Mushroom vents over a Paloma

[richardf]

Many years ago, on former boats, I used to have 'normal' mushroom vents over the Paloma, but having come back to boating just over a year ago, our new (to us) boat has one of those ugly aluminium cowls that stand up from the roof by a foot or more. I assumed that this was not a stipulation of the BSS. I noticed yesterday that my neighbour has a fixed mushroom with 'scalloped' bases - thus ensuring that they cannot be wound down and closed off. These would also have the advantage of not getting so close to bridges! Does anyone know if they are legal?

[mrsmelly]

Many years ago, on former boats, I used to have 'normal' mushroom vents over the Paloma, but having come back to boating just over a year ago, our new (to us) boat has one of those ugly aluminium cowls that stand up from the roof by a foot or more. I assumed that this was not a stipulation of the BSS. I noticed yesterday that my neighbour has a fixed mushroom with 'scalloped' bases - thus ensuring that they cannot be wound down and closed off. These would also have the advantage of not getting so close to bridges! Does anyone know if they are legal?

 

Hi

 

My last boat had a paloma with mushroom vent over and when the mot was due the examiner did a smoke test which it passed and so I got my mot. That was about 5 years ago so it may have changed and it was a 1981 boat which may also make a difference. I think basically if your boat is above a certain age you are allowed to kill yourself but on newer boats you are supposed to live which of course makes a mockery out of the whole boat mot job anyway.

When I lived aboard before the introduction of the boat mot no one had such a thing and I cant remember dozens of people being killed on a weekly basis on their boats........

[DHutch]

We have a large mushroom over our paloma and ive passed our bss with it every four years since 1991.

 

Our mushrooms have an additional nut and a short stack of washers to prevent them being closed down onto themselves.

 

 

 

Daniel

[PhilR]

We have a large mushroom over our paloma and ive passed our bss with it every four years since 1991.

 

Our mushrooms have an additional nut and a short stack of washers to prevent them being closed down onto themselves.

 

 

 

Daniel

 

My Morco flue with mushroom vent always fails the smoke test. But, it is not a mandatory item with older boats. It is just a case of being sensible when taking a shower - i.e. have plenty of windows open.

 

Phil

[paulcatchpole]

The spillage test in the BSS at 8.10.4/A is an advisory, on which failure will earn you a warning notice.

 

Personally, I wouldn't be happy using anything that failed a spillage test - I believe that'd be ID (Immediately Dangerous) in a house installation inspection, and would get disconnected pronto [i believe, IMHO, I'm not a Kennel Club member...].

 

Mr Fincher has a Morco with a mushroom, I think, which I reckon he said recently passes fine...

 

PC

[Mat B]

Many years ago, on former boats, I used to have 'normal' mushroom vents over the Paloma, but having come back to boating just over a year ago, our new (to us) boat has one of those ugly aluminium cowls that stand up from the roof by a foot or more. I assumed that this was not a stipulation of the BSS. I noticed yesterday that my neighbour has a fixed mushroom with 'scalloped' bases - thus ensuring that they cannot be wound down and closed off. These would also have the advantage of not getting so close to bridges! Does anyone know if they are legal?

 

 

I believe the length of flue is important, my last boat had a mushroom, but the Paloma was mounted quite low so there was a 400mm flue inside the boat.

 

Passed the spill test no problem.

 

m@

[Laurence Hogg]

Many years ago, on former boats, I used to have 'normal' mushroom vents over the Paloma, but having come back to boating just over a year ago, our new (to us) boat has one of those ugly aluminium cowls that stand up from the roof by a foot or more. I assumed that this was not a stipulation of the BSS. I noticed yesterday that my neighbour has a fixed mushroom with 'scalloped' bases - thus ensuring that they cannot be wound down and closed off. These would also have the advantage of not getting so close to bridges! Does anyone know if they are legal?

 

Donkeys years ago the Boatmans Cabin Co vent 2004 which was a fixed permantly open vent was tested by Alde for use over their boilers. It was OK and was approved by them. At that time we stamped the Alde logo into the base so it was recognised as being "approved". I am not sure if this is still relevent for this use as time has moved on but we did sell a lot of them over the years.

[rolimo]

Many years ago, on former boats, I used to have 'normal' mushroom vents over the Paloma, but having come back to boating just over a year ago, our new (to us) boat has one of those ugly aluminium cowls that stand up from the roof by a foot or more. I assumed that this was not a stipulation of the BSS. I noticed yesterday that my neighbour has a fixed mushroom with 'scalloped' bases - thus ensuring that they cannot be wound down and closed off. These would also have the advantage of not getting so close to bridges! Does anyone know if they are legal?

 

down-load the boat safety scheme from the internet and read it. loads of good info should help you prepare for the next dreaded visit. i may seem a bit nerdy but i thought it was a good read.

[sueb]

down-load the boat safety scheme from the internet and read it. loads of good info should help you prepare for the next dreaded visit. i may seem a bit nerdy but i thought it was a good read.

The staff are helpful as well so you can always give them a ring and have a chat. Get a carbon monoxide alarm. I believe there has been one death from co in a bathroom.

Sue

[springy]

Donkeys years ago the Boatmans Cabin Co vent 2004 which was a fixed permantly open vent was tested by Alde for use over their boilers. It was OK and was approved by them. At that time we stamped the Alde logo into the base so it was recognised as being "approved". I am not sure if this is still relevent for this use as time has moved on but we did sell a lot of them over the years.

 

I also have an Alde stamped mushroom on my paloma which I fiited because there wasn't

an approved paloma one. It has never been questioned, or even closely examined IIRC,

it has always passed BSS including smoke tests on the last two.

 

springy

[alan_fincher]

Mr Fincher has a Morco with a mushroom, I think, which I reckon he said recently passes fine...

We do......

 

Albeit a fairly big one, which I have added a sleeve to the thread of, so it cannot be closed down.

 

The boat came that way, and although I expected trouble with the BSS, it passed a spill test fine.

 

This was particularly refreshing, as the Morco was set near the ceiling, and the flue length cut short.

 

When I replaced the Morco D51, (which was there for the BSS), with a D61, I remodelled things to drop the heater, and instead use a full Morco flue that had not been shortened at all.

 

If I were to hit problems with the mushroom vent approach, I'd probably switch to a permanently fitted chimney designed for a solid fuel stove, with a Coolie Hat over the top to keep the weather out. Seems to me that is as good as the normal Morco external flue arrangement, but can easily be taken off for very low bridges.

[Keeping Up]

At one time you had to fit sleeves on all your mushroom vents so they couldn't be screwed down, if you wanted to pass the BSS.

[LoneWolf]

mushroom vents are adjustable!?!

[Radiomariner]

My Morco flue with mushroom vent always fails the smoke test. But, it is not a mandatory item with older boats. It is just a case of being sensible when taking a shower - i.e. have plenty of windows open.

 

Phil

 

 

I believe the length of flue is important, my last boat had a mushroom, but the Paloma was mounted quite low so there was a 400mm flue inside the boat.

 

Passed the spill test no problem.

 

m@

 

Just a week or so ago I examined two boats with mushroom vents. One failed the spill test the other passed. The one that failed had a very short length of flue pipe. As Phil R says, this is an "advisory" item of the exam, however its failure is recorded (On the certificate as well as the Appliance Record) and should you kill yourself you may have difficulty claiming on insurance!

With regard to my failure case, as there were other mandatory failures I returned a few days later and decided to try the spill test again as there was less wind. It failed again after the burner being on full for five minutes. However after running for a further ten minutes, as the test allows, it passed. However I did recommend that the owner consider changing his flue arrangements and fit a CO monitor. Don't think he will his boat has been like that for 20 years.

 

It is my suspicion that the dome remains comparatively cool due to its material (brass) and large surface area cooled by wind therefore relatively "cool" air is trapped under the mushroom, restricting the flow of hot gas. Where the flue is longer there is a greater column of hot gas to force out this cool air, once that happens the dome heats up and the flow subsequently improves

Incidentally, taking the mushroom off completely only made things worse as the unrestricted cold outside air dropping in was greater than the hot gas flow.

[RobinJ]

Many years ago, on former boats, I used to have 'normal' mushroom vents over the Paloma, but having come back to boating just over a year ago, our new (to us) boat has one of those ugly aluminium cowls that stand up from the roof by a foot or more. I assumed that this was not a stipulation of the BSS. I noticed yesterday that my neighbour has a fixed mushroom with 'scalloped' bases - thus ensuring that they cannot be wound down and closed off. These would also have the advantage of not getting so close to bridges! Does anyone know if they are legal?

I have a mushroom on mine, I have the receipt to prove is was purchased as OEM equipment and all three BSC examiners that have seem it accepted it, although one did perform a smoke test to make sure!

 

Only difference I can see to the ones purchased more recently is the way the amount of screw is limited! This actually irritates me as I think in winter it would be nice (when its drained) to close the vent and stop it freezing, but you can't.

[RLWP]

mushroom vents are adjustable!?!

 

Yes. You can screw the cap up and down on a thread, and lock it in place with a big nut which is hard to get to with a spanner.

 

Richard

[blackrose]

I'm surprised to hear people say they have mushroom vents over gas water heater flues. If they pass then they pass, but I wouldn't have one over my water heater flue, same as I wouldn't have a mushroom vent over my solid fuel stove flue.

 

There is a proper chimney/cowl designed for the job, so surely that's what should be used? If the problem is hitting it on bridges then just take it off before you move (and make sure it stays switched off while you move) - in the same way as one might remove the stove chimney prior to moving.

Edited April 15, 2010 by blackrose

[DHutch]

As Phil R says, this is an "advisory" item of the exam, however its failure is recorded (On the certificate as well as the Appliance Record) and should you kill yourself you may have difficulty claiming on insurance!

Exactly, same reason i had our BSS examiner go over ventilation calcs again and get them right such that we passed like every other year. Yes but "its only advisory" wasnt washing we me at all.

 

It was a but windy, and we got a bit of smoke match smoke curling around the hood but it actually performed fairly well and even what had been blown out initially did basically all got back up and out.

- Thats with a 6inch mushroom, and about a 6inch long flue (half an inch from the top of the hood to the lining)

 

Given that the paloma gets used about twice a year, and we always leave all the windows open anyway, and always put it out at night, i would do almost anything to get it to pass with a brass mushroom on it rather than a stainless cowling. Even down to swaping it every four years for the test. Im sorry, but it true.

 

For the gas preasure, gas leak, petrol on board, vent this, window the other, and certainly for anything with the steam plant, it had to be right or im not happy with it let alone any test. With boiler test in the past ive asked an inspector to fail something when i was a bit 50/50 on it (it had ready failed for another minor issue so he was coming back anyway) but just sometimes you have to draw a line. And as i say, 90% of the time we're on the boat we're moving, if we're moving we have steam, if we have steam we have hotwater, paloma remains off and isolated.

 

 

Daniel

[alan_fincher]

I'm surprised to hear people say they have mushroom vents over gas water heater flues. If they pass then they pass, but I wouldn't have one over my water heater flue, same as I wouldn't have a mushroom vent over my solid fuel stove flue.

 

Surely the point ? If tested as safe, then why not ?

 

The comparison to a solid fuel flue isn't really valid - even the proper Morco flue is closed at the top, and doesn't offer any more ventilation than a well open (large) mushroom. All it is giving is a bit of extra flue length, that you may, or may not, need.

 

There is a proper chimney/cowl designed for the job, so surely that's what should be used? If the problem is hitting it on bridges then just take it off before you move (and make sure it stays switched off while you move) - in the same way as one might remove the stove chimney prior to moving.

In our case the problem would not really be overall height.

 

The flue is very close to, (and rearward of), the mount point for our centre rope. A tall object at that point would be an extreme inconvenience.

 

There are versions of these things actually branded to match a given water heater type - if it were ever such an issue, why would a manufacturer have done that?

 

The requirement is that the flue passes a spill test - if it can do that consistently, where's the problem ?

[RobinJ]

I'm surprised to hear people say they have mushroom vents over gas water heater flues. If they pass then they pass, but I wouldn't have one over my water heater flue, same as I wouldn't have a mushroom vent over my solid fuel stove flue.

 

There is a proper chimney/cowl designed for the job, so surely that's what should be used? If the problem is hitting it on bridges then just take it off before you move (and make sure it stays switched off while you move) - in the same way as one might remove the stove chimney prior to moving.

These are not room sealed appliances, so what is the problem with a mushroom?

You can obtain a proper chimney/cowl but are you saying they are designed for boats?

 

I do not want a horrible aluminium flue stuck out of the roof of my boat and many others won't either.

Equally I want to go through some of the lowest tunnels (eg Froghall) without having to worry about removing all the sticking up bits.

Beside which it has been smoke tested by a fully qualified examiner and found to be fit for purpose. After all mushrooms are ventilators they are deisgned to let gases in and out!

[blackrose]

Surely the point ? If tested as safe, then why not ?

 

The comparison to a solid fuel flue isn't really valid - even the proper Morco flue is closed at the top, and doesn't offer any more ventilation than a well open (large) mushroom. All it is giving is a bit of extra flue length, that you may, or may not, need.

 

If being the operative word. If this thread is representative then many won't pass or will only just pass.

 

The comparison with a solid fuel flue is perfectly valid - the vedette cowl on top of my stove chimney is closed at the top but open at the sides and most importantly it is designed for the job - just as the morco flue cowl is designed to vent gas water heater fumes. A mushroom vent is not which is why they often fail..

[RobinJ]

The comparison with a solid fuel flue is perfectly valid - the vedette cowl on top of my stove chimney is closed at the top but open at the sides and most importantly it is designed for the job - just as the morco flue cowl is designed to vent gas water heater fumes. A mushroom vent is not which is why they often fail..

I still don't understand the anymosity toward mushrooms?

You can have a stove chimney with a chinese hat, an enclosed cowl and a mushroom, all have a closed top, allow fumes etc. to vent out the side and all about the same diameter?

That explains why, provided they meet the flow requirements necessary they pass!

[alan_fincher]

If being the operative word. If this thread is representative then many won't pass or will only just pass.

 

There's plenty a Morco / Paloma / Rinnai out there that has the "proper" flue, but which has failed a spill test.

 

I'd rather have one tested as safe, than one that had the "correct" bit of equipment, but fared less well when tested.

 

If an examiner issued an "advisory" on any element of a BSS test on our boat, (not just on the water heater), I would then have to have a long hard think about what to do to correct it, as I do consider safety very important.

 

Until that happens, there are other things I can get more worked up about.

[richardf]

Thanks for your comments. The spill test - how does that work - is it something that you can do yourself to check?

[blackrose]

There's plenty a Morco / Paloma / Rinnai out there that has the "proper" flue, but which has failed a spill test.

 

I'd rather have one tested as safe, than one that had the "correct" bit of equipment, but fared less well when tested.

 

If an examiner issued an "advisory" on any element of a BSS test on our boat, (not just on the water heater), I would then have to have a long hard think about what to do to correct it, as I do consider safety very important.

 

Until that happens, there are other things I can get more worked up about.

 

Any gas water heaters with proper flues which failed a spill test wouldn't have failed because they didn't have the correct flue. Therefore there must have been another reason.

 

I'm not suggesting you get worked up about anything Alan, I just happen to have a different opinion from you, that's all.

Edited April 16, 2010 by blackrose