Webasto v's Eberspacher & Thermo Top C vs Evo 5?

[Malc_sh]

Hi,

Choosing a water heater for my 60' Sailaway NB. I've got a Thermo Top C on a sail boat currently which does a fine job but only heats water in an exchanger and the Calorifier. 

 

My questions are does anyone vote for Eberspacher over Webasto and if so why please? 

 

Assuming Webasto I'm struggling to see the benefits of the 'new' Evo 5 over the (I'm led to believe) discontinued Top C? Can anyone shed any light? 

 

I've read some stuff on the CO2 adjustment. Is that likely to be necessary? It's not something I've ever touched on the sailboat. 

 

Anything else I should consider, for 4 or 5 rads, heat exchanger then calorifier circuit? For ease I am thinking of buying a 'narrowboat kit' which seems to include most of the bits I'll need. I don't like Webasto's filter but it sounds like they are mandating their dealers to fit them now so I guess that's necessary.

 

thanks, Malc

[Tony Brooks]

Not sure what the heat exchager is for unless its a blown air "radiator". I suspect with five rads and calorifier you might be getting close to needing the larger pressure jet Webasto but NMEA, a fellow member ,could give good advice and chapter and verse. Pressure jet boilers seem to be more reliable than the normal Ebber/Mikuni/Webasto types.

 

 

[Malc_sh]

28 minutes ago, Tony Brooks said:

Not sure what the heat exchager is for unless its a blown air "radiator". I suspect with five rads and calorifier you might be getting close to needing the larger pressure jet Webasto but NMEA, a fellow member ,could give good advice and chapter and verse. Pressure jet boilers seem to be more reliable than the normal Ebber/Mikuni/Webasto types.

 

 

Thanks, I rather hope NMEA does come on, I've read their (his/her?) posts and they seem very knowledgeable. I don't understand a 'pressure jet boiler' but I've have a google and see. 

The heat exchanger is https://www.butlertechnik.com/installation-accessories-c63/webasto-motor-home-plate-heat-exchanger-with-mixer-valve-4111209a-p1516 - I have one on the sail boat. It's fabulous, within ten minutes (top c) you get unlimited amounts of hot water, bit like a combi boiler. Obviously the tank water is also getting heated. 

[Cas446]

The Evo 5 is a variable output of the Thermo Top V which has been fitted to many cars for many years. If you have an undersized radiator output in comparison to the heater output then the evo 5 may be better as it can power down without cycling. Although I have no idea what it's like in practice.

 

If you are a confident diy'er then you could fit a Thermo Top V from a Jaguar (ebay ~£40) webasto fuel pump from a Land Rover Disco 3 (ebay ~£30) Mikuni 22mm marine exhaust from the Mikuni website, webasto 1533 timer and a seperate circulating pump. The 1533 timer starts the heater via W-bus but also has an on/off output which you can drive a delayed drop off relay to run the circulation pump. Delayed off to allow for webasto cool down cycle. If you buy a TTV off eBay buy one with 20cm of loom to save buying any plugs. If you need plugs go to the Disco3 forum shop as they are very resonably priced. A separate circulation pump is useful so you can combine the system with a heat exchanger on the engine skin tank or calorifier circuit so you can use the waste heat from the engine when underway. You can still use the TTV to heat the calorifier by using a motorised valve which can be operated by the webasto itself as it helpfully has an output that turns on when it has heated the water to >40 deg. (Draw a diagram and you will see the issue) Others may warn that Webastos of eBay don't work. That's not my experience I have this set up and another one to heat the kids paddling pool!. TTV from Jaguars have 9v -16v operating range. Avoid TTV from Land Rover and VW as they have on board pump control - better to have separate more powerful pump. The default plug on TTV has outputs for fuel pump and car can-bus but you can move can-bus pins to W-bus and >40 deg output. The Disco 3 forum is mine of information on this. A few terminations and you are away. The rest of the fuel system bits can be bought from Mikuni website and follow BSS guidelines.  Job done.  Great fun enjoy. Ah and look on ebay for the heat exchangers supplied from Poland - great quality and 1/4 of the price you have linked to above.

 

[Tony Brooks]

32 minutes ago, Cas446 said:

The Evo 5 is a variable output of the Thermo Top V which has been fitted to many cars for many years. If you have an undersized radiator output in comparison to the heater output then the evo 5 may be better as it can power down without cycling. Although I have no idea what it's like in practice.

 

If you are a confident diy'er then you could fit a Thermo Top V from a Jaguar (ebay ~£40) webasto fuel pump from a Land Rover Disco 3 (ebay ~£30) Mikuni 22mm marine exhaust from the Mikuni website, webasto 1533 timer and a seperate circulating pump. The 1533 timer starts the heater via W-bus but also has an on/off output which you can drive a delayed drop off relay to run the circulation pump. Delayed off to allow for webasto cool down cycle. If you buy a TTV off eBay buy one with 20cm of loom to save buying any plugs. If you need plugs go to the Disco3 forum shop as they are very resonably priced. A separate circulation pump is useful so you can combine the system with a heat exchanger on the engine skin tank or calorifier circuit so you can use the waste heat from the engine when underway. You can still use the TTV to heat the calorifier by using a motorised valve which can be operated by the webasto itself as it helpfully has an output that turns on when it has heated the water to >40 deg. (Draw a diagram and you will see the issue) Others may warn that Webastos of eBay don't work. That's not my experience I have this set up and another one to heat the kids paddling pool!. TTV from Jaguars have 9v -16v operating range. Avoid TTV from Land Rover and VW as they have on board pump control - better to have separate more powerful pump. The default plug on TTV has outputs for fuel pump and car can-bus but you can move can-bus pins to W-bus and >40 deg output. The Disco 3 forum is mine of information on this. A few terminations and you are away. The rest of the fuel system bits can be bought from Mikuni website and follow BSS guidelines.  Job done.  Great fun enjoy. Ah and look on ebay for the heat exchangers supplied from Poland - great quality and 1/4 of the price you have linked to above.

 

I don't see anything there about getting the firmware reset to marine standards. This may or may not work. More likely not as the batteries age.

[Farey]

I've had a Thermotop C for 14 years, and it's very prone to cutting out if the battery voltage drops slightly (despite having good, well charged batteries). I talked to the dealer, and was told this was a problem using it on boats, but that the newer models had fixed the problem.

[Cas446]

18 minutes ago, Tony Brooks said:

I don't see anything there about getting the firmware reset to marine standards. This may or may not work. More likely not as the batteries age.

The Webasto diagnostic software displays the under and over voltage inhibit and they are 9v and 16v so I can't see this being a problem unless you have utterly knackered batteries. What you say may well apply to Thermo Top C of which I have no knowledge but this is Thermo Top V and the two units I have work fine. The one on the boat for 30 minute boosts, the one I use at home with the kids paddling pool rus for 250 ish minutes then stops as it has an in built maximum run timer. However I restart it and away it goes again. You may be right but this is not my experience with TTV from Jaguars. There is a guy on ebay who has made a pcb converting the W-bus to on/off. This is what I use with the paddling pool unit so it can be started with a light switch.

[Malc_sh]

12 hours ago, Farey said:

I've had a Thermotop C for 14 years, and it's very prone to cutting out if the battery voltage drops slightly (despite having good, well charged batteries). I talked to the dealer, and was told this was a problem using it on boats, but that the newer models had fixed the problem.

Interesting that it's fixed on newer models. My current sailboat, and the new NB will be 24v and therefore the heater gets it's 12v from a converter which means the voltage is rock solid regardless. Boat is also having lithium (again got them already, and once you've had it it's hard to go back to LA!). Cheers

12 hours ago, Cas446 said:

The Evo 5 is a variable output of the Thermo Top V which has been fitted to many cars for many years. If you have an undersized radiator output in comparison to the heater output then the evo 5 may be better as it can power down without cycling. Although I have no idea what it's like in practice.

 

If you are a confident diy'er then you could fit a Thermo Top V from a Jaguar (ebay ~£40) webasto fuel pump from a Land Rover Disco 3 (ebay ~£30) Mikuni 22mm marine exhaust from the Mikuni website, webasto 1533 timer and a seperate circulating pump. The 1533 timer starts the heater via W-bus but also has an on/off output which you can drive a delayed drop off relay to run the circulation pump. Delayed off to allow for webasto cool down cycle. If you buy a TTV off eBay buy one with 20cm of loom to save buying any plugs. If you need plugs go to the Disco3 forum shop as they are very resonably priced. A separate circulation pump is useful so you can combine the system with a heat exchanger on the engine skin tank or calorifier circuit so you can use the waste heat from the engine when underway. You can still use the TTV to heat the calorifier by using a motorised valve which can be operated by the webasto itself as it helpfully has an output that turns on when it has heated the water to >40 deg. (Draw a diagram and you will see the issue) Others may warn that Webastos of eBay don't work. That's not my experience I have this set up and another one to heat the kids paddling pool!. TTV from Jaguars have 9v -16v operating range. Avoid TTV from Land Rover and VW as they have on board pump control - better to have separate more powerful pump. The default plug on TTV has outputs for fuel pump and car can-bus but you can move can-bus pins to W-bus and >40 deg output. The Disco 3 forum is mine of information on this. A few terminations and you are away. The rest of the fuel system bits can be bought from Mikuni website and follow BSS guidelines.  Job done.  Great fun enjoy. Ah and look on ebay for the heat exchangers supplied from Poland - great quality and 1/4 of the price you have linked to above.

 

Many thanks, looks very interesting but a DIY step too far for this build I think. I'll look up the parts and info you mention though as I've not come across this before. When I've done my NB build I plan on converting my van into a camper so this could be the ticket on there  Cheers

[Malc_sh]

12 hours ago, Tony Brooks said:

I don't see anything there about getting the firmware reset to marine standards. This may or may not work. More likely not as the batteries age.

Tony, that's an interesting comment. What gets changed for marine standards? My attention was drawn to the CO2 measurements which is not something I've ever taken notice off with previous Air heaters or the current water heater. I am guessing it's set and forget but I wonder if it actually makes much difference? 

 

Cheers, 

[Tony Brooks]

1 minute ago, Malc_sh said:

Tony, that's an interesting comment. What gets changed for marine standards? My attention was drawn to the CO2 measurements which is not something I've ever taken notice off with previous Air heaters or the current water heater. I am guessing it's set and forget but I wonder if it actually makes much difference? 

 

Cheers, 

All I know is what I was told by a Webasto marine agent (Kings Lock). He said that marine units have different cut out voltage settings in their firmware and when ex vehicle units are fitted to boats without resetting the firmware there are problems.  After many years with old versions of Webastos on a hire fleet nothing would induce me to have one (or and Ebberkuni) so I have no personal experience but I have heard of too many instances of problems with ex vehicle units to discount what I was told. For clarity the Wenastos I dealt with are nothing like the modern ones. They had a sort of revolving fuel spraying burner assembly and a clockwork start up timer so nothing can be learned from them.