as soon as tap is opened, and stops when tap is turned off... 

 

i’ll keep all your useful advice and information firmly in mind!!

 

ps.. running a dehumidifier under bed in the meantime to keep moisture at bay !!!!

 

thank you to everyone..

 

you are “amazing” as always 

 

Happy Boating

 

David ⚓️

 

 

Edited January 7, 2022 by LoneCruiser
Added text...

[Slow and Steady]

As the rest of your boat has spray foam insulation and to get spray foam insulation to work/stick you have to make the surface wet that might be the best way? you can buy it in aerosol cans.*

 

*It might be too cold to apply at the moment and if it gets out of control it makes a hell of a sticky mess.

 

Has it been removed simply because there was not enough space for the calorifier and plumbing?

 

[blackrose]

2 hours ago, nicknorman said:

I would expect anything above floor level in the habitable part of the boat to be insulated / sprayfoamed. Looks like a bit of cutting corners went on! Yes I would insulate that area. I guess you could use insulation tiles but I think some Kingspan or equivalent would be better (thicker). I think it will need to be dry before you glue it, which could be difficult to achieve in the present weather conditions.

 

 

If you "glue" the kingspan with sprayfoam from a can it will be fine. Sprayfoam likes a bit of moisture on the surface.

[LoneCruiser]

33 minutes ago, Slow and Steady said:

As the rest of your boat has spray foam insulation and to get spray foam insulation to work/stick you have to make the surface wet that might be the best way? you can buy it in aerosol cans.*

 

*It might be too cold to apply at the moment and if it gets out of control it makes a hell of a sticky mess.

 

Has it been removed simply because there was not enough space for the calorifier and plumbing?

 

 

I wondered that.. it’s a neat line where the foam is missing.. but still room to spray.. it’s a mystery, but by the damage caused to the floor covering, it’s been like it for some time...

20 minutes ago, blackrose said:

 

If you "glue" the kingspan with sprayfoam from a can it will be fine. Sprayfoam likes a bit of moisture on the surface.

Great idea!!! 

 

l’ll try that...

 

thank you