Kelbs

Hello Detling, The flow pipe leaving the Webasto falls from the unit to pass through the bulkhead then falls again once through the bulkhead to get to floor level where it tees off to go to the first rad (also on the bulkhead) and goes and feeds all the other rads. Before going off to feed the rads, about 40cm after that first tee on the floor level I have put in a tee which comes off to feed the Calorifier with 15mm pipe, this tee is a reducer from 22 to 15mm. It certainly is getting very very hot and is probably close to, if not boiling. Would this then create bubbles in the system? And do you know why this would cause clunking in the pipe? I've been assuming that this was the trapped air. Its a vertical calorifier but I still don't know how to bleed it. I have a gate valve on the return coming out of the calorifier and if I open it fully it drips. I've done this a few times and not noticed any air coming out. Sorry Tony, I've not had the time to draw out a diagram yet. There are no angles greater than 45 degrees. It seems like the water is able to pass around at least part of the system as I can hear water moving around the radiator half way up the boat. Thanks all, I very much appreciate the help and advice

Each of the Rads has a bleeding valve at the top, the header tank which is at the highest point in the system has an open vent which I believe is an auto bleed. The only section which I can't bleed is the calorifier which the hot water from the webasto coils up in. I could try to draw the system out on paper if anyone thinks it would help but it would be difficult to show all the height differences.

Nope, still a bit of a mystery. I've been away over the weekend so haven't had much chance to play around. When I got back yesterday I removed the cold water return from the unit and let the water from the hot flow pipe run back through the unit. I then spent a good hour bleeding all the Rads while trying to run the Webasto. I managed to get a bit of air out of the highest rad but still no joy getting the unit to run fully. If I remove the 5amp fuse and put it back in then the water pump turns on and I can hear water flowing through the Rads. Once the start up sequence gets well underway, the flow pipe gets very hot, almost to hot to touch, and that heat does make it's way into the boat but the unit cuts out before anything exciting happens. Just before the unit cuts out the flow pipe makes a few clunking noises and jolts about a bit. Which I am assuming is trapped air. Tonight, if it's not raining, I will try disconnecting the flow pipe and turning the pump on to see if it will pump the water out of the unit. I think there must be a clump of air in the system which needs bleeding out but I can't seem to find it. Any ideas? Beau

Thanks for that Rob. I finished work late today and am knackered so didn't give bleeding the unit a go, however I gave it a token start up while it was going through the start up and I could hear the water pump going I gave the hot water flow pipe a wiggle around, in between the Webasto and the bulkhead, trying to move anything along. There were several big clunks which happened. I'm not really sure how best to describe it but the pipe moved when the clunk happened and it sounded like something was having trouble passing through the pipe. Is this possibly air inside the Webasto trying to get out/restricting the water flow? It felt as though it was on the flow pipe (hot water leaving the unit). Beau

Tony, I appreciate that you've taken an interest in this post and are trying to help however you are being patronising and unnecessarily rude. There is no need for it. Yes the Webasto circuit is separate to the engine coolant system, I have used the black flexiable engine hose to run from the webasto unit to the bulkhead where they join onto the 22mm speedfit pipe. I'm not ready to drain over 50L of fluid from the system just yet. I would prefer to eliminate the other possibilities first and save the worst until all other options have been eliminated. Hence following advice from others first. Especially when the advice is from people who have experienced what seems to be the same issue.

Cool. I'll start by loosening the jubelie clip then wriggle the pipe. If nothing happens then I'll take it off. Update tomorrow

Thanks Chewie, will give it a go when the sun comes back. I think I will try that but without the clamps, as if bleeding a rad. Feeling optimistic.

Thanks Chewbacka, very helpful. Have you any idea how I would be able to remove the bastarding bubble from the system without creating more airlocks?

There is only one TRV on one rad. The other three rads have standard valves and all of the radiators are teed off the flow and return pipes. I was considering clamping the pipes shut but can't picture a situation where air wouldn't find its way into the unit again. The header tank is about 30cm from the ceiling in the boat and I would have thought this would have bleed any air out naturally. If I bleed all water from the webasto, while the flow and return pipes are clamped shut, then reconnect the pipes but don't turn the unit on, will any air caught in between the pipes (where they were clamped) and the Webasto make its way naturally to the header tank? Is there a way to bleed the circulation pump? Possibly by releasing the screws on it?

This is exactly what's happening, water in the first 50cm of pipe is heating then nothing. So it's sounding like there is an airlock at the circulation pump. If I remove the pipes connecting to the webasto a large portion of my water will drain. In heinsite I should have put isolators on the pipes just before they exit the boat into the engine bay. Has anyone got a helpful tip of how to plug the black flexiable engine hose pipe while I unblock the Webasto? Cheers

This is all pointing towards an airlock situation. Before anyone tells me off any more, no I haven't checked the glow plug yet. The webasto candour has suggested that I check the circulation pump is working by taking the screws out the bottom and manually turning it. The webasto header tank is self bleeding I believe and I have bled all the Rads prior to starting. How do I get airlock out of the Webasto unit itself? Could it possibly be short cycling?

Also, the unit gets very very hot and starts to warm the water pipes. I may be wrong but if smoke is coming out of the exhaust and the unit is heating up would that not mean the glow plug works? Is the glow plug only used in start up or is it on the whole time the unit is on?

Again, I don't know where the glow plug is. Perhaps if someone could tell me then I could check. I'm not just ignoring the matter but I think I'd have to crack open the casing to find the glow plug.

That's who I got mine from.

Cheers Tony. Will try this tomorrow.

Checked batteries when I got back from work and they were 13.3v, same at the Webasto fuse board. I tried to start it up another 4/5 times with no joy. I have tried restarting the unit by disconnecting the main heater wires, as recommended, and checked the exhaust pipe for excess fuel. Still the unit will not start up. One thought I have had is that the very first rad on the system has a TRV attached, I used it because it came free with the rad and it is out of sight. I know you aren't supposed to use TRV's with the Webasto system but I assumed it would be fine if left open. Does anyone have any experience with this? I contacted the seller earlier to ask for his opinion and he had this to say (amongst other things): 'Webasto claims that boats should have units that are capable working at lower voltages. Automotive units will work with batteries drained to 10.04v, 'marine' one can go down to 9.76v. Is it really the issue? All power inverters cut out at 10.5v to protect batteries, so would you want to drain your batteries to 9.76? That would make webasto work extra 5minutes before it cuts out and would cause permanent damage to batteries. Batteries aren't supposed to go below 11v or it will permanently damage them and reduce capacity. Other thing is most boats are on hookup all year round and voltage never drops below 13.2v." Any one know what I should try now?

It wasn't an eBay bargin it was sold by a reputable Webasto refurbishment company. Although it was cheaper than a new unit it still cost a decent chunk of money. The wiring loom was built to Webasto spec so should all be fine. I have 660 amps of battery bank and over 1000w of solar charging these. I know this is sufficient and can see on the victron app on my phone what the voltage of the battery bank is, as well as putting the volt meter on the bank itself. I will try again after work today once the batteries have had a full day of sun and should be up around 14v. There was a LOT of smoke on the first attempt then by the third and final for last night there wasn't any really. Will update later.

How do I access the glow plug? Do I take the top plastic case off? I contacted the company I bought the refurb unit from and they said it is most likely going to be the automotive version but that most of their clients fit the units in boats and they have never had an issue. I did check before I bought and they said it would be fine in a boat. They have since said they will take the item back if I decide I don't want it. Ideally I would use this one if possible as it's already plumbed in. Is it possible to use the automotive version?

Thanks Tony. I've managed to get fuel to the webasto, the issue was that I was screwed into the return pipe where there was no internal pipe. The other threaded weld joint, installed by the boat builder, does indeed have the internal pipe. Why would the Builder bother to weld threaded joints into the diesel tank and not fit the internal tube? In terms of the voltage, so sorry to everyone I offended by not replying sooner, I don't know where the glow plug is so didn't test on the unit. I did test at the fuse point and it was around 13v, I forget exactly what it was but it was plenty I am sure, please correct me if I am wrong. I wouldn't have thought the fuel pump would have been engaging, or the unit completing cycle after cycle if it was a voltage problem. Not just my opinion but going from a collection of comments across a range of groups. Now, after getting the diesel into the Webasto it still won't engage fully. I gave it three attempts since bringing the fuel through and still nada. It smoked a lot the first couple of times and the pipes and unit heated up but after it's cycle finished it still hadn't engaged. I feel confident that tomorrow will be filled with success, but any advice on how to get the unit started would be great. Should I be able to turn it on first time from the programmable timer or do I need to keep removing the fuse to reset the CPU? And how long should the unit take to spring into ignition. Cheers.

Thanks all very much for the advice. The problem is definitely that no fuel is coming through the line. There is plenty of voltage reaching the unit, I tested it earlier. I have disconnected the fuel line from the webasto unit and put an extra 20L of diesel in the tank, ran the unit 4 times and nothing came out of the fuel pipe. So I think the issue is deffenitly a lack of diesel to the unit. Trying to work out why is my next issue. I've attached a couple of pictures of the outlet from the diesel tank and the fuel pump. Not sure if anyone can help from these but anything is worth a go at the moment. The webasto is to the right of the pump and the tank to the left. The holes in the diesel tank were from the boat builders and I've assumed there will be piping inside to feed from the diesel tank. Thanks all, Beau

I do have an instruction manual and it does talk you through the commissioning procedure, very vaguely. Are you able to give any more advice on what this means. It looks to me to be to do with bleeding any air out of the rads and making sure the heating system is ready to go before turning on?

I think the header tank has a self bleeding valve on it, there is an open nipple next to the filling spout which I have been assuming that it is to let out any air. Will try bleeding the rads tomorrow regardless.

I'm not sure where the glow plug is, I'm assuming it's inside the unit? Nor am I sure where the filter is. Is there a filter built in to the unit as I haven't fitted one myself.

Hello lovely boaters, I've been fitting a Webasto Top C unit on my boat and today was the day it was supposed to all come together and work. As I expected it did not happen. After connecting up to the battery bank the unit would make some noise, as if it was sucking air through, I could feel the air coming out of the exhaust, no fumes. Then these diesel pump would start making a clicking noise, which got faster and faster, the unit speeds up and sounds like it's about to kick in and then it just doesn't. I did this 4/5 times hoping that it just needed a few attempts to get the diesel into the unit. Still no joy. Am I missing something obvious? It's a reconditioned unit and came with all the parts needed, anything missing I bought with Spencers recommendation. I'm hoping that I'm just being a Muppet and that I'm forgetting something simple. Please help :) going to post in a few places to gather the greatest amount of boater knowledge. If no one can help then I will look for a webasto engeneer to come and help out. Thank you all x

Hello all, Does anyone know of a way I can plumb into the Webasto twin port header tank without using flexible pipe? Ideally I would plumb the 22mm push fit straight into the unit. Thanks, Beau