Webastow woes

[Phil Hill]

Hello all. 

So I've got a Webastow evo top, installed on a Collingwood widebeam. Boat and Webastow are 3 years old. 

I've had constant issues with the heater. In the 3 years I've replaced the burner, temp sensors and the heat exchanger. 

The issue I'm having now is the unit goes through start up fine. Runs for around 30 mins then shuts down. There's a heavy smell of diesel. There is plenty of voltage and fuel. 

I did try and balance the radiators and it all ran for two weeks fine. My pressure is 1bar. There is and expansion vessel as its a pressurised system.  I had to drill out a broken shader valve on this and added a valve extention which has held. 

I cant find any webasto engineers local.  I think the issue is the system balancing,  possibly air? 

Any advice  ideas welcome. 

I should add, the system crashes, doesn't shut down normally unless I shut it down myself. 

[Mike Adams]

Sounds like the unit is overheating and shutting down. The use of thermostatic valves can cause problems if you have them. The circulation pump may be not up to it. Does it start up once it has cooled down? Does the pump run on for a while when the burner switches off? Check the flow and return temperatures. If the return temperature is too high it won't like it. The design needs to ensure that air cannot collect in the heat exchanger or pump and that air can be released from a high point near the boiler.

[Phil Hill]

Hi Mike thaks for your reply.

Yeah no thermostatic valves only locking valves. It's a pressurised system. I played with the valves 2 weeks ago and things worked well until now? The system was doing the same then. 

The expansion vessel releases water when I depress the valve. Should this happen? Have I damged an internal bladder drilling out the old valve? 

I took the out pipe away from the webastow quicky to release any air. And have bled all the radiators. At cold the system is at 1 bar. 

Should I just replace the expansion vessel. Drain the system and then refill? I can't find a Webastow expert any where local to me. Or any who don't have any openings for 5 weeks ! 

 

Many thanks

Phil. 

 

[Phil Hill]

I definitely think the issue is the expansion vessel.  I'll get a new one as the membrane has failed. There shouldn't be water coming from the valve. 

[Tam & Di]

20 hours ago, Phil Hill said:

Hello all. 

So I've got a Webastow evo top, installed on a Collingwood widebeam. Boat and Webastow are 3 years old. 

I've had constant issues with the heater. In the 3 years I've replaced the burner, temp sensors and the heat exchanger.

 

Who fitted the Webasto? From what you say you should have been back to them about the problems. I suspect they'd deny all responsibility now though, because of the age and because you've tinkered with it yourself. You could always try though.

 

Tam

[pete.i]

Not an expert on webasto but there definetly shouldn't be water coming out of the valve on the expansion vessel.

[Mike Adams]

13 hours ago, Phil Hill said:

Hi Mike thaks for your reply.

Yeah no thermostatic valves only locking valves. It's a pressurised system. I played with the valves 2 weeks ago and things worked well until now? The system was doing the same then. 

The expansion vessel releases water when I depress the valve. Should this happen? Have I damged an internal bladder drilling out the old valve? 

I took the out pipe away from the webastow quicky to release any air. And have bled all the radiators. At cold the system is at 1 bar. 

Should I just replace the expansion vessel. Drain the system and then refill? I can't find a Webastow expert any where local to me. Or any who don't have any openings for 5 weeks ! 

 

Many thanks

Phil. 

 

Hi

There should not be water coming out of the air side of the water expansion vessel it means the bladder has failed only option is to replace. Try to get  a decent one as some are poor quality.

You should have a bleed valve at the highest point in the system but maybe you can use the radiators. How do you get antifreeze into the system?

 

[Chris John]

2 hours ago, Tam & Di said:

 

Who fitted the Webasto? From what you say you should have been back to them about the problems. I suspect they'd deny all responsibility now though, because of the age and because you've tinkered with it yourself. You could always try though.

 

Tam

It’s a Collingwood build. Waste of time getting them to fix anything. 

[Tam & Di]

Webastos are generally very reliable, and it does sound more like a system design problem of some kind.

 

Tam

[Phil Hill]

Top of towel rail or take off out let pipe and fill through that. I've got a new 8l expansion vessel. System is put in correctly and works well when working. Webastow itself has had new burner, heat exchanger and temp sensors. It works but system balance is off due to expansion vessel fault. 

 

Hopefully will sort now. Will update. 

Lack of webastow engineers around. My area. 

 

Cheers

Phil. 

[Phil Hill]

So I've changed the expansion tank. But still no joy. System shuts off after start up. Pump works, fuel is going in. Pressure is 1 bar. God knows what else to do. Except take off the unit and check. But it should be pretty clean as burner was decoked in spring. 

Anyone know of a good engineer in the Pe ton Hook Mariner area kt168py please put details on a comment. Many thanks, I can't find anyone. 

The ones on the webastow site are not in business anymore?? 

[Mike Adams]

Ok. In itself changing the expansion tank will not directly effect what you are saying. When you say it shuts off after start up do you mean the boiler gets hot before switching itself off. How long does it take  before it turns off. They normally make two attempts to start before they shut down due to a fault. How hot is the boiler when it switches off, it should be still cold if water is circulating properly. When you switch on can you hear it

1. purge with the fan

2. hear the dosing pump ticking slowley

3. hear the dosing pump ticking faster as it turns the igniter on

4. motor fan speeds up and off you go

If that is the case after what period does it shut down? It only takes a few minutes if there is no water in it or circulating for it to operate the safety cut out.

I guess it is a fairly new unit - they normally have a way of providing the fault codes either by a flashing light or something.

[Phil Hill]

It's a 2019 with no obvious fault code lights. 

It does the cycle of starting up and the water begins to warm up. Then a few minutes later it just shuts of. There is the ocassional smell of diesel after this? I wondered if the exhaust is clogged ? Or could this be a glow plug issue? I think I'll have to send it off. I'm getting tired off the constant problems I've had each year with it. And more annoyed that there is noone around who deals with them in my area. 😂

I had a heat exchanger issue where it had cracked. I changed this. The previous webastow engineer didn't tight the unit up properly as one of the screws I found loose. 

It worked OK for two weeks after similar symptoms.  I pumped some air into the expansion vessel then and it worked. So hence why I wondered if the expansion vessel was the issue. 

 

Looks like I'll be taking it out and sending off. Any recommendations? 

[Phil Hill]

Mike Adams 

Your local. Is there a chance I could pay for your services if you deal with webastows? 

 

07799621217

Or edithead1@gmail.com.  

 

 

[Phil Hill]

I've taken it off.  I think the burner was damged from the cracked heat exchanger. The lip at the end has corroded away! 

I thought it was superficial . It was a new burner!

I'd forgotten about the lip as it did run ok for awhile after the exchanger was changed. 

Fun times.  

Oh well. 

Edited October 3, 2022 by Phil Hill
Poor grammar by me

[Mike Adams]

It could be a crack in the heat exchanger, as the water heats up the unit expands, water gets into the burner and extinguishes the flame. That might account for the unburnt diesel smell. You seem to have spent a lot of money on it for such a new unit and the reason for failure is probably down to the installation. I don't know what model you have but probably a 'Thermotop'. I suggest you contact someone like Butler Technic and send the unit to them. I only have experience of fitting them on my boats but being a cheapskate I just buy old car ones from crashed cars, and modify them to suit.

[Phil Hill]

I've only just replaced the heat exchanger. When that failed I got alot of smoke. This time nothing. 

I've taken burner out and it appears that there is unburnt fuel. Possibly glow pin? 

I'm going to get a new burner. And hope! 

I've not been  blessed with a reliable webastow !  Every year another issue. 

I've only just replaced the heat exchanger. When that failed I got alot of smoke. This time nothing. 

I've taken burner out and it appears that there is unburnt fuel. Possibly glow pin? 

I'm going to get a new burner. And hope! 

I've not been  blessed with a reliable webastow !  Every year another issue.

[Phil Hill]

The residue if the unburt fuel is in the metal area of the fan housing above the burner. The exchanger is dry. Where before it was soaking. The installation was fine. Its to the book by Collingwood. I had work done on warrantyby a webastow engineer but the guy seemed to not tighten down as a year later I found one of the bolts loose! Which may why the exchanger failed originally.  Who knows.