Back boiler Failure

[rusty69]

34 minutes ago, DShK said:

I just noticed that it's only the top of both radiators that's hot - not the bottom. This would explain why the bottom pipe isn't warm, the warm water isn't making it to the bottom pipe. Not sure what this is indictative of though. Obviously hot water rises, perhaps in this is because the radiators haven't been saturated yet and the heat is all released at the top. But I would expect the bottom to be at least a little warm?

Maybe sludge as someone else suggested up thread.

[BEngo]

David was talking about the situation where the back boiler has heated to  boiling.   Steam then vents into the header tank and the bottom pipe feeds cooler water into the bottom of the boiler.

 

N

[DShK]

1 hour ago, Jon57 said:

There’s a Laing d5 12volt pump just the same as the pump above  half the price.

 

Hmm interesting, that's a PC watercooling pump. I'm not sure if it is big enough to cope, and seems to be out of stock everwherem but certainly an idea to look into, thanks!

1 hour ago, Higgs said:

 

 

If both radiators are reacting the same, you could still rule out radiator problems. The flow on the return seems to be weak or non existent. 

 

 

This seems to be one of the problems I need to solve. My return pipe is fairly flat but definitely has a decent rise to the  boiler for the last two metres. I would think that part of the return flow would be due to a fall towards the boiler. One thing I don't understand is how the header tank being piped off at 5 wouldn't negate the upward pressure of the rising hot water? The elbow leading to the calorifier does have a very slight rise, but it is a bed which AFAIK thermosyphon systems don't like. The upward pressure and rising hot water surely just rise to the header tank, not helping the flow into the calorifier? Perhaps I fundamentally don't understand the mechanics at play here.

 

41 minutes ago, magnetman said:

When I did a Rayburn in my narrow boat I led the flow pipe vertically straight out the top of the boat then ran it from a tee to the back of the boat along the deckhead lining. Header tank was plumbed to the return which was on the floor. Header tank recessed into the lining so that it was high enough and this was also vented to outside of boat. 

 

If the thing ever boiled over all of the steam and hot water was outside not inside. Seemed a better approach to me. 

 

Primary circuit was 28mm, no pump and I ran radiators and calorifier on 15mm pipes from flow and return pipes. Worked brilliantly. Best heating setup I've ever had but Jesus H Christ on a Jesus H bike did it go through the solid fuels ! You would need a small forest !

 

It was Alan at Uxbridge Boat Centre who told me to take the flow vertical to get the thermosyphon working as well as possible. Boat was slightly now up so the vent at the end of the flow pipe was the highest point and an open vent. 

 

When you say your return pipe was on the floor, did it fall back to the boiler, or was it literally on the floor? Your vertical pipe setup is the same as mine, other than the Tee. I suppose this helps with the issue of the trim of the boat too. Interestingly when I look up domestic thermosyhpon systems, they often have a rise right before the hot water tank, rather than at the boiler. 

 

When I did get hot water, the bottom pipe did get warm, at the very least near the calorifier.

 

 

 

edit: note this is the old rad setup, just posting so it's easier to find again

Edited January 16, 2023 by DShK

[magnetman]

The flow pipe was against the deckhead (ceiling) lining it went straight back to the engine room then directly to floor level where it returned all the way back to the stove and went back up to the lower boiler fitting. I did it all myself in 28mm fittings bought from a local scrapyard. 

 

I was surprised how well it worked and was even able to add a small radiator about 15ft forward of the burner in 15mm pipe and it got hot. 

 

The temperature difference between flow and return is the key to getting rads to work. 

 

Of course the Rayburn (MF model) did have a large L shaped boiler which helped. That was a warm and dry 55ft narrow boat and the engine (Russell Newbery) was a lot easier to start after installation of the radiator beside it. 

Edited January 16, 2023 by magnetman

[ditchcrawler]

1 hour ago, DShK said:

 

 

If I have to fit a pump, this looks like my best option? All the others I've found look like they are for specific systems and won't fit inline nicely. It's so expensive though, does anyone know of one a bit more palatable on the wallet? https://www.jabscoshop.com/marine/pumps/circulation-pumps/59520-0000-8-12-volt-dc-ecocirc-pump-non-self-priming-for-hot-water-circulation.htm

I find mine quite noisy 

[Jon57]

Just now, ditchcrawler said:

I find mine quite noisy 

Mine isn’t 🤣

Just now, Jon57 said:

Mine isn’t 🤣

Even on number 5 speed.

1 minute ago, Jon57 said:

Mine isn’t 🤣

Even on number 5 speed.

Might try it with my hearing aids in next times 🤣

[DShK]

2 minutes ago, magnetman said:

The flow pipe was against the deckhead (ceiling) lining it went straight back to the engine room then directly to floor level where it returned all the way back to the stove and went back up to the lower boiler fitting. I did it all myself in 28mm fittings bought from a local scrapyard. 

 

I was surprised how well it worked and was even able to add a small radiator about 15ft forward of the burner in 15mm pipe and it got hot. 

 

The temperature difference between flow and return is the key to getting rads to work. 

 

Of course the Rayburn (MF model) did have a large L shaped boiler which helped. That was a warm and dry 55ft narrow boat and the engine (Russell Newbery) was a lot easier to start after installation of the radiator beside it. 

Ah wow you had quite a rise on the vertical pipe then!

[Jon57]

Just now, DShK said:

Ah wow you had quite a rise on the vertical pipe then!

Naughty 🤣

[magnetman]

Yup straight out the top of the boat. You have to be careful about header tank which is why it was recessed into the lining and manually filled from outside. I didn't use any antifreeze in that as was on the boat 247 never let the fire go out anyway.

 

 

 

Open vent on flow and open vent on return which the header tank was plumbed into. Any trouble you get the agro happening outside. I did get steam fountains a couple of times which was quite amusing to watch on a cold day but not dangerous. 

[DShK]

While my boiler does glub glub glub, I'm not sure I have had instances of steam. There's been a couple of times where it made noise like it might have done, but generally it's just noise in the boiler.

 

One thought - surely the radiator needs to be sloped to make sure the cold water is falling through the outlet?

[magnetman]

1 minute ago, DShK said:

While my boiler does glub glub glub, I'm not sure I have had instances of steam. There's been a couple of times where it made noise like it might have done, but generally it's just noise in the boiler.

 

One thought - surely the radiator needs to be sloped to make sure the cold water is falling through the outlet?

There are no sloped areas needed. All you want is hot water to go up and as it cools it is obviously better, due to gravity, that it then goes back down. 

 

Once you have a temperature differential between two pipes you can attach radiators or calorifier to them and the water has to equalise itself. It's part of the laws of physics apparently. 

 

Have you bled the radiators of air? This is very important. 

[BEngo]

50 minutes ago, DShK said:

I just noticed that it's only the top of both radiators that's hot - not the bottom. This would explain why the bottom pipe isn't warm, the warm water isn't making it to the bottom pipe. Not sure what this is indictative of though. Obviously hot water rises, perhaps in this is because the radiators haven't been saturated yet and the heat is all released at the top. But I would expect the bottom to be at least a little warm?

The radiators will not get hot all over without really good circulation.  They are meant to cool the water down after all.  You also don't want the bottom pipe very warm as that reduces the temperature difference across the boiler, and hence the thermosyphon effect.

Ideally, the top half of the radiator will be hot, gradually fading to lukewarm or less at the exit.

 

N

[DShK]

A thought - tonight is cold, and will get colder. The boat is actually much toastier than I could safely run the stove before the radiator change. I think they are effectively pulling heat from the system. In the previous configuration, if the coil was blocked, there would be nothing at all to sink the heat beyond the pipe itself. I am HOPING that the fact that the rads are hot and the stove can run hotter is proof that the system works, the coil (remembering that I have had hot water in the past) is blocked. And once that is unblocked the problem will be solved. Nothing new said but I am just feeling optimistic

 

I have ordered some bits from screwfix (draincocks and adapters) to attach a hose and will be blasting it out tomorrow. Fingers crossed!

[magnetman]

7 minutes ago, DShK said:

A thought - tonight is cold, and will get colder. The boat is actually much toastier than I could safely run the stove before the radiator change. 

 

That's good the boat is warm. Long may it remain so. It seems to be a little on the cool side outdoors tonight. 

 

Good luck with the calorifier. 

[rusty69]

Any progress on this?

[DShK]

I haven't flushed the calorifier. I recently found out I'm going to be made redundant so I've been focusing on hunting for a new job. However, the system does seem to be behaving ok - the bottom pipe gets warm and now so does my hot water (The key word being warm) and I can still boil the water in the stove (it does seem to be effected by the trim of the boat). But I can get the boat warm and the radiators are working amazingly 

 

So it's behaving acceptably, if not perfectly  I'll probably leave trying to flush the calorifier until it's a bit warmer.

 

So much thanks to everyone who was so generous with their time and advice. I definitely learnt a lot too, always good to gain new life skills! 

 

I'll update properly when I give it a flush

 

Edited January 29, 2023 by DShK

[rusty69]

8 minutes ago, DShK said:

 

I'll update properly when I give it a flush

Thanks for the update. Good luck with the job hunting.

[DShK]

Update: new job found so that panic is over. Worked out nicely, amazing career move.

 

I have filled my diesel tank since and the stove went back to it's old self - very very easy to boil. So the trim of the boat DOES make a difference, it's not just about the inititial vertical rise. I will fit a pump and be done with it. Using a PC watercooling pump was mentioned in this thread. I did some digging and I am 95% sure this pump is the same as the £350 Jabsco one from midland chandlers. At £150 it's quite the saving. The price difference is madness.

https://www.aquatuning.co.uk/water-cooling/pumps/d5-series/d5-pumps/1253/laing-d5-pump-12v-d5-vario-1/2-ig?sPartner=googleshoppinguk&gclid=CjwKCAiA9NGfBhBvEiwAq5vSy9hs7NkQHsdEyQKQ7zApCEeKh4x0zA_6B2B9UwJP0xbSc7uPjA-v-BoCiQYQAvD_BwE

 

[Jon57]

1 minute ago, DShK said:

Update: new job found so that panic is over. Worked out nicely, amazing career move.

 

I have filled my diesel tank since and the stove went back to it's old self - very very easy to boil. So the trim of the boat DOES make a difference, it's not just about the inititial vertical rise. I will fit a pump and be done with it. Using a PC watercooling pump was mentioned in this thread. I did some digging and I am 95% sure this pump is the same as the £350 Jabsco one from midland chandlers. At £150 it's quite the saving. The price difference is madness.

https://www.aquatuning.co.uk/water-cooling/pumps/d5-series/d5-pumps/1253/laing-d5-pump-12v-d5-vario-1/2-ig?sPartner=googleshoppinguk&gclid=CjwKCAiA9NGfBhBvEiwAq5vSy9hs7NkQHsdEyQKQ7zApCEeKh4x0zA_6B2B9UwJP0xbSc7uPjA-v-BoCiQYQAvD_BwE

 

That’s a good solution. 👍 

[DShK]

An update! It took a little while to get the pump sorted, had some weird stuff happen with my fitting deliveries... long story, sorted now.

 

I installed the pump on the return feed, close to the calorifier. Horizontally.

 

Pump does it's job! Which is fantastic, I can run the stove at a high temp now. HOWEVER, while the pump itself is whisper quiet, it's resulted in a lot of wooshing and trickling sounds coming from the pipework. Really quite loud. Found it hard to sleep with it on. I was working on the theory that there is an airlock in the place that I had previously suspected. Tried to clear this without "surgery". Rocked the boat about etc (reluctant to do the hosepipe method as not sure the pump would like this). Eventually it did quieten down to a whisper! However, the noise returned. I am reluctant to just cut open the pipe to attempt to bleed it on a whim... because if this IS the issue, then it returned very quickly... so need to figure out the underlying cause.

 

What I hear is a lot of noise, wooshing/bubbling which sounds like its coming from perhaps the pump. Then this passes and I hear a trickling sound coming down the vertical pipe leading to the calorifier. Which really does suggest to me that there is an airbubble there? 

 

Is the way forward to try and find a way to make it so there isn't likely to be ever (unless the boat is seriously rocking) a high point there? It might be quite a difficult job as I would have to find a way to cut some extremely inaccessible pipe, as I can't rotate the pipe that the elbow connects to.

[PaulJ]

Ive found , in the past, its better to fit the pump close to the backboiler and control it by pipe stat fitted as close to the backboiler output pipe as possible and not at the usually easier and more convenient other end thats near the electrics. Assuming your calorifier is the other end of course.

Reason for this was that although it was circulating well through the rads you could still get kettling in the back boiler if ran hard. 

 

[ditchcrawler]

48 minutes ago, DShK said:

An update! It took a little while to get the pump sorted, had some weird stuff happen with my fitting deliveries... long story, sorted now.

 

I installed the pump on the return feed, close to the calorifier. Horizontally.

 

Pump does it's job! Which is fantastic, I can run the stove at a high temp now. HOWEVER, while the pump itself is whisper quiet, it's resulted in a lot of wooshing and trickling sounds coming from the pipework. Really quite loud. Found it hard to sleep with it on. I was working on the theory that there is an airlock in the place that I had previously suspected. Tried to clear this without "surgery". Rocked the boat about etc (reluctant to do the hosepipe method as not sure the pump would like this). Eventually it did quieten down to a whisper! However, the noise returned. I am reluctant to just cut open the pipe to attempt to bleed it on a whim... because if this IS the issue, then it returned very quickly... so need to figure out the underlying cause.

 

What I hear is a lot of noise, wooshing/bubbling which sounds like its coming from perhaps the pump. Then this passes and I hear a trickling sound coming down the vertical pipe leading to the calorifier. Which really does suggest to me that there is an airbubble there? 

 

Is the way forward to try and find a way to make it so there isn't likely to be ever (unless the boat is seriously rocking) a high point there? It might be quite a difficult job as I would have to find a way to cut some extremely inaccessible pipe, as I can't rotate the pipe that the elbow connects to.

You are not drawing air in through the header tank and vent by any chance?

[Jon57]

57 minutes ago, DShK said:

An update! It took a little while to get the pump sorted, had some weird stuff happen with my fitting deliveries... long story, sorted now.

 

I installed the pump on the return feed, close to the calorifier. Horizontally.

 

Pump does it's job! Which is fantastic, I can run the stove at a high temp now. HOWEVER, while the pump itself is whisper quiet, it's resulted in a lot of wooshing and trickling sounds coming from the pipework. Really quite loud. Found it hard to sleep with it on. I was working on the theory that there is an airlock in the place that I had previously suspected. Tried to clear this without "surgery". Rocked the boat about etc (reluctant to do the hosepipe method as not sure the pump would like this). Eventually it did quieten down to a whisper! However, the noise returned. I am reluctant to just cut open the pipe to attempt to bleed it on a whim... because if this IS the issue, then it returned very quickly... so need to figure out the underlying cause.

 

What I hear is a lot of noise, wooshing/bubbling which sounds like its coming from perhaps the pump. Then this passes and I hear a trickling sound coming down the vertical pipe leading to the calorifier. Which really does suggest to me that there is an airbubble there? 

 

Is the way forward to try and find a way to make it so there isn't likely to be ever (unless the boat is seriously rocking) a high point there? It might be quite a difficult job as I would have to find a way to cut some extremely inaccessible pipe, as I can't rotate the pipe that the elbow connects to.

Is the pump on constantly? If so have you turned the speed pump up to max. Sounds like the water might be getting too hot in the boiler. Can you check the flow and return temp at the boiler when the noise starts.

[DShK]

48 minutes ago, PaulJ said:

Ive found , in the past, its better to fit the pump close to the backboiler and control it by pipe stat fitted as close to the backboiler output pipe as possible and not at the usually easier and more convenient other end thats near the electrics. Assuming your calorifier is the other end of course.

Reason for this was that although it was circulating well through the rads you could still get kettling in the back boiler if ran hard. 

 

I'll bear this in mind thank you, I'll refit it in the future. I want a good break from plumbing ASAP tbh! (I also have a leak that I've been dealing with).

24 minutes ago, ditchcrawler said:

You are not drawing air in through the header tank and vent by any chance?

I don't THINK through the tank (no disturbance), but I'll try blocking off the vent and seeing!

11 minutes ago, Jon57 said:

Is the pump on constantly? If so have you turned the speed pump up to max. Sounds like the water might be getting too hot in the boiler. Can you check the flow and return temp at the boiler when the noise starts.

It is on constantly. It makes the noise even if the stove is cold, unfortunately.

[DShK]

After some research I have concluded that what I hear with the trickling is something called "waterfall flow" and is indeed caused by the build up of air. I will fit a manual bleed point and if it returns as an issue I'll fit an automatic bottle vent.