Struggling to get the Webasto Top C to start up.

[MtB]

Just now, Kelbs said:

Brilliant, thanks Mike. I'll pick the bits up on my way back from work.

 

That might well be enough to get it going. Once the pump finds a circuit to pump around, the Eber will prolly work properly and push other air out into the rads where it can be bled out. 

 

 

[Chewbacka]

21 minutes ago, Mike the Boilerman said:

 

I wasn't going to mention that until the Eber is working!!

 

 

I was going to wait as well, but i know by then I will have forgotten.......

[Kelbs]

26 minutes ago, Mike the Boilerman said:

 

That might well be enough to get it going. Once the pump finds a circuit to pump around, the Eber will prolly work properly and push other air out into the rads where it can be bled out. 

 

 

What do I need to do once I've fitted the bleed valve? And why would the air go back to that point? Do we think there is air in the coil which keeps being pulled through to the heater? 

[MtB]

Just now, Kelbs said:

What do I need to do once I've fitted the bleed valve? 

 

Re-fill the system with water and open the air vent. Air will come out at first, then water. Then try starting the heater. Lots of gurgling will prolly result in which case keep checking the new air vent for air. Fit a length of copper tube say 300mm long between the new tee and the new air vent so there is a reservoir to accumulate the air.

 

3 minutes ago, Kelbs said:

And why would the air go back to that point?

 

Air rises to the top of a closed loop of pipe and water falls to the bottom.

 

 

4 minutes ago, Kelbs said:

Do we think there is air in the coil which keeps being pulled through to the heater? 

 

Yes, this exactly. A water pump will pump water but not air. As soon as air from the calorifier loop arrives at the pump, water flow stops and the Eber overheats. This is what several of us here think at the moment.

 

 

 

 

 

[Chewbacka]

It might help if you gave us a general photo showing the heater, pump and inlet side pipes as it feels that the pipes might run downhill to the pump, so when the pump stops air rises back up the pipe away from the pump ready to come back down on the next start attempt.

[Kelbs]

3 minutes ago, Mike the Boilerman said:

Yes, this exactly. A water pump will pump water but not air. As soon as air from the calorifier loop arrives at the pump, water flow stops and the Eber overheats. This is what several of us here think at the moment.

 

 

 

 

 

So why would the air keep making its way back to the calorifier once the pump fails to get going, instead of staying up at the pump?

 

Do I need to drain the 55L of antifreeze from the system, then flush through with water, then top back up with the coolant?

 

 

Just now, Chewbacka said:

It might help if you gave us a general photo showing the heater, pump and inlet side pipes as it feels that the pipes might run downhill to the pump, so when the pump stops air rises back up the pipe away from the pump ready to come back down on the next start attempt.

Answered my question before I had typed it. Will send one over this evening. 

[Chewbacka]

Just now, Kelbs said:

So why would the air keep making its way back to the calorifier once the pump fails to get going, instead of staying up at the pump?

 

Do I need to drain the 55L of antifreeze from the system, then flush through with water, then top back up with the coolant?

 

 

See post 105 as we posted together 

[MtB]

3 minutes ago, Kelbs said:

Do I need to drain the 55L of antifreeze from the system, then flush through with water, then top back up with the coolant?

 

Puzzling. Why so much water? I'd have expected ten litres os so with a two or three rad system. Maybe less.

 

But no you don't need to fully drain. Arrange two bungs to block up the cold feed and vent connections at the header tank, then air will not be able to get into the system. This means water can also not get out as air cannot get in. Then you can swap the SpeedFit elbow for a tee with minimal water spillage.

 

Then remove the bungs again.

 

 

 

[Kelbs]

I worked out that the 22mm pipe work alone would hold something like 12L. 55 surprised me I was expecting 40ish. There are three double Rads, the calorifier (75l) coil, the header tank etc. Lots of areas for antifreeze to fill. The boat is 57x10 ft

 

Feeling optimistic about this new bleed valve. Is there any particular valve which would be best?

[MtB]

10 minutes ago, Kelbs said:

I worked out that the 22mm pipe work alone would hold something like 12L. 55 surprised me I was expecting 40ish. There are three double Rads, the calorifier (75l) coil, the header tank etc. Lots of areas for antifreeze to fill. The boat is 57x10 ft

 

Feeling optimistic about this new bleed valve. Is there any particular valve which would be best?

 

Any fitting that van be opened to let air out will do. Even a compression end cap. Best type would be an automatic air vent, and the best of the AAVs is the Flamco FlexVent  

https://www.ebay.co.uk/itm/Flamco-Flexvent-1-2-Automatic-Bottle-Air-Vent-Valve-10-bar-120-C-auto-Boiler/301219960771?epid=1788621058&hash=item46221bd7c3&_trkparms=ispr%3D1&enc=AQAEAAADMKvsXIZtBqdkfsZsMtzFbFsbX3WcW5fmB%2Fx7ZbaZTyexAey%2BPZPfdcp6s1t2bgLwpIefa1ir1kNrZ1wCspExhe8LN8bnuou5%2FfUDaAliarf1cOjD2QAn2wmQu2PpmqVPCDriwHnqkqKyxlQIa6UfaJFNc9NDZGGHAXTcBR%2B1EHBd4qNojaRmo6CeWQRxSnhc5yu7cYmjntun%2F17Nh6m7SUUeHqRbtKA6h7%2FW8HlDMaqTk6Sjg1sVTc2H2oPDo7vPzMUDSEzt0W%2FGMMbLHfWtaQNUiXk2FJox24q2ts1332i%2FmFJCGzh6GgJFiNmpbfHRyMa9O%2FUm90DuHQcpnGkBIwoIg2qy6d65etrHrHuPqXijCINIAB9TaMpnjL3ZKz54Fy4qapMSY8%2Bcsz%2FQa7DAi%2BJ2%2FaA1LU08TrwyycSUKrrf1nmCAeAyQjOumUxrsjuicyAm4O10TIdAb9etVz5tPMZxN1hmVR9Sg1h%2BW7%2F7hHOZ7Cg1PzckZJ3W7WIwrujc780XiAEb5XwoJA5RJwGiXqa27Uo5WMYN23hvXEFBV2WnomSX%2FD82WBkQFDVDaZjatIrOIzteKTqoY47LPvyqgpbKLSlm3kM5lI48aRUhlVGaoKz6dL%2FF%2FByap0YDYZzey1q%2FheRacXdEL3f5OrB0pZCTrAZuu%2FoTYpftfuMQHri23URjs4mEpi3xMNq%2FyNlKWnntPrTZKj4q76evjWHNLV6Co%2FwxGeM%2BNjx0rGPvtImlvhOFjIzWQFu2xW6Q6eYQN6LoEGlqym9Hq5vn3gvNLFTSzv0VkZ9gwbZuUHzUQJTBrJitfExxY5%2FNmq9A%2BP2Q4oT3E2wclTu5W0%2B9E0Xw9En6fPeyLEWPf%2FNbx8YgHgNZd0Kno46CocIVioP2CGJlh2jPv5wXx%2BtW%2B2gB4R4ZUy32W466uFj1Q3Hr9%2Fnz0UIdjkytmeih%2FOmIde7%2BQiRGrQbagKjc9lJzm%2FETiR5zBlKXXtbZEslVJV6gxlZXBUX1Cr3n0F0tDszItKpt%2FZvq21xSBvVXtNq%2BoiLZ%2FFH%2BGjHZf3SNXIaatDXvFVLXDlYoMYl93ygUKjG%2FJflnsutBFw%3D%3D&checksum=301219960771cf982cd8065646ea852e50e61a6f865b

 

 

 

Your whole system is a lot bigger than I was imagining....  on reflection my own little two rad system probably contains 20L...

 

 

 

 

[Tony Brooks]

I agree the calorifier part of the circuit will trap air but there is still a good chance it will also be trapped in or close to the boiler's pipes. This all depends upon how the pipework has been installed but if the horizontal pipes from and to the boiler have a downward section anywhar it is likely to trap air. If so you need more bleed points to release it.

[WotEver]

3 hours ago, Mike the Boilerman said:

Any fitting that van be opened to let air out will do. Even a compression end cap. Best type would be an automatic air vent...

How do they work Mike? A little float that opens if there’s air above the water?

[MtB]

4 minutes ago, WotEver said:

How do they work Mike? A little float that opens if there’s air above the water?

 

Yes, just like the petrol reservoir in an old fashioned carburettor. A float an a needle valve.

 

 

[WotEver]

21 minutes ago, Mike the Boilerman said:

Yes, just like the petrol reservoir in an old fashioned carburettor. A float an a needle valve.

Cheers

[Tony Brooks]

1 hour ago, Mike the Boilerman said:

 

Yes, just like the petrol reservoir in an old fashioned carburettor. A float an a needle valve.

 

 

In that case I would fit a manual one, had enough of leaking float needle valves

 

I think another version has fibre washers that swell and seal the valve when wet but dry out and shrink with air in the valve.

[WotEver]

1 hour ago, Tony Brooks said:

In that case I would fit a manual one, had enough of leaking float needle valves

The best way of knowing the fuel cock on my old BSA Bantams was on was to watch for the drip from the float chamber

[rusty69]

1 minute ago, WotEver said:

The best way of knowing the fuel cock on my old BSA Bantams was on was to watch for the drip from the float chamber

Sounds similar to my outboard motor. 

[David Mack]

20 hours ago, Kelbs said:

 

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....

And the return pipe to the Webasto? 

If both pipes fall from the Webasto then you are likely to get air (or steam) trapped in the heater itself. Your vent pipe should rise continuously from the heater so that air can escape. 

[Tony Brooks]

8 minutes ago, David Mack said:

And the return pipe to the Webasto? 

If both pipes fall from the Webasto then you are likely to get air (or steam) trapped in the heater itself. Your vent pipe should rise continuously from the heater so that air can escape. 

That would certainly do it but if too difficult to arrange then air bleed point(s) at the boiler outlets would do.

[Kelbs]

It's quite untidy down here but it's not my priority at the minute

[Detling]

 

Can you tell me how air gets out of the webasto unit? the pipes dip before they go through the bulkhead!  this was mentioned in very early posts.  You can try easing the joint of the flow pipe at the top of the webasto (with it off) and wait for water to seep out then re-tighten the joint. this process may need doing several times to get all the air out.  Better still put a T joint right by where the top flow pipe comes out, point the T upwards and put a valve on it, open valve to bleed close to operate. once the air is out the webasto should run, but until you have removed the air from the calorifier coil it won't give hot water and may short cycle due to smaller load.

 

 

 

"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. "

 

When my house immersion heater thermostat failed the hot water tank reaching boiling point was like thunder a few yards away, so yes loud bangs and thumps. Steam is very powerful look at what the Victorians did with it.

 

[Tony Brooks]

That photo suggests to me that there are tow air traps per hose. One in the boiler and a the boiler end of the hose and one in the other end of those hoses to the right where the hoses fit onto the bulkhead fittings.

 

Having enhanced the photo it looks as if there may be an air bleed hose or an air bleed of some sort on one the boiler connection where the hose connects in a vertical direction. If the small diameter black "hose" that seems to come from there is a vent then the boiler might self vent but I am not sure what you have. It will not vet any air trapped by the bulkhead fittings.

[Kelbs]

16 minutes ago, Detling said:

 

Can you tell me how air gets out of the webasto unit? the pipes dip before they go through the bulkhead!  this was mentioned in very early posts.  You can try easing the joint of the flow pipe at the top of the webasto (with it off) and wait for water to seep out then re-tighten the joint. this process may need doing several times to get all the air out.  

The water has circulated a number of times but doesn't get very far, as previously mentioned. Surely the air trap isn't in the black pipe leaving the Webasto at the top. This is the flow. Would the air not be pulled to the pump and then start causing a problem with the unit over heating.

 

It was mentioned earlier that the air bubble could work it's way back to the calorifier after the unit turns off. Hence why I've now installed a bleed point next to the gate valve on the return pipe leaving the calorifier..

[Tony Brooks]

10 minutes ago, Kelbs said:

The water has circulated a number of times but doesn't get very far, as previously mentioned. Surely the air trap isn't in the black pipe leaving the Webasto at the top. This is the flow. Would the air not be pulled to the pump and then start causing a problem with the unit over heating.

 

It was mentioned earlier that the air bubble could work it's way back to the calorifier after the unit turns off. Hence why I've now installed a bleed point next to the gate valve on the return pipe leaving the calorifier..

Typically when circulation is prevented on that sort of boiler it will fire up and the shut down with the pipes close to the boiler and the boiler body very hot. As far as I can understand from the 123 posts so far this is exactly what is happening. The rest of the system will not get hot.

 

If you have any high spots in pipe runs such as the calorifier or the black hoses air can get trapped in them and prevent water circulation. The height is relative to the pipework around it NOT relative to the header tank or heater. The air vent pipe, if there is one, should run from the highest point in the system in which air might get trapped so in this case probably the boiler but there seems to be others so those need air vents so you can bleed air out the all the high spots.

 

Yes, air will get trapped in the boiler the way you have plumbed it because both hoses drop down away from the boiler and as already explained water pumps like the one in the Webasto can not and will not pump air, the impeller just spins in the air bubble. That sort of pump needs a system that is either designed to self bleed (yours is clearly not) or sufficient bleed points to vent all the air trapped in the system.

 

Although you could try loosening the the hoses on the bulkhead fittings and partially removing them (one at a time) to vent any air from there and the do the same at the boiler end (do it return pipe first, then the hot outlet)it would be far easier for the future to fit bleed points. Do it supply pipe at the bulkhead fitting - supply pipe at the boiler - outlet pipe at the boiler - outlet pipe at the bulkhead fitting.

 

It would be far better to reconsider the use of such long hoses and the pipe runs to eliminate as many high spots as possible before fitting bleed valves.

 

Remember that it is best to consider that any air trapped in pipework will NOT be forced to move downwards and will be very likely to stop circulation. Air can only move upwards.

[chevron]

I would move the webasto unitlow as possible so the rubber pipes are not going uphill to the unit exhaust if on a flexible pipe,fuel line will bend easily five minutes job and try running it again should help with air locks?