condensing oil boiler

[noff]

I did put this thread on boat building & maintenance but no replies so fingers crossed on this one!

We are about to buy a 'domestic' oil fired boiler to run the heating/ hot water on our liveaboard/semi refurbished 1926 Dutch Barge after surviving years on kettles then calorifiers , small wood burner now hopefully central heating.

 

I have read lots of threads on boilers/calorifiers/ heating, etc on various sites and are happy to go the domestic boiler way.

 

I have been informed the condensing type boiler is the way to go and many people seem very happy with their Grant Vortex/ Firebird/W.Bosch etc

 

I contacted a few suppliers and they have told me that condensing boilers cannot run on Diesel (32 sec?) as it can cause damage, one even told me to check the legality of doing so. I am confused.

 

I have tried to go the other way and buy a non condensing boiler but cannot find a supplier ( condensing type only seem to be on offer!!) . its a big HELP please.

 

So....Are Condensing type oil burners ok to re-jet/tweak and run on red diesel without damaging them or not.??

 

Any brands especially model/No folk recommend, any comments/advice would be very welcome especially as winter is a rattling my wheelhouse and our bones!!

 

Nick & Sally

[Big COL]

A quick google and it appears that oil condensing boilers only run on 28sec oil (paraffin/kerosene which gives you a choice either fit a second tank for 28sec oil or find the most efficient boiler that will run on 35 sec oil.

These boilers are still made and when choosing compare the efficiency figures.

[Biggles]

I am interested in this too. I thought of a combination boiler as being the ideal solution for my build needs. Just keeps things simple if it could be done. No calorifier, no additional fuel hassles and domestic reliability and price tag.

 

If I could get one to run on red diesel that could be the total heating solution.

 

Biggles

[Nickhlx]

I am interested in this too. I thought of a combination boiler as being the ideal solution for my build needs. Just keeps things simple if it could be done. No calorifier, no additional fuel hassles and domestic reliability and price tag.

 

If I could get one to run on red diesel that could be the total heating solution.

 

Biggles

 

I am sure boilers exist that run on the heavier oil (35 second) - maybe they are the bigger ones though... certainly most are 28 second. I think my parents one which was a wick boiler ran on that but it was about 40 years ago !!

 

Nick

[The Anonymous Bard]

Sorry not be more specific to your original question as I don't really have a clue but this is something that we can't seem to find an answer to ourselves in planning a liveaboard boat.

 

Good luck and hope you find a feasible answer but...

 

As a back up have you considered a good quality "range" type of cooker that should comfortably run your heating requirements?

 

Appreciating the high initial costs you get a more purpose designed, reliable long term heating system designed and capable of coping with heavy Winter use with an output well suited to your larger Dutch Barge as they apparently run better at higher outputs with more/larger radiators?

[Big COL]

There are plenty of pressure jet boilers that run on 35 sec / gas oil, this is what the bog standard domestic boiler used to be and still are. Drip feed were usually 28sec oil /paraffin/kerosene. The difference between the two systems was that 28sec oil would ignite with a hot wire coil and could be gravity fed /drip feed to the boiler.

In the case of 35sec oil this system would not work as the diesel would not ignite easily,it had to be pumped through a minute jet atomising the fuel and then ignited with an electrical spark, hence the name pressure jet.

Now before you all jump on me and say my stove is gas oil gravity fed and that works, this is true, the two systems described previously are for automatic start up, in the case of drip feed diesel stove these have to be started manually.

The principle of the ignition is different, with a drip feed diesel stove the burner chamber has to be pre-heated, usually with a firelighter, this then heats the base of the burner pot so when you turn the knob on the fuel regulator to start the flow and the diesel arrives at the burner pot, as it dribbles in it is vaporised by the heat in the metal on the base of the burner pot.This vapour is ignited by the remnants of the flame from the firelighter. The difference being here you are igniting a fuel vapour as opposed to igniting an atomised fuel.

A correct burn is when the fuel ignites about 12mm above the burner pot base. with what looks like empty space between but is actually rising vaporised fuel.This is why if you overdo the fuel flow and turn it up too much you can actually cool the burner pot with diesel and the burn rather than being vapour will become diesel boiling and sounding something like a hot chip pan, which is exactly how chip pan fires start - the hot oil boils over and ignites, this then fires the vapour and as it's in free air the cycle just continues.

I used to short cut the start up of my stove by heating the burner pot base to red hot with a turbo gas torch. Start up time 2 minutes as opposed to 10. Just keep your face away from the hole when you start up as the fuel will vapourise very quickly and on ignition will blow up through the lighting port.

Edited November 28, 2009 by Big COL

[noff]

It is now law (2007) that any boiler fitted has to be the condensing seedbukA type although this only applies to houses not boats .

This means that the standard and non condensing oil boilers capable of being re - jetted to run on diesel are becoming scarce as the suppliers have no need to sell them.

I am quite happy if someone tells me I am wrong and can point me to a make / model .

Even a few years ago the threads on this subject suggested buying a regular non condensing boiler ,for example someone bought a Potterton and was very happy so I checked the Potterton site and they do not make that model anymore !!

I am waiting for a reply from someone who has installed a Grant Vortex ( model unknown)in his barge recently who is really pleased with it but needs to find the paperwork to identify it.As soon as I know I will pass it on to those interested.

Yes a diesel combi .... .

As I sit here by our trusty and essential multifuel stove there is torrential rain yet again ... will it ever stop,?? then again if it was snow

[Big COL]

Hi Noff

 

Have you looked at Kuranda and kabola web sites? worth a look.

[Nickhlx]

Hi Noff,

 

When I looked into specifying an oil boiler a couple of years back, there were categories of users that were exempt from having to have a condensing boiler, but as it excluded about 98% of users, I imagine the manufacturers gave up producing them and concentrated on supplying for the masses...

Not sure if that snippet is of use or interest ( or neither !! )

 

Nick

[noff]

Nick.. . I think you hit the nail on the head, not a big enough market.. but I will keep searching.

 

Regarding Kabola/Kuranda those boilers are massive money and by all accounts do not justify their huge cost compared with a 'domestic' boiler ( according to others who know more about these things than I ever will)

 

We do have a 12 year old rayburn oil beast on board which may need a new back boiler (£800) besides other things so it seemed to be a cheaper ,more efficient and quicker way to go the domestic boiler route then one day have the Rayburn repaired /sell it?.

 

The other choice we have to make is whether to run on Kerosene or Diesel.

The domestic boilers are ready to go and probably more efficient on the cheaper Kero but not sure about its availability in Uk and abroad. ( the dream).

We also have a Refleks oil burner stove which is our last line of defence when its freezing, its very reliable but can get through the diesel as it is the hot plate/ vaporising type Col mentioned.

Sorry for erratic reply , just thoughts as they pop into my head. Thanks for your comments .. more please

[Big COL]

Hi

How about a Hurricane, 9kw burns gas oil without any problem.

[Nickhlx]

Nick.. . I think you hit the nail on the head, not a big enough market.. but I will keep searching.

 

Regarding Kabola/Kuranda those boilers are massive money and by all accounts do not justify their huge cost compared with a 'domestic' boiler ( according to others who know more about these things than I ever will)

 

We do have a 12 year old rayburn oil beast on board which may need a new back boiler (£800) besides other things so it seemed to be a cheaper ,more efficient and quicker way to go the domestic boiler route then one day have the Rayburn repaired /sell it?.

 

The other choice we have to make is whether to run on Kerosene or Diesel.

The domestic boilers are ready to go and probably more efficient on the cheaper Kero but not sure about its availability in Uk and abroad. ( the dream).

We also have a Refleks oil burner stove which is our last line of defence when its freezing, its very reliable but can get through the diesel as it is the hot plate/ vaporising type Col mentioned.

Sorry for erratic reply , just thoughts as they pop into my head. Thanks for your comments .. more please

 

 

OK - some more thoughts....

 

Well, if there is gas on the boat, how about using it for heating ? Domestic gas boilers are probably the most common source of heating in houses these days and many /most / all can be converted to run on Propane - being made in vast quantities, they are naturally cheap ( from about £300 upwards) and you would only need the very smallest on a boat. However most are modulating boilers, which modulate the flame down according to the flow / need for heat. I am very familiar with gas boilers and the last I installed was converted to run off (a bulk tank of) propane - I had to order ( from B and Q) with the propane conversion done by the manufacturers, but it only took a week to arrive. In the end though, the boat builder really recommended diesel central heating, ( Webasto) and, wanting, to keep on the right side of him ( being the expert) I didn't want to start him working in unfamiliar territory, so have resigned myself to learn all about diesel heaters now :-) - so far so good and no probs... Possible downsides would include storage of gas, although even 13kgs cylinders should last long enough to avoid being changed too often - a definite advantage is the smallest you are likely to find is going to heat up the DHW cylinder ( and boat) in super-quick time, as it will probably be at least twice the output of what you need, so will be working throttled right back when up to temp. and very quickly be able to get the whole boat up to temp. As regards people saying it's "unsafe" - Eh ? It's used in most houses so why should it suddenly become unsafe on a boat (assuming proper installation !!) and bilge ventilation / gas detection devices ? It should be a room-sealed boiler though, so there is no possibility of gas escaping into the boat if the fail-safe devices fail unsafe ! Most are anyway, but you should ensure it is if you go that route.

 

.... and Kerosene ...

 

I use Kerosene at home for heating ( 28 second home heating oil) and it costs around 35p/litre... it is very marginally less calorific than diesel, but significantly less expensive and a much cleaner fuel. I too have a Lockgate Refleks stove in the front of the boat, and I was insistent on installing separate fuel tanks with a pipe going the length of the boat, so either heater could run off either fore or aft tanks.. however I have been running both the heaters off kerosene as both work well running on it, and may ( will ) stay cleaner too, with less soot build-up.

 

The only possible downside to Kerosene I can think of is the transfer to the boat. However, we are not CCing and taking one or two Jerry cans up each time ( or even most times) we go, is no hardship. For transfer I use a Jiggle syphon - it's dead easy and I never spill a drop... However with the anticipated minimal servicing and the approx halving in costs, taking maintenance into account, it fully justifies itself in my opinion. There are no duty issues either, as it's taxed for heating in the first place.

 

I am very happy with the set-up and apart from maybe looking at gas again, would do the same again...

 

Nick

[Biggles]

Anything boat specific is very expensive just because it is a non domestic appliance. Talk of kerro or 28 second oil is pointless IMO as 1. Who wants 2 tanks, 2. Availability and delivery of kerro. 1 fuel keeps it simple. OK there is a price overhead for red, but again IMO its a cost worth bearing for the sake of simplicity and supply.

 

So if combination boilers are the norm now due to legislation in a domestic situation its understandable that the manufacturers have deleted combination boilers from their catalogues.

 

Biggles

[Nickhlx]

Anything boat specific is very expensive just because it is a non domestic appliance. Talk of kerro or 28 second oil is pointless IMO as 1. Who wants 2 tanks, 2. Availability and delivery of kerro. 1 fuel keeps it simple. OK there is a price overhead for red, but again IMO its a cost worth bearing for the sake of simplicity and supply.

 

So if combination boilers are the norm now due to legislation in a domestic situation its understandable that the manufacturers have deleted combination boilers from their catalogues.

 

Biggles

 

 

That's fine by me, but I WANTED two tanks - so to answer one of your questions - me ! . I HAVE Kerosene at home ( answering another) and, with its advantages I wanted to use it. Also, in a couple of years, when the forthcoming changes to our diesel comes through, I wanted two tanks so I could treat one whilst having the other to run off. To me, the extra, added complexity I am able to cope with, appreciate your point, but IMO the small increment in cost for the significant advantages was worth it else I wouldn't have done it. The builder was quite impressed too -

 

Nick

[noff]

I am out all day so will reply later with my thoughts, thanks

[number four]

That's fine by me, but I WANTED two tanks - so to answer one of your questions - me ! . I HAVE Kerosene at home ( answering another) and, with its advantages I wanted to use it. Also, in a couple of years, when the forthcoming changes to our diesel comes through, I wanted two tanks so I could treat one whilst having the other to run off. To me, the extra, added complexity I am able to cope with, appreciate your point, but IMO the small increment in cost for the significant advantages was worth it else I wouldn't have done it. The builder was quite impressed too -

 

Nick

 

we are planing a system with 2 tanks of 500l so to take advantage of the tax hear and in france

the info you gave on heating fuel sounds like a good idear whats the minimum order you can get for domestic delivery. i know the lorries come with long hoses so if i went to a sutable moring cant see why i cant buy 500l at a time bulk buy.

do you think this is viable?

[GUMPY]

we are planing a system with 2 tanks of 500l so to take advantage of the tax hear and in france

the info you gave on heating fuel sounds like a good idear whats the minimum order you can get for domestic delivery. i know the lorries come with long hoses so if i went to a sutable moring cant see why i cant buy 500l at a time bulk buy.

do you think this is viable?

 

 

Each tank will have to be at least 600l to enable you to get a bulk delivery otherwise you will have to store some in cans.

My tanks are 750 and 500 so i can do a 1000l delivery if I need too. Remember that the price drops at 1000l

[number four]

Each tank will have to be at least 600l to enable you to get a bulk delivery otherwise you will have to store some in cans.

My tanks are 750 and 500 so i can do a 1000l delivery if I need too. Remember that the price drops at 1000l

 

sorry did not make it clear

500l for red

500l for 28sec

have had a google and it seems 500l is the minimum for most bulk deliverys

so plan would be to run heating all winter and then order 500l in spring when tank is empty and have 2x25l jerry in case it wont all fit.

[GUMPY]

sorry did not make it clear

500l for red

500l for 28sec

have had a google and it seems 500l is the minimum for most bulk deliverys

so plan would be to run heating all winter and then order 500l in spring when tank is empty and have 2x25l jerry in case it wont all fit.

yes I understood that but I would go for tanks bigger than 500 as they will never be completely empty when you need to fill them.

Also the filling rate from a tanker is higher than from a pump so you would bw advised to go for a big bereather to avoid splash back. I sed to get through about 1100L each winter when i was on diesel.

Edited November 29, 2009 by idleness

[rjasmith]

OK - some more thoughts....

 

... and Kerosene ...

 

I use Kerosene at home for heating ( 28 second home heating oil) and it costs around 35p/litre... it is very marginally less calorific than diesel, but significantly less expensive and a much cleaner fuel.

 

(snipped)

 

Nick,

 

Very interesting to hear your plans for different fuels as I'm thinking of doing the same. Just a very small correction to your words above in kerosene's favour! It is marginally greater in calorific value than gas oil (red diesel), not less! See here (NPL data). This is as well as all the other things you said about cleaner burn etc.

 

I've gone down the additional tank route - in fact we have two tanks either side of the foredeck in addition to the main propulsion tank at the back. We have Wallas cookers (on one front tank) and a Kabola E series boiler (on the other) and although they are presently set up for diesel I might look into getting them re done for kerosene. If one or other proves a bit difficult/costly to reset it can stay on diesel and the fuel put into the relevant tank chosen accordingly.

 

I realise this is only going to be of interest to folks who are in the early phases of designing/building a boat.

 

Like you, we use kerosene at home in our ancient non condensing, non combi Perrymatic boiler so supply to the boat can also be by regular Jerry can.

 

I haven't tried looking on eBay and perhaps it won't be everyones choice to do this but are reasonable condition non condensing second hand oil boilers on there going for a song? This could then be set up for 35 sec and might solve the OP's problem

 

Years ago (well before eBay) I picked up an old Potterton for a few quid that still heats an outbuilding we have here splendidly from the house fuel tanks.

 

Richard

[number four]

yes I understood that but I would go for tanks bigger than 500 as they will never be completely empty when you need to fill them.

Also the filling rate from a tanker is higher than from a pump so you would bw advised to go for a big bereather to avoid splash back. I sed to get through about 1100L each winter when i was on diesel.

 

big breather is a good point

but 500l is the best we can do for tank size but i will ask the builder when we get near that stage but i am restricted as i want prefab plastic tanks.

Edited November 29, 2009 by number four

[GUMPY]

big breather is a good point

but 500l is the best we can do for tank size but i will ask the builder when we get near that stage but i am restricted as i want prefab plastic tanks.

Will plaatic be ok for bss?

My tanks are mild steel which is fine for diesel.

[number four]

Will plaatic be ok for bss?

My tanks are mild steel which is fine for diesel.

as far as i know there is no problem, and they are fitted to every production yacht made nowdays. there are 4 on my boat as seen in the avitar.

[Nickhlx]

I think the calorific value of Red vs. Kerosene is debatable as some sites say one way and some the other....

 

http://www.engineeringtoolbox.com/fuels-higher-calorific-values-d_169.html at the bottom says the heavier the fuel the higher the calorific value, which makes sense as its denser ( more carbon in it ?) which is what I alaways remember from school

 

This also applies to commercial Butane / Propane - Butane is more calorific 118 MJ/CuM compared to Propane at 94 Mj/CuM,

http://www.kayelaby.npl.co.uk/chemistry/3_11/3_11_4.html although there are sites that claim otherwise too Weird !!

 

So I guess it could be either way depending on the recipe at the time of refining... either way there's not likely to be much in it in practice ... the price differentials and practicalities are far more significant. ( i.e. Butane useless, as boils at 32 Deg F ) so very low pressure on cold days....

 

Nick

Edited November 29, 2009 by Nickhlx

[noff]

back again.. good to see thread expanding.

We have also considered the option of two fuels ie Kero/Diesel .

We have a 1000L mild steel tank about to go into the engine room which is for heating only.

I did consider cutting this tank into two 500L tanks but as mentioned you really need 1000L delivery to get the discount, so its one big tank... Kero or diesel ???

I think that I will go Kero for price/efficiency as discussed but will allow myself the 'luxury' of a 500L tank that will be for Red Diesel in the future if I ever need to change fuel i:e just cannot obtain Kero .I will also have to buy new jets or whatever is required to convert to diesel.

I was warned off plastic tanks for fuel due to their ability to melt in a fire and thus feed the flames so to speak. In fact an incident describing this very scenario was described which occured to a Dutch barge.

BUT !! As you say many vessels are fitted with plastic fuel tanks, you only have to look at outboards, so as long as they are accepted by the BSS my 'luxury' tank will probably be plastic but there is that old niggling doubt about their durability re movement/flexing etc on a barge ( has this been covered in the forums archive.. must check)

I would happily buy an Ebay boiler but I am wary as my friend has just bought two 'duffs ' in a row, not a happy bunny. and I am not a heating engineer.

There is a seperate engine fuel oil tank already so thankfully one less tank to think about.

So it seems that more folk are considering a two fuel system, twice the instalation but not too bad a job and more flexibility in these times of rising, rising rising fuel costs.