Can I use the webasto when the engine is running?

[Top cat]

Our system has its fuel feed teed off the engine fuel feed and it works just fine with the engine running but we don't make a habit of it.

Top Cat

[Markinaboat]

One reason depending on how things are plumbed could be because the engine is heating the calorifier and possibly any radiators and therefore the Webasto will go into a cycle of stopping and starting.

 

When the water arriving into the Webasto is already at a hot enough temperature the Webasto thinks it has done enough and goes into shut down mode. As soon as it has shut down it starts up again. I remember reading on here that this cycling activity is not good for it.

BUMP!

[OldGoat]

Top cat, on 07 Apr 2016 - 6:34 PM, said:

Our system has its fuel feed teed off the engine fuel feed and it works just fine with the engine running but we don't make a habit of it.

Top Cat

 

The same on mine. I could never understand - given that the pipes are sized correctly, 8 or 10mm for the main feed and 3mm for the heater, and that the heater taps off before the engine - why that is wrong?? The heater only sips fuel and (relatively) so does the engine. Both are buffered by their filters.

 

(OK - mebe I should have two feeds - but the hull builder only provided and I can't get to the top of the tank easily.

 

Anyone got a reasoned why it's incorrect for a narrowboat with a 50HP engine

[Theo]

A normal installation on a modern narrowboat will have a coil from the engine heating the calorifier, and a coil from the eberspacher/webasto/mikuni heating the calorifier and generally heating some radiators in that circuit. The units do not especially like to heat JUST the calorifier and it is normal to leave a single (bathroom or towel rad) open in summer to take some heat.

individual boats might be designed by their owners to operate differently - someone who cruises a lot all year round may have the radiators heated by the engine for example.

my experience is not only my own boat, which has been in place for 14 years and used almost daily for 9 and now replaced this week, but also looking at all the boats coming into the workshop who have issues and talking to eberspacher/webasto service agents who deal with faults daily.

All has become clear. Many thanks.

 

I note that the Eberspacher and Webasto are much criticised here. Is the Mikuni better? Mine is generally OK.

 

Nick

[Theo]

One reason depending on how things are plumbed could be because the engine is heating the calorifier and possibly any radiators and therefore the Webasto will go into a cycle of stopping and starting.

 

When the water arriving into the Webasto is already at a hot enough temperature the Webasto thinks it has done enough and goes into shut down mode. As soon as it has shut down it starts up again. I remember reading on here that this cycling activity is not good for it.

We never have the engine and the Mikuni on at the same time. The waste engine heat is effectively free and heats the whole boat and the calorifier nicely when cruising in winter. We only use the Mikuni first thing in the morning for shaving water and washing up and to warm the boat before getting up. Before starting the engine I divert the water from the Mikuni into the engine block for about five minutes, then turn it off wait for purging and then start the engine. Starts beautifully on a frost morning without using the glow plugs.

 

The disadvantage is that I need to be very aware of the state of the valves. I can, through incompetence, leave the Mikuni with no water circulation. This is not a good thing. If I lend the boat to anyone I remove the valve wheel and leave it open.

 

Nick

[OldGoat]

Theo, on 07 Apr 2016 - 8:32 PM, said:

We never have the engine and the Mikuni on at the same time. The waste engine heat is effectively free and heats the whole boat and the calorifier nicely when cruising in winter. We only use the Mikuni first thing in the morning for shaving water and washing up and to warm the boat before getting up. Before starting the engine I divert the water from the Mikuni into the engine block for about five minutes, then turn it off wait for purging and then start the engine. Starts beautifully on a frost morning without using the glow plugs.

 

The disadvantage is that I need to be very aware of the state of the valves. I can, through incompetence, leave the Mikuni with no water circulation. This is not a good thing. If I lend the boat to anyone I remove the valve wheel and leave it open.

 

Nick

 

Ahem - but that's because (I assume you only have one coil ) and not because you can't run both together - which you could if there was a coil for each?

 

 

Theo, on 07 Apr 2016 - 8:13 PM, said:

All has become clear. Many thanks.

 

I note that the Eberspacher and Webasto are much criticised here. Is the Mikuni better? Mine is generally OK.

 

Nick

 

Well I (obviously) think so. Partly because of comments around at the time I was fitting out and more importantly because the importers knew the product, sold it to other than boat users, were knowledgeable and enthusiastic (in a 'engineering' way) about what they sold.

The principal competition was the ebersplutter with its history sold by salesmen at dealers - who knew nothing.

 

Result - a no brainer.

 

I installed it as per instructions - except for the feed and its been working well for 15+ years

[NMEA]

 

The same on mine. I could never understand - given that the pipes are sized correctly, 8 or 10mm for the main feed and 3mm for the heater, and that the heater taps off before the engine - why that is wrong?? The heater only sips fuel and (relatively) so does the engine. Both are buffered by their filters.

 

(OK - mebe I should have two feeds - but the hull builder only provided and I can't get to the top of the tank easily.

 

Anyone got a reasoned why it's incorrect for a narrowboat with a 50HP engine

Thing is that the evaporator type heaters specify 2mm bore, by tapping the engine feed or filter, let's say 8mm then part of the feed is not 2mm but 8mm and this can affect the life of the dosing pump. The fact that you can not get to the top of the tank is not a barrier, it takes me about 10 minutes to install a 2mm bore dip tube through a tank wall, you will find that's where your engine feed is taken from too I imagine. Sometimes it is OK, but you have to understand why it's OK, for instance if there is always a slight positive head at the tap then all will be fine and that's why it works for some installs and not others. Safer and better to install a dip tube properly terminating above the engine take off as there is also the potential to take enough fuel from the tank to leave you with no engine or reduced range, something I have seen on more than one occasion.

Edited April 8, 2016 by NMEA

[NMEA]

All has become clear. Many thanks.

 

I note that the Eberspacher and Webasto are much criticised here. Is the Mikuni better? Mine is generally OK.

 

Nick

No better and no worse really, I have agency for both so have no axe to grind and see issues with them all on a daily basis, other than the Mikuni is more power hungry being old coil wound glow plug technology and a bit agricultural (not a bad thing, it just is) , and of course it was (before being discontinued) cheapest of the lot and it still has the cheapest parts which was a major factor in many fit outs.

Edited April 8, 2016 by NMEA

[Theo]

No better and no worse really, I have agency for both so have no axe to grind and see issues with them all on a daily basis, other than the Mikuni is more power hungry being old coil wound glow plug technology and a bit agricultural (not a bad thing, it just is) , and of course it was (before being discontinued) cheapest of the lot and it still has the cheapest parts which was a major factor in many fit outs.

 

There is a replacement for the Mikuni, isn't there? I think that I read that it will fit in the space of the old one. Is it any better? What sort of system does it use?

 

N

[OldGoat]

NMEA, on 08 Apr 2016 - 6:41 PM, said:

Thing is that the evaporator type heaters specify 2mm bore, by tapping the engine feed or filter, let's say 8mm then part of the feed is not 2mm but 8mm and this can affect the life of the dosing pump. The fact that you can not get to the top of the tank is not a barrier, it takes me about 10 minutes to install a 2mm bore dip tube through a tank wall, you will find that's where your engine feed is taken from too I imagine. Sometimes it is OK, but you have to understand why it's OK, for instance if there is always a slight positive head at the tap then all will be fine and that's why it works for some installs and not others. Safer and better to install a dip tube properly terminating above the engine take off as there is also the potential to take enough fuel from the tank to leave you with no engine or reduced range, something I have seen on more than one occasion.

 

My bad - 3mm was a guess - I fitted whatever those nice gentlemen at Mikuni supplied.

Nonetheless many thanks for you comments - I take your point about the dosing pump, now I'm beginning to understand (I think...)

NMEA, on 08 Apr 2016 - 6:56 PM, said:

No better and no worse really, I have agency for both so have no axe to grind and see issues with them all on a daily basis, other than the Mikuni is more power hungry being old coil wound glow plug technology and a bit agricultural (not a bad thing, it just is) , and of course it was (before being discontinued) cheapest of the lot and it still has the cheapest parts which was a major factor in many fit outs.

 

Yes the wretched thing does appear to take a lot of current. I say 'appear' as my aged battery monitor insists it's taking 503 (yes) amps until the unit fires, which can't bet true as it's protected by a 25amp MCB.... Like most boaters fixing it is about having a supply of round tuits plus enthusiasm...

 

Always good to throw things in as what comes back can be very helpful and enlightening ('tis what these fora used to be about....)

[OldGoat]

 

There is a replacement for the Mikuni, isn't there? I think that I read that it will fit in the space of the old one. Is it any better? What sort of system does it use?

 

N

 

The old Mikuni folks have set up a new website to deal with the replacement:-

http://mvheating.co.uk/heater-kits/water-heater-kits/mv-hydro-5.html

 

which frightens me as it looks like an ebersplutter.

It was explained to me that by buying direct from whom ever, they could give a good price and the replacement costs a lot less than I paid for the MX40 - and that was several years ago.

 

Once an outfit give me good service and shows that they know what they are talking about - then I tend to stick with them - until I know otherwise. Apart from that I have no idea whether the units are good or not.

You can still get parts for the MX** units from the same place - it's complete units that are not available.

[NMEA]

 

There is a replacement for the Mikuni, isn't there? I think that I read that it will fit in the space of the old one. Is it any better? What sort of system does it use?

 

N

Yes, Steve (Mikuni UK) does the Hydro which is an Eber clone with some modifications, I have installed some as direct replacement for uneconomically repairable Mik'is and new installs, not a bad heater at all and of course has Mikuni UK back up and warranty. An exchange service is available which makes them a direct swap over for end of life MX40 heaters. Parts are very economical when the time comes.

[OldGoat]

NMEA, on 09 Apr 2016 - 09:10 AM, said:

Yes, Steve (Mikuni UK) does the Hydro which is an Eber clone with some modifications, I have installed some as direct replacement for uneconomically repairable Mik'is and new installs, not a bad heater at all and of course has Mikuni UK back up and warranty. An exchange service is available which makes them a direct swap over for end of life MX40 heaters. Parts are very economical when the time comes.

Does that mean its startup current is much less than the Mikuni?

[NMEA]

Does that mean its startup current is much less than the Mikuni?

I have not had one on my test rig yet as have not had the need so can't give you real world numbers but being pulsed power and ceramic glowpin technology just like the Webasto I would say it's a pretty safe bet, Those old coil wound plugs really rip current compared to any of the ceramics I have measured.

[OldGoat]

NMEA, on 10 Apr 2016 - 09:07 AM, said:

I have not had one on my test rig yet as have not had the need so can't give you real world numbers but being pulsed power and ceramic glowpin technology just like the Webasto I would say it's a pretty safe bet, Those old coil wound plugs really rip current compared to any of the ceramics I have measured.

Thanks for that - I'll have to wait until The Awful Day of Judgement - when my MX40 becomes BLR or I give up boating to resolve that point.

OR I could get off my fundament and give them a bell!

[Markinaboat]

We changed boat last November and it has a Webasto Thermo Top C installed. I don't think it had much use in it's first 18 months but it's been on constantly (on timer) since November. I'm tech savvy so would do any required work myself unless of course there was a fault that I couldn't identify.

 

It may be that during the summer with the rad circuit isolated, I occasionally want to make hot water when the engine or genny (for immersion) haven't been running, so my questions are:

 

1) Are the Webastos so bad (after a period of recycling) that they are unserviceable?

 

2) once it needs decoking and/or parts replacing, what is the cost likely to be?

 

Thanks

[smileypete]

We changed boat last November and it has a Webasto Thermo Top C installed. I don't think it had much use in it's first 18 months but it's been on constantly (on timer) since November. I'm tech savvy so would do any required work myself unless of course there was a fault that I couldn't identify.

 

It may be that during the summer with the rad circuit isolated, I occasionally want to make hot water when the engine or genny (for immersion) haven't been running, so my questions are:

 

1) Are the Webastos so bad (after a period of recycling) that they are unserviceable?

 

2) once it needs decoking and/or parts replacing, what is the cost likely to be?

 

Thanks

 

Maybe just fit a cylinder thermostat to switch off the webby just before the point it starts to cycle.

 

Much depends on whether it's a decent install from a Webasto trained installer, or as good as. Would have thought they would fit a cylinder thermostat as a matter of course.

[NMEA]

We changed boat last November and it has a Webasto Thermo Top C installed. I don't think it had much use in it's first 18 months but it's been on constantly (on timer) since November. I'm tech savvy so would do any required work myself unless of course there was a fault that I couldn't identify.

 

It may be that during the summer with the rad circuit isolated, I occasionally want to make hot water when the engine or genny (for immersion) haven't been running, so my questions are:

 

1) Are the Webastos so bad (after a period of recycling) that they are unserviceable?

 

2) once it needs decoking and/or parts replacing, what is the cost likely to be?

 

Thanks

Problem with doing that is, the circulated coolant volume can be reduced to such a level that the heater is capable of raising the return coolant temperature very quickly despite the calorifier being quite a good heat sink, including the bathroom towel radiator in the circuit can help somewhat but not always. This can and does often happen before the calorifier is up to temperature and causes reduction in output and cycling. Fitting a cylinder ‘stat will not help in these circumstances as it will not kick in before the heater cycles. The best thing to do in your circumstances is to ensure the coolant volume is sufficient to prevent the return temperature getting too high. If you make sure the heater is set up correctly with a nice clean burn it will be a huge help, probably more so than any other factor. A new burner is around £230 at retail and replacing labour time and resetting the CO2 after doing it would take about 90 minutes for an easy one if no problems with purging air present.

Edited April 12, 2016 by NMEA

[Markinaboat]

Thanks - so it's a case of a new burner as opposed to decarbonising/cleaning after regular cycling?

 

The coolant volume is going to be limited by the existing plumbing if I close off the radiator loop and would not want the bathroom rad on as no opening windows/hatches (Plan on fitting a pigeon box in due course).

 

So how long a period of recycling before a likely issue occurs, are we talking just a weeks use or maybe 2/3 months?

[NMEA]

Thanks - so it's a case of a new burner as opposed to decarbonising/cleaning after regular cycling?

 

The coolant volume is going to be limited by the existing plumbing if I close off the radiator loop and would not want the bathroom rad on as no opening windows/hatches (Plan on fitting a pigeon box in due course).

 

So how long a period of recycling before a likely issue occurs, are we talking just a weeks use or maybe 2/3 months?

Depends on how well the burner is set up, how often you do it, if you give a full burn from time to time etc but months rather than weeks and possibly as much as a year or more.

[Markinaboat]

Depends on how well the burner is set up, how often you do it, if you give a full burn from time to time etc but months rather than weeks and possibly as much as a year or more.

sounds ok then as would most likely only be once a week for a few weeks with the rest of the year/winter the heating being on

[NMEA]

sounds ok then as would most likely only be once a week for a few weeks with the rest of the year/winter the heating being on

Should be perfectly fine with that, they need to be run for 30 minutes or so a month even in the summer months to keep fresh fuel in the lines, prevent sticky bearings etc anyway.

[Theo]

Ahem - but that's because (I assume you only have one coil ) and not because you can't run both together - which you could if there was a coil for each?

I have two but only one is connected. That was as it was when I bought the boat.

 

Well I (obviously) think so. Partly because of comments around at the time I was fitting out and more importantly because the importers knew the product, sold it to other than boat users, were knowledgeable and enthusiastic (in a 'engineering' way) about what they sold.

The principal competition was the ebersplutter with its history sold by salesmen at dealers - who knew nothing.

 

Result - a no brainer.

 

I installed it as per instructions - except for the feed and its been working well for 15+ years

Mine is very much not installed according to instructions, so NMEA tells me, but it works as it is so I am unwilling to make huge changes.

Edited April 14, 2016 by Theo

[Theo]

Ahem - but that's because (I assume you only have one coil ) and not because you can't run both together - which you could if there was a coil for each?

I rather think that I could run them both together even with the engine and the Mikuni connected to the same coil, but I don't choose to. If I have the engine running that is a perfectly good heat source and I don't need the Mikuni. I use the Mikuni only if the engine is not running.