Webasto Thermo 90/s/st

[Orca]

I would be very interested to hear from anyone who has a Webasto Thermo 90 and any variant S or ST fitted to their boat!?! Predominantly a 'bigger vessel', river cruiser fitment, but some bigger narrowboats also have been fitted with them. I would like to hear from anyone who has one fitted and how you service/repair them and how reliability has been?!?! Mine is a good unit and heats the boat in minutes, but it requires regular servicing and the parts prices are extortionate. This unit is vastly different to the more common Thermo Top C, to prevent any confusion.

Edited January 25, 2011 by Orca

[Orca]

Just to add, before I get all the usual replies about how 'a 9kw unit is far too big for any narrowboat and your servicing intervals will be reduced, due to it not working hard enough', well I know all that, but the thing does work very hard and I just choose to service it every three months regardless! I source my parts, where needed, from Turkey at a 30% reduction (Thermo Top C bits can be sourced also at similar reduction AFAIK). My point is, who else has one and how do you get on with it!!???

[Nickhlx]

Whilst I realise that the Thermo Top C is not like yours, I have run mine on kerosene ( home heating oil / 28 second) exclusively for 2 years and it hasn't needed a service / de-coke yet and is still in daily use as I speak. I chose to use this fuel as was told it was cleaner, would reduce servicing costs and as I have a domestic supply available at until now around 45p/litre, and so reduces running costs as well... To date they have been right .....

 

Nick

[Orca]

Yes; I run mine (albeit recently) on a mix of 50/50 Kerosene/Diesel, along with the main engine as both are fed from one tank. I have yet to strip it out and see how the burner tube/cartridge has faired; though I would wager a lot less 'coking' of the internals. What you need to clarify here is that Kerosene, in any real amount, is not really available to the average narrowboater, aside from buying it in 4 litre drums as 'lamp oil'. I get mine, as possibly you do, elsewhere. .

[Nickhlx]

Yes; I run mine (albeit recently) on a mix of 50/50 Kerosene/Diesel, along with the main engine as both are fed from one tank. I have yet to strip it out and see how the burner tube/cartridge has faired; though I would wager a lot less 'coking' of the internals. What you need to clarify here is that Kerosene, in any real amount, is not really available to the average narrowboater, aside from buying it in 4 litre drums as 'lamp oil'. I get mine, as possibly you do, elsewhere. .

 

Hi,

 

 

Yes, I suppose its not generally available, at least not as freely as petrol/diesel - We have oil-fired central heating, and have a 2200 litre tank, so it seemed crazy not to use it. The fuel distributors do sell it in 205 litre drums though, for those who could accept deliveries, or buy 3 drums ( from about £10 each on E-Bay) and have a minimum 500 litre delivery when needed.

 

Nick

[Guest]

There is a very good thread -

Here

[Old Son]

why would a 9Kw heater be too big for a narrow boat? My eberspacher is a Hydronic 10, it produces just over 9Kw when flat out.

[Orca]

why would a 9Kw heater be too big for a narrow boat? My eberspacher is a Hydronic 10, it produces just over 9Kw when flat out.

 

 

Amen to you mate!! I agree wholly; but a lot of 'experienced' peeps say otherwise.

[Jparry]

Mine also is a Hydronic 10 but have never serviced it although mine runs only on weekends and the odd week but I do run it in the summer for hot water also .I am frightened to say it has never missed a beat in the 5 years I have had the boat It will probably just die now I have praised it Joe

[granddad]

Hi I have a webasto thermo 90 s

Bloody good now. had it for 12 years - problems in last 3 years 300 to 500 per year repairs and service. took it to kpt gillingham he has test rig - he recognised i had a fan problem. He fitted a new fan £450 and burner £150. Turkey parts are ok but I didn't know why it was un reliable so didnt know what to refit.

He said the red diesel was glazing the burner and the fan was slow. He said change to white (ulsd) diesel and more important get a BIG load on the output. I increased the rads from 4kw to 10 kw (cost 300) and now all red is ulsd.

It has been good since. It must raise the temp from nil to 25c in 2 hours in a 60 foot nb.

I have set it up to be easy to take home and bench refit. The unit is easy to service, the parts arent expensive and its easy to refit in the boat.

I recommend it (now)

Ken

[Orca]

Hi I have a webasto thermo 90 s

Bloody good now. had it for 12 years - problems in last 3 years 300 to 500 per year repairs and service. took it to kpt gillingham he has test rig - he recognised i had a fan problem. He fitted a new fan £450 and burner £150. Turkey parts are ok but I didn't know why it was un reliable so didnt know what to refit.

He said the red diesel was glazing the burner and the fan was slow. He said change to white (ulsd) diesel and more important get a BIG load on the output. I increased the rads from 4kw to 10 kw (cost 300) and now all red is ulsd.

It has been good since. It must raise the temp from nil to 25c in 2 hours in a 60 foot nb.

I have set it up to be easy to take home and bench refit. The unit is easy to service, the parts arent expensive and its easy to refit in the boat.

I recommend it (now)

Ken

 

I'm currently building up a second unit using both parts from Turkey and good reusable 2nd hand parts I've sourced locally. The Burner Tubes are the most susceptible to failure, due to the central washer in the stainless steel tube fracturing under 'poor load' conditions. The heat insulating gasket in the alloy part of this component also fails in my experience, somewhat prematurely!?!

 

The Burner Cartridges themselves are much more useable over time with good maintenance and cleaning regularly and I have 3 or 4 of them I 'swap' after cleaning and certain hours of useage. As you say; a BIG ouput is key; and I always run it up now Summer or Winter on full output conditions; which I never used to do initially. Running a 50/50 Kero/Diesel mix I hope will help also!?! Mine will raise the temp to 25c in a 65ft boat in a lot less than 2 hours, as I suspect yours will!?! You say the parts 'aren't expensive'; though I just wondered on the back of that statement where you source your parts from?? This is currently my cheapest, 'new parts' price option, all inc VAT:

 

Burner Cartridge £135

Burner Tube £200

Water Pump £200

COmbustion Motor (fan) £200

Flame Sensor/Glow Pin £50 each

[Orca]

Before buying new, just thought I'd ask the question on here. Anyone got a spare ECU for a Thermo 90 they'd like to sell?? I suspect not, but it's always worth a try eh! As per below:

 

Edited May 16, 2013 by Orca

[mrsmelly]

We have a 90s on one of our boats at work. I service it but it does seem to take quite a lot of abuse. It is far too small for our needs but still manages to heat the toilets the far end of the cabin and gives loads of hot water. We run it straight from the red diesel tank. I changed the burner cartridge this year but it wasnt at all bad but its just a service part as far as we are concerned we then changed one sensor which had rotted and was shorting out. Seems a good bit of kit to me. I have the usual little unit on my own boat and that is giving sterling service. I think as with many things being in constant use is better for them, rather than wearing them out they seem to perform better than kit on hobby boats which quite often goes weeks or months without being used.

 

Tim

[Orca]

Hi Mrsmelly - I'm assuming the 90s your referring to is fitted to one of the boats in your sig picture!??! Would look a bit small on something like that certainly! The pair of 90 units I have (not 90s's) are now getting on a bit, but are still functioning as they should - with good servicing etc.. I have lots of spare bits I bought off of Concoform, but as I am now running on my spare ECU it's time to source a new one. Been a heck of a Winter for the old 'boiler' and the ECU gave out last week.

Edited May 16, 2013 by Orca

[smileypete]

Maybe try sending a PM to NMEA, possibly he could at least sort a service manual out for you if you don't have one.

 

Is it definitely the ECU? ISTR there's also diagnostic software for the Webasto if you don't have it already which could give more info.

 

If the old one's definitely kaput and will get chucked I'd at least try taking the can off and looking for dry solder joints and scorched components.

 

cheers, Pete.

~smpt~

[Orca]

Hi Pete - yep, defo the ECU! The heater all of a sudden shut down last week and then intermittently kept trying to fire up again - only to shut down after a few minutes. I have two of these heaters and two or more of each individual component; and today, before swaping the actual 'boiler' unit, I decided to swap the ECU first for the spare one I have. On this older T90 unit, the ECU is located and positioned separately - so I just swapped them over and hey presto the heater unit fired up without trouble. It's been on most of the afternoon and evening up until around 11pm with no fault. That said, in the past I have had either ECU not firing a particular unit up; but that problem turned out to be a sensor fault on the heater itself. But, yes, defo ECU here.

 

The diagnostic software is contained in the actual ECU isn't it??? I do have a full Workshop Manual for this type of unit, which has proven to be invaluable these past few years. Thanks for the heads up though.

Edited May 16, 2013 by Orca

[smileypete]

The diagnostic software is definitely separate, it's listed on the main dealer site but downloadable elsewhere:

 

http://www.techwebasto.com/heater_thermo_test.htm

http://micro.homelinux.net/~mjander/Eberspacher%20&%20Webasto%20Manuals/

http://www.carhelp.info/forums/showthread.php?t=48219

 

A trawl of the car forums that use the Webasto should turn up some info on how to use the software:

 

http://www.disco3.co.uk/wiki/Fuel_Burning_Heater

 

The software should hopefully at least give a diagnostic code for the problem. Also it looks like the air mixture can be tailored according to the install, so an ECU that's set up for one install might not work as well for a completely different install.

 

http://www.canalworld.net/forums/index.php?showtopic=53036&st=0

 

Still worth sending a PM to NMEA, he might be able to help of give some idea of common problems to look out for. A 9kW heater may be pretty oversized as it is, so any other issues won't help either.

 

cheers, Pete.

~smpt~

[Orca]

Many thanks for all the links Pete - I'll have a trawl through them over the course of the next few days. Always thought the software and associated fault codes were an integral part of the ECU (like the OBDII system in cars). In the T90 Workshop Manual I have, it gives the fault codes and the reasons and just states the ECU will flash up the associated code as a series of 'flashes' on the On/Off switch (it has an integral green light). Heater is working good now, with the replacement ECU on it. Put the old one back on yesterday (10 minute swap job) and it started to fire up, then suddenly shut down with a series of puffs of smoke and 'banging' noises coming from the water pipework.

[smileypete]

Sounds like there's no pump running with the old one, faulty pump output or connector? If you run the pump via manual control does it still do the same?

 

Might also be worth comparing the fan output voltage and maybe also the fuel pump pulse rate in case the old one is set up differently.

 

cheers, Pete.

~smpt~

Edited May 18, 2013 by smileypete

[Orca]

The ECU that was on my heater worked fine from the time when I bought the boat (April 08') and gave out last week. All the Concoform boats had the early Thermo 90 units fitted to them in the late 90's/early 00's and the ECU's were just the bog standard ones from Webasto as per everything else AFAIK. (Butler Technik's website currently has them for £320 inc): https://sales.butlertechnik.com/webasto/webasto-water-heater-spare-parts/thermo-90/webasto-control-unit-12v-thermo-90-24375a and if I purchased one of those it would just be a bolt on and go job.

 

But yes, it definately seems to be a water pump issue with the old ECU (telling it to shut down prematurely, which in turn shuts the fuel and heater off).

[Orca]

A very big thank you to 'Granddad' on here for selling me his Thermo 90S units. I have spent the last couple of days integrating a T90S wiring loom into an existing T90 harness. The heaters are the same, but the ECU's are a little different. I can now interchange between the older ECU (as pictured above) and the slightly newer T90S version (essentially the same, but flanged over the fan unit with different connections). I have run up two different heaters, on two different ECU's and they work fine on interchangeability. A nice challenging few days!

Edited March 7, 2014 by Orca

[NMEA]

That is an old analogue control rather than a solid state ECU, has no software codes, from memory that was introduced with the 90S, you say you service it? what is the last thing you confirm when it is re installed, if it's not the burn rate using an exhaust gas analyser all your hard work may have been wasted due to a rich burn coking the thing up or resulting damage to the burner tube washer from too lean a burn.

[Orca]

The burner tube washers were always a bit of a weak point imo - Concoform Marine had similar problems over a lengthy period, and they had all the relevant test/diagnostic equipment. The tube I'm on at the moment is on a third Winter (interchanged from another unit) so doing pretty good, though when inserted last November it had just started to crack across its surface, so come the Summer it will be stripped out and thrown. I always have the unit on full load where possible and never shut it down prematurely.

 

I hear what you are saying though and I realise you must get pissed off with DIY'ers like myself. I must add that I have very little coking now since using a kero/diesel mix. Can get a full two Winters out of one unit before stripping down and cleaning. With the old Gas Oil it was barely a half Winter and it would coke up. I have also shortened the exhaust which has helped.

Edited March 7, 2014 by Orca

[raymondh]

Hi,

We have a 90s on our boat - run since fitted on kerro, never been serviced or even taken apart! Its now clocked up around 5000 hours we have 7 rads, towel rail and cal adding up to around 11kw and is controlled by a 7 day timer and a domestic type room stat

I am paying around 70/80p litre at the moment for kerro as I only purchase in 25 litre drums

Regards Ray

[NMEA]

I hear what you are saying though and I realise you must get pissed off with DIY'ers like myself.

Certainly I would have no cause to be pissed off, in fact I am often impressed by the ingenuity and willingness of DIYers to have a go, often with satifactory if not ideal results. However what amuses (note not pisses off) me and a number of my colleagues is people who produce "how to" videos and instructions on how to service ( or as we call them how to half service") as if they were some kind of expert and the fawning that ensues, now that really is funny.