Webasto not working

[RosieR]

Hi there! I’ve just moved onto a boat with a webasto system (well an MV hydro 5-S) for some reason it cuts out after a minute or 2. The heating system runs through all open radiators and hot water. I leave 1 radiator open and it starts to warm up but the hot water won’t turn on! The pump and battery amps are fine. Does anyone have any advice how to fix it? If not, does anyone know a mechanic or engineer who would be able to come and have a look? I’m currently moored in Harefield.

Thank you! 

[Tracy D'arth]

Air lock on the calorifier circuit?  You need more than one rad open otherwise there is not enough flow for the burner to get rid of the heat and it will shut down.

Does it still do it with the engine running and charging? Batteries all good and charged?

[RosieR]

Thanks for that, I’ll try the air lock and opening another radiator. The batteries are on 13 so it shouldn’t need to engine but I’ll try and run it and see if it helps. Thanks again! 

[matty40s]

The voltage saying 13v at the batteries doesnt mean that the voltage at the Webasto is 13. 

Especially at startup, the units draw a lot of power, and if your batteries are tired/sulphated or not properly charged, or the wires to the Webasto not thick enough, then the unit may think theres not enough power and shut down.

[RosieR]

That makes a lot of sense! Should I try running the engine before?

[matty40s]

Run it while it's starting up, if it gets past the stage where its been cutting out successfully, then you know its probably voltage related.

If not, it's more likely airlock in water or fuel system. 

When was the last time the system worked properly?(days, weeks, months or years).

[RosieR]

Less than a week ago it was working, only in the past 4 days or so it’s been a problem 

[Onewheeler]

If it's getting to the point of starting to warm up it's probably not battery related. Peak current is in the first minute or so, about 20 A, thereafter it won't go much over 10 A. Any clouds of white smoke?

[Mad Harold]

Has it run out of fuel,and on refilling got air in the fuel pipe?

[Tony Brooks]

Or if it has  a header tank does it have enough water/antifreeze mixture in it?

 

If its a totally sealed system with an expansion vessel (not the one that may be on the domestic water system) does it still have pressure and if not it needs topping up.

Edited May 20, 2021 by Tony Brooks

[RosieR]

No clouds of white smoke in the engine room, I didn’t see any from the exhaust either. It takes its fuel from my tank which is nearly full, I have been advised it could be an airlock in the fuel pipe 

[Tony Brooks]

Just now, RosieR said:

No clouds of white smoke in the engine room, I didn’t see any from the exhaust either. It takes its fuel from my tank which is nearly full, I have been advised it could be an airlock in the fuel pipe 

 

Doubtful if you are getting some heating. It sounds much more like an overheat shutdown.

[Tracy D'arth]

1 minute ago, RosieR said:

No clouds of white smoke in the engine room, I didn’t see any from the exhaust either. It takes its fuel from my tank which is nearly full, I have been advised it could be an airlock in the fuel pipe 

Can you hear the fuel pump clicking?

[RosieR]

3 minutes ago, Tony Brooks said:

Or if it has  a header tank does it have enough water/antifreeze mixture in it?

 

If its a totally sealed system with an expansion vessel (not the one that may be on the domestic water system) does it still have pressure and if not it needs topping up.

It’s not a pressurised system and I filled it up fully when it started having problems (about 5 days ago), thank you for offering advice 

[RosieR]

7 minutes ago, Tracy D'arth said:

Can you hear the fuel pump clicking?

It starts to whir, it gets loader and loader , it sounds like it’s trying to pump something round then it just stops 

9 minutes ago, Tony Brooks said:

 

Doubtful if you are getting some heating. It sounds much more like an overheat shutdown.

That makes sense! Do you know what the culprit could be for over heating?

[Tracy D'arth]

The fuel pump should click not whir.  The blower motor whizzes/whirs

[Tony Brooks]

8 minutes ago, RosieR said:

It starts to whir, it gets loader and loader , it sounds like it’s trying to pump something round then it just stops 

That makes sense! Do you know what the culprit could be for over heating?

 

Assuming the Webasto water circulation pump is still running as said its more likely to be an airlock in a pipe. Often the pipes leave the Webasto horizontally and the drop down to cabin floor level. This means that any air in the system can get trapped in the pipes around the Webatot. It's worse if the horizontal pipe have a slope on them. Air will tend to collect at the highest point.

 

The 1960s Webastos I know had the circulation pump built in but I am not sure about modern ones. It might be a separate unit, if so you should be able to hear or feel it vibrating if its running.

[Cheshire cat]

Mine makes the whirring noise when i have been messing with it (changing the antifreeze) and have introduced an air lock near the webasto. The solution is to pull off a hose at the webasto and get rid of the air. 

 

I am a bit puzzled as to why this has only started happening in the last week.

[enigmatic]

Have you tried the fuse reset (read your manual) yet?

 

Mine is very temperamental in terms of starting and then stopping within 2min at even moderately low voltages, but not at 13v!

[Mike Miller]

Hi I have just bought a Narrowboat and was told the webasto was working. Did not check because it was very hot last week.  Now I need to switch it on but all I get is a flashing display no sounds or and other indication its working.  When I pusj the start/heat button on display it light up red for 10 seconds then gooes out. Any suggestion

Tjanks

Mike

[Sir Nibble]

I have to say, and apologies to the people with problems,  but heater problems in June. Welcome to England. 

[matty40s]

11 hours ago, Mike Miller said:

Hi I have just bought a Narrowboat and was told the webasto was working. Did not check because it was very hot last week.  Now I need to switch it on but all I get is a flashing display no sounds or and other indication its working.  When I pusj the start/heat button on display it light up red for 10 seconds then gooes out. Any suggestion

Tjanks

Mike

Charge your batteries is the 1st thing to check, then water levels in system, and then fuel....

[Alan de Enfield]

11 hours ago, Mike Miller said:

Hi I have just bought a Narrowboat and was told the webasto was working.

 

Maybe contact the seller and ask him to show / tell you how to make it work.

Was it a private (face to face) purchase or via a broker ?

Did you have a survey ? Did surveyor 'mark' is as working ?

[Timx]

Check you have not put a fender over the exhaust, if so it will start up then shutdown.

[Tony Brooks]

18 minutes ago, Timx said:

Check you have not put a fender over the exhaust, if so it will start up then shutdown.

Or moored with the exhaust tight against a bank or another boat.