Hotbin has not been hot since August

[David's Dahlias]

So I got my hotbin in mid-July. It took about two weeks before it was reading internal temperatures of 60C. All through August it maintained its vigour, greedily reducing everything I threw into it. Me and my hotbin were best buds!

But those were the halcyon days. Since the beginning of September I haven't had it above 40C. For the last few weeks its internal temperature has scarcely hit 30. I'm absolutely mystified as to why.

I'll list the things I'm told the hotbin needs and describe how I'm addressing them.

External temperature
Sure, it was hotter outside in summer. But the temperature outside scarcely dropped in September. And the hotbin is insulated and is supposed to operate even in winter. So I don't think it's that.

Bulking agent
I've used a lot of bulking agent. I've used the whole bag that came with the bin. Since then, I've been using wood chippings I blagged off a tree surgeon in the park. I took half a wheelie bin full of wood chippings off the tree surgeon, and I've nearly got through that. So, since mid-July, I must have put the best part of half a wheelie bin's worth of wood chippings into my hotbin. I'm pretty sure I've been providing enough bulking agent.

Composting material
I have an allotment and a family. Out hotbin mainly gets fed food waste (about two full caddies a week) and leafy material (weeds, cut grass, nettles etc) from the allotment. This is all supposed to be stuff the hotbin loves. Frankly, it should be going apeshit. So I don't think it's being fed the wrong things.

Frequency of feeding
Generally twice a week, with the material described above.

Correct moisture level
I'm aware that he material I'm giving it (see above) is on the moist side. Fortunately, I own a shredder and we get no shortage of junk mail and I have years of old bank statements. So I use plenty of shredded paper - I think 50% by volume compared to the food waste / plant waste etc I'm putting in the bin. I'm also ripping corrugated cardboard into little bits and chucking that in. So if there's a problem with the compost being too moist, it's certainly not because I'm not providing the recommended amount of shredded paper.
The paper is the office-grade stuff, and judging by the one load of compost I've removed from the bottom of the bin so far, it's all broken down nicely. That compost, to my surprise, was not especially wet (not slimy or anything), but I'm new to composting so I'm not sure what level of moistness to expect in the finished product.
Having said all that, it does appear that the bin is producing an awful lot of leachate. The concrete floor the bin sits on is stained brown with the stuff.

Airflow
(Obviously also related to moisture level above.) This is where I suspect the problem may be. If the bacteria don't get enough oxygen, they can't process the stuff quickly, right? I removed perhaps 9 inches of mostly-composted material from the bottom of the bin a week ago, hoping that would improve airflow and get the temperature up, but it hasn't made any difference whatsoever. I've just recorded the internal temperature of the bin and the thermometer grudgingly hit 30C.
Does the compost in the bin not block airflow as the bin fills up? If so, what can I do about it?
I'm also wondering if some component of the bin itself is blocked. Is there a part of it - the grill at the bottom for example - which can get blocked up and block the airflow? Should I be somehow accessing components of the bin and checking / unblocking them?
Is there a way I can check directly whether airflow in the bin is impeded?

The reason I paid £180 for the hotbin was because I wanted to be able to compost the ghastly perennial weeds my allotment grows with gay abandon. The temperature is now too low for me to be able to do that, so my hotbin is now effectively a white elephant taking up space in my garden. I'm really not happy about it.

Has anyone else been in this situation and been able to reverse it? Can anyone suggest a remedy based on the information I've provided above?

Thanks in advance,

David

[David's Dahlias]

Some other points that may be relevant.

1) Since the beginning of October, I've been putting in the quick start bottle full of hot water every time I feed the bin.
2) The allotment waste that goes in gets chopped to bits using a pair of shears first.
3) The bin is in a sort of alcove in our garden between three walls. Does it need to be in a position where the wind can get to it more?

[gregcope]

I had a similar issue; Lots of leachate, temp not above 30C when I have had it as high as 65C.

I removed a trug full from the bottom and gave the rest a good mix with lots of wood chippings and some paper and off it went again, within a days reaching 40degC.

I think it must have gone anaerobic, and that the airflow from the bottom was limited/stopped so that composting stopped.

[David's Dahlias]

Thanks gregcope.
This morning I have:
a) Removed a couple of trugs of semi-rotted material from the bottom of the bin (a disgusting job). It was pretty wet, mind.
b) Shredded loads of paper and ripped up tons of cardboard, and chucked it in the top.
c) Put a couple of spades of the least rotted material back in the top and stirred it all in.
d) Put a bit of fresh waste in the top with the quick start bottle full of boiling water.

I'll report back in a couple of days.

Cheers

[David's Dahlias]

This link provides useful information about signs the contents of the bin are too wet, and also talks about the possibility of the grill at the bottom getting blocked up.

[David's Dahlias]

Do posts with links in them require moderation? The post I'm trying to link to is called 'How do I fix wet waste in the HOTBIN?'.

[EnlightenedElm]

Hi David,

Unfortunately posts with links in them do require moderation from the HOTBIN Team as we have seen bots trying to link users to spurious sites in the past. Regrettably to protect our users, we have had to make it such that linked posts need this approval prior to them being published. We have however made your initial post and link visible in the above trail.

We have a couple of questions for you:

How often is bulking agent and shredded paper/torn cardboard being added into your HOTBIN?

Are the paper and bulking agent being mixed in with the fresh waste or layered on top?

You mention that there is quite a lot of leachate leaving your HOTBIN - would you estimate that more than an espresso cup worth is being generated each week?

When taking an internal temperature reading, to what depth is the internal thermometer stem being inserted into the waste?

How full is your HOTBIN at present?

How far open is the aeration valve on the lid?

You also mention that you have been adding the kick start bottle each time you 'feed' the HOTBIN - unfortunately, if the HOTBIN's internal temperature is above 15°C when the bottle is added, it will have a negligible effect on the unit's internal temperature. The bottle is a tool designed to help generate heat when the unit is being started or restarted. Once the internal temperature is above 15°C, the temperature internally is imfluenced by the types and quantities of waste being added, the volumes of bulking agent and shredded paper being added and the aeration.

Please be assured that the location of your HOTBIN should also have a negligble effect on the performance of your HOTBIN as the generation of heat as a by-product of the digestion process is a purely internal process.

We look forward to hearing from you and hope to be able to help soon.

The HOTBIN Team

[David's Dahlias]

So I checked the bin on Wednesday. Its internal temperature was just over 30C.

I also checked and fed the bin this evening (Friday). Its internal temperature was between 35 and 40C. Worth noting that the thermometer was not that far from the quick start bottle, so the reading might have been artificially high. But it feels like progress.

I took a good look at the grill at the bottom tonight. I could shine a torch through it and see space. It's definitely not backed up with silt. I dabbed some neat bleach on it anyway. Belt and braces.

EnlightenedElm: thanks for your questions. I'll respond to them here.

How often is bulking agent and shredded paper/torn cardboard being added into your HOTBIN?

Every time I feed it.

Are the paper and bulking agent being mixed in with the fresh waste or layered on top?

I chuck it all in and give it a good mix with the proddy stick thing.

You mention that there is quite a lot of leachate leaving your HOTBIN - would you estimate that more than an espresso cup worth is being generated each week?

Definitely. The weather in Bristol is dry today and so the ground around the bin was dry. But in front of the bin there was lots of leachate. I was really surprised because I removed a couple of trugs of sticky not-quite-rotted compost from the bottom of the bin over the last weekend (i.e. 5 days ago).

When taking an internal temperature reading, to what depth is the internal thermometer stem being inserted into the waste?

Until the thermometer stick is about half in. This evening I reckon there was 4-5 inches of stick proud of the top of the heap. It's not just a thermometer issue. In August I would open it and it would be noticeably warm and visibly steaming. It's not like that anymore.

How full is your HOTBIN at present?

After feeding this evening, about 3 quarters.

How far open is the aeration valve on the lid?

The top surface of the valve is about 2mm away from the top surface of the bin. I've experimented with a number of different levels of openness!

You also mention that you have been adding the kick start bottle each time you 'feed' the HOTBIN - unfortunately, if the HOTBIN's internal temperature is above 15°C when the bottle is added, it will have a negligible effect on the unit's internal temperature. The bottle is a tool designed to help generate heat when the unit is being started or restarted. Once the internal temperature is above 15°C, the temperature internally is imfluenced by the types and quantities of waste being added, the volumes of bulking agent and shredded paper being added and the aeration.

Thanks for the tip. I removed it this evening.

Please be assured that the location of your HOTBIN should also have a negligble effect on the performance of your HOTBIN as the generation of heat as a by-product of the digestion process is a purely internal process.

Okay. One thing worth mentioning is that the concrete the bin stands on, although flat, is very slightly sloped in a way that tilts the bin forward. But I mean very slightly. You wouldn't notice it unless you were looking for it.

[David's Dahlias]

I fed the bin again today. The internal temperature was 30C, and the stuff I put in a few days ago didn't look like anything had happened to it.

I have so far:
* checked that the composition of bulking agent, paper / cardboard and food / plant waste is as per instructions. In fact, I'm now using a much higher proportion of paper and cardboard than suggested in the instructions
* removed nearly half a binful of material from the bottom of the bin, in varying states of decay
* bleach-cleaned the vent at the bottom

I am now out of ideas. I have no idea why the bin is not doing its job. Any suggestions very gratefully received.

[HotBin]

Hello David,

Just finished reading your little tale of woe, well done for persevering! How are you getting on now after your last course of action?

Sounds like you are definitely doing everything right from a feeding the bin point of view, there must be an airflow blockage somewhere preventing it from going above 40C.

When you emptied the bin did you notice whether the holes in the sqauare airation base plate were blocked in any way?

When you started the HOTBIN did you create a thin layer of twigs or prunings on the bottom of the base prior to adding in your first load of kitchen / garden waste? This normally improves airflow and prevents waste from sitting directly over the aeration holes.

I am hoping that by removing half a bin full of waste that you will have removed any air flow issues.

There is a good video on the HOTBIN YouTube channel that promotes a method of getting you compost bin back up between 40 and 60°c, I don't whether watching this would help in any way.

https://youtu.be/A5bJ5A1CNvE

Please keep us posted and share with us how you are getting on now, fingers crossed the dial is starting to creep over the 40°c line for you!

Very warm regards

The HOTBIN Team

[David's Dahlias]

Just finished reading your little tale of woe, well done for persevering! How are you getting on now after your last course of action?

I checked the bin today. The internal temperature was just over 30C. I'm starting to run out of space in the bin now.


Sounds like you are definitely doing everything right from a feeding the bin point of view, there must be an airflow blockage somewhere preventing it from going above 40C.

I guess so...


When you emptied the bin did you notice whether the holes in the sqauare airation base plate were blocked in any way?

No, I didn't. I noticed the holes but didn't notice any specific blockage. They're quite long / deep though aren't they? I'm not sure how I would spot a blockage further down.


When you started the HOTBIN did you create a thin layer of twigs or prunings on the bottom of the base prior to adding in your first load of kitchen / garden waste? This normally improves airflow and prevents waste from sitting directly over the aeration holes.

Yes I did. I pulled a lot of them out when I emptied the bin for the first time a month or so ago. After removing compost, am I supposed to replace the twig layer? I haven't read anything about that.

If in future I do suspect the aeration holes are blocked, what do you recommend? Stuffing toothpicks or something in their to try and clear them?


I am hoping that by removing half a bin full of waste that you will have removed any air flow issues.

There is a good video on the HOTBIN YouTube channel that promotes a method of getting you compost bin back up between 40 and 60°c, I don't whether watching this would help in any way.

Yes, I've seen the video. It seems to be mainly concerned with the composition of materials that go in the bin, rather than dealing with blockages. I'm now actually using a much higher proportion of paper/cardboard to waste than shown in that video because I still seem to be getting a fair bit of leachage. One thing I haven't tried is chicken pellets. I'll look out for them next time I'm at a garden centre.

On the subject of chicken pellets, I assume being dry that they can also be used as a partial substitute for paper / cardboard?

[nfetto]

My story is very similar.

I have just reached the depressing point at which the Hotbin is clearly 'going out' just as my waste reaches the 40cm point. I have had measurements of between 30 and 40 on the way up, have had lots of leachage, have used more shredded paper and wood chips than recommended, have nevertheless done a further 'rescue' dose of shredded paper and wood chips a few days back when I thought I could smell a bit of 'drain' when opening the lid, and I'm not getting anywhere.

I wonder:

1) Am I suffering from not using cardboard as well as shredded paper? Is there something magic about cardboard?

2) Could there be an aeration problem that is NOT due to any of (a) the gauze plate, (b) the holes at the bottom, (c) the waste, or (d) the valve?

3) In view of the amount of leachage that I and David are getting, is there a fundamental principle that we are missing, namely that (like a fire) if your Hotbin does not start hot, it is very unlikely to get hot, because the sub-40 degree waste that you are building up is generating so much moisture without enough heat to lift it out of the bin that you are destined to end up with an anaerobic bin? In other words, it is like trying to build a fire having failed to get it going at the outset because your original wigwam of twigs was damp?

Finally, I have an additional possible adverse factor, namely that one of the ridges on the inside of my hatch door is cracked. I don't think it is affecting the seal, and my cam-straps are tight, but could that be a cause/contributor?

Sorry not to be providing answers. I would love to hear some though!

N

[David's Dahlias]

Today for the first time I put a caddy of kitchen waste out for recycling. The hotbin is still full from its last feed because it's not processing the waste properly.

So in view of the fact that I've followed the operating instructions, but the unit is not operating correctly, is it time to start talking warranty? I understand the unit has a warranty of one year, apart from certain components which have a guarantee for three years?

What information do I need to provide?

[nfetto]

I may have an answer for you. My Hotbin is now going great guns after the best part of two years' trying on my part.

In relation to the questions I asked in my post above:

1) There is nothing magic about cardboard. I am using shredded office paper in greater quantity than recommended.

2) The problem was none of the things I listed. It was the charcoal filter. It had completely blocked the airflow. I removed it and within 24 hours the internal temperature went from 35C to 60C. The maggots that were there are a distant memory now - the temperature yesterday hit 68C.

3) How you start the bin is obviously important, but in my case it was not the problem. I had got the proportions right enough (I had erred on the side of caution throughout with the wood and paper) but the mixture was stagnant and becoming too damp because the air was not flowing through the bin from bottom to top.

NB: According to the Hotbin website you invalidate the warranty if you remove the charcoal filter bag. See http://www.hotbincomposting.com/blog...is-needed.html. I was taught by one of the Hotbin customer assistance people to remove and dry the filter bag when restarting. You may wish to pick up the phone to them.

This is a problem that has happened to others, it seems. See the bottom post on this page: https://forum.hotbincomposting.com/f...otbin-champion.

Hope you get there. Worth it when you do. Soul-destroying at times beforehand.

N

[David's Dahlias]

Oooooooooookay. This one is straight from the 'head in the sand' approach to customer services. Can't help you fix your problem! We'll ignore you!

I've also checked my emails: nothing there.

Still, this stands as a matter of public record I guess. Good luck you guys.