Webaso Thermo Top Z/C

[Jayman]

I pulled a webasto thermo top z/c out of a Rover 75 with the hope of using it for heating and hot water. (I can't afford the genuine marine version). It has the water pump attached so it should be the same as the thermo top C hardware-wise.

 

The problem I'm having is that once I've wired it up the combustion fan and water pump start then after about a minute the combustion fan stops then a little while later the water pump stops, the fuel pump doesn't run at all.

 

I put a light in place of the fuel pump and it stayed dimly lit constantly so it is an electrical problem not a fuel pump problem. The voltage across the fuel pump is about 8.9V, the voltage across the whole unit is 12.8V.

 

I have tried with two different heaters with two different looms and pumps. I have tried the connection from the power switch going into connection 1 and connection 3 as two different official webasto wiring diagrams had these two separate set ups.

 

My thought is that there must be something rover 75 specific about these heaters that I haven't figured out yet

 

any replies would be much apreciated

 

Jay

[gazza]

I had same problem with a BMW x5 unit.

 

The BMW used the vehicles canbus system to control the thermo top from its climate control, it needed a 5v signal to operate it.

 

I sent it to Jason at bk marine in napton, it ended up having a new board which was not cheap.

[Jayman]

Ah, I was hoping I would not need to buy a new board. There's no work around for this then? I can easily get more bits of rover, I just don't wan't half a car cluttering my space up.

[lynalldisocvery]

I had same problem with a BMW x5 unit.

 

The BMW used the vehicles canbus system to control the thermo top from its climate control, it needed a 5v signal to operate it.

 

I sent it to Jason at bk marine in napton, it ended up having a new board which was not cheap.

 

 

Gazza how much was a board?

 

Ta

Lynall

[gazza]

Can't remember now, I guess it was a good 150 plus, I had a loom and a fair few other bits off him. He set it up on the bench and test run it before I had it back.

My cheap webasto ended up being not as cheap as I had hoped.....

 

I didn't look into a work around, couldn't be arsed with sorting a 5v circuit and working out what inputs it needed to get it going. I am a nuts and bolts man with a smattering of lectrics.

[The Ents]

Hi Jay,

 

I have one of these units from the Rover 75 as reserve central heating on Balthazar.

The manual is available as a pdf file free on:

 

http://www.techwebasto.com/heater_main/907512.pdf

 

Most helpful. To test the fuel pump, connect and disconnect a 12v supply to the pump. each time the supply is raised to 12v the pump should make one Tick and a tiny tiny pulse of fuel should be expelled.

 

When you give pin 3 12v, the unit should start to purge with the air fan, then as the fan slows the fuel pump should start to tick, ie the volts on pin 3 should cycle 0v to 12v and back to 0v maybe once per second. If this does not occur the unit will cycle off beccause it will detect a flame out.

 

In the manual there are details of the internal connections to the glow plug, and this is where I would be testing next, but you do have to dismantle the unit.

 

The unit works very well on our bowt, but I found the integral water pump was not strong enough and I had to fit an auxilliary circulation pump, without it the unit would go into a water overheat lock out after an hour or so.

 

Good luck!

 

Mike.

[The Ents]

Hi again.

 

Just engaged brain.

 

The unit will not start to run if the water is above 30 centigrade at switch on.

 

The unit goes into a lockout after 3 unsuccessful starts. to clear the lockout see the manual 6:3, "Heater lockout reset Procedure"

 

Good luck,

 

Mike.

[NMEA]

With a complete marine kit reduced in price this January I really can't understand why people use vehicle heaters, they have quite a number of differences and just wind up causing grief, whitnessed by this thread and others on this and many other forums. I ask myself why my installs have a non invasive service once a year in September and even seven and eight year old ones are still OK, but I only ask once because the answer is simple, the correct kit, properly installed and the end user correctly informed and prepared on how to use the thing and what can realistically expected from it. Too may "my mate down the canal" and other inferior installs generally give these things a bad name, but it gives me loads of work sorting them out so I shouldn't complain. Not that this applies to anybody here of course. Don't expect the wrong thing poorly installed and serviced to do the right job or you will never be satisfied.

[Jayman]

With a complete marine kit reduced in price this January I really can't understand why people use vehicle heaters, they have quite a number of differences and just wind up causing grief, whitnessed by this thread and others on this and many other forums. I ask myself why my installs have a non invasive service once a year in September and even seven and eight year old ones are still OK, but I only ask once because the answer is simple, the correct kit, properly installed and the end user correctly informed and prepared on how to use the thing and what can realistically expected from it. Too may "my mate down the canal" and other inferior installs generally give these things a bad name, but it gives me loads of work sorting them out so I shouldn't complain. Not that this applies to anybody here of course. Don't expect the wrong thing poorly installed and serviced to do the right job or you will never be satisfied.

 

I am using a vehicle heater because it cost a tenner, if you can provide me with a full marine kit for even ten times that I would snap it up, but somehow I feel that its not going to happen. I have very little money to spend, but I have plenty of time and marine engineering experience. Its just a case of using what I've got.

[NMEA]

I am using a vehicle heater because it cost a tenner, if you can provide me with a full marine kit for even ten times that I would snap it up, but somehow I feel that its not going to happen. I have very little money to spend, but I have plenty of time and marine engineering experience. Its just a case of using what I've got.

 

I can supply you one for a fiver if you like, it won't work either, no point in using what you've got, now mater how gifted and ametuer you are if it is not the right component. Wrong ECU which requires input from the vehicle to operate can be made to work as a stand alone quite simply only if you know the produt intimately.

Edited February 14, 2013 by NMEA

[Jayman]

Hi Jay,

 

I have one of these units from the Rover 75 as reserve central heating on Balthazar.

The manual is available as a pdf file free on:

 

http://www.techwebasto.com/heater_main/907512.pdf

 

Most helpful. To test the fuel pump, connect and disconnect a 12v supply to the pump. each time the supply is raised to 12v the pump should make one Tick and a tiny tiny pulse of fuel should be expelled.

 

When you give pin 3 12v, the unit should start to purge with the air fan, then as the fan slows the fuel pump should start to tick, ie the volts on pin 3 should cycle 0v to 12v and back to 0v maybe once per second. If this does not occur the unit will cycle off beccause it will detect a flame out.

 

In the manual there are details of the internal connections to the glow plug, and this is where I would be testing next, but you do have to dismantle the unit.

 

The unit works very well on our bowt, but I found the integral water pump was not strong enough and I had to fit an auxilliary circulation pump, without it the unit would go into a water overheat lock out after an hour or so.

 

Good luck!

 

Mike.

 

Cheers mike, I've read about 5 diferent manuals cover to cover. I forgot to say I had already tested the pumps from both heaters.

 

So just to get what you wrote straight, the unit you have is straight from a rover 75, no modifications? the voltage drop across pin 3 and earth should be cycling between 0 and 12V?

 

I'm not sure it will be the glow plug as on both heaters the fuel pump does not operate at all when I try to start the system and like I said the pump voltage is a contant 8.9 volts, no clicking.

 

I can supply you one for a fiver if you like, it won't work either.

 

Hey, If I get enough thad don't work surely I couuld cobble something together. maybe not a heater, possibly some sort of modern art, the concept of the art being the irony of the sale of this broken heater art paying for a working heater.

[NMEA]

Hey, If I get enough thad don't work surely I couuld cobble something together. maybe not a heater, possibly some sort of modern art, the concept of the art being the irony of the sale of this broken heater art paying for a working heater.

 

Rather deep for a Thursday evening, but I guess if you found the right Hoxtonite or Islingtonite you could wind up with a new custom built boat let alone heater.

[smileypete]

My thought is that there must be something rover 75 specific about these heaters that I haven't figured out yet

 

any replies would be much apreciated

 

Jay

Have a look on some car forums where these are used, might get some good leads.

 

http://www.the75andztclub.co.uk/forum/showthread.php?t=12192

http://www.defender2.net/forum/topic14809.html

http://www.the75andztclub.co.uk/forum/showthread.php?t=71982

http://xdrivers.co.uk/forum/index.php?topic=5001.0

 

Also have a trawl if this forum to find out the usual problems, run the heater up on a bench with fresh road diesel and decent 12V batt on charge.

 

cheers, Pete.

~smpt~

[gazza]

I can supply you one for a fiver if you like, it won't work either, no point in using what you've got, now mater how gifted and ametuer you are if it is not the right component. Wrong ECU which requires input from the vehicle to operate can be made to work as a stand alone quite simply only if you know the produt intimately.

 

Which is why I shipped mine off to bk marine....... I hadn't considered the differences when eBay feever struck, but having said that, it was still significantly cheaper than buying a so called marine kit, the bits that make up the difference between a vehicle and marine kit don't add up to the vast premium attached by most vendors.

 

As for the install, meat n potatoes for me ;-)

 

I have a wallas d40 to fit soon, now there's a quality bit of kit compared to ebbers and webastos....

[NMEA]

 

I have a wallas d40 to fit soon, now there's a quality bit of kit compared to ebbers and webastos....

 

Not so sure, being both a Webo and Wallas dealer I have no axe to grind either way but the quality is no better, they still coke up if the CO2 isn't right. They also are quite large Kw for Kw which can make installs difficult. Very quiet though, which for some people is the only reason to buy one.

[gazza]

Not so sure, being both a Webo and Wallas dealer I have no axe to grind either way but the quality is no better, they still coke up if the CO2 isn't right. They also are quite large Kw for Kw which can make installs difficult. Very quiet though, which for some people is the only reason to buy one.

 

Much better and simpler construction, easier access for servicing if installed with a bit of thought no need to remove unit to get at burner chamber, glow plug 6 quid from motor factors, quiter so less likely to grind sueb gears :-)

 

not sure were you are going with coking as it is part of the service requirement of all oil fired heaters to be cleaned and inspected periodically. Although not a dealer I get to play with all three in various installs (only 3 are boat installs) and from a purely engineering standpoint the wallas is the better quality bit of kit.

 

You are correct in that a d40 is larger than a d4 eberspacher, problem on a lorry, ambulance, motorhome or coach. Not or shouldn't be a problem on a good sized boat which is what they are really meant for.

 

Still way over priced for what it is though....

[The Ents]

Cheers mike, I've read about 5 diferent manuals cover to cover. I forgot to say I had already tested the pumps from both heaters.

 

So just to get what you wrote straight, the unit you have is straight from a rover 75, no modifications? the voltage drop across pin 3 and earth should be cycling between 0 and 12V?

 

I'm not sure it will be the glow plug as on both heaters the fuel pump does not operate at all when I try to start the system and like I said the pump voltage is a contant 8.9 volts, no clicking.

 

 

 

Hey, If I get enough thad don't work surely I couuld cobble something together. maybe not a heater, possibly some sort of modern art, the concept of the art being the irony of the sale of this broken heater art paying for a working heater.

Hi Jay,

 

The unit I have is from an MG ZT, which is the same as the Rover 75. i have no modifications to the system from thee vehicle excepting a 7 day timer in the feed to pin 3.

 

I had a typo in my last post. The pin 3 is the signal to go wire, which needs constant 12v to run the unit. After the initial purge the fuel pump feed, pin 6 should start to pulse 0v-12v-0v to drive the fuel pump. If this is not happening you need to interrogate the unit using the diagnostic software, I guess. This is where yyou need the assistance of a professional with the right gear. Not very helpful I'm afraid, but do not give up on the idea. I was lucky enough for my unit to work "out of the box" or should I say out of the scrapyard. Good luck,

 

Mike.

[Jayman]

I thought that's what you meant mike.

 

Cheers to all for your replies. Just as an experiment I'm trying to make my own control board for my spare heater using an micro controller, some servo controllers and some other bits. May be a cheap fix, will probably just blow it up. I have information regarding voltages, pump frequency and sensor resistance. If it works perfectly I will probably post it somewhere.

 

anyway thanks again.

 

Jay

[vivelo]

This old topic came up whilst trying to find some info on a Webasto, but I might be able to answer the issue here, The rover 75 or BMW version which are the same (same wiring etc) uses the Climate control unit inside the car and that uses a thermostat which is in the front bumber. The unit is only designed to kick in if exterior temp is 10c or below. I'm not sure of a work around, but its fundamentally missing a switch which would be the climate control unit. I read how it works as I was fitting a remote control unit in one so the car interior will be warm before getting in.

Maybe bridging the wires that would go to the climate control unit will make it work, or use these wires as the on off switch.