boiler vent size

[Kev888]

Hi,

Well I'm finally getting somewhere with my new boiler build. I plan to keep the top on and connect a pipe into it as a vent that I can direct outside; I've played with this idea before with 40mm plastic waste pipe and it seemed to work provided you angle the tube downwards so that condensation runs away from the boiler rather than back into it.

But this time I'm wondering about using 22mm copper pipe; partly because metal seems more suitable for steam, partly because it'd be easier to drill a smaller hole through the wall, and partly because I may try running it through the coil I took out of a hot water cylinder (placed in a tub of cold water, to see if I can condense some of it and reduce fragrant emissions).

I just wondered if anyone had ever done a rolling boil with a vent this small though, or have any other experience to help suggest if its likely to be big enough or not? I don't mind steam coming out rapidly, but I don't really want to cause too much pressure in the boiler..

Cheers,
Kev

[leedsbrew]

What are you using as a boiler kev?

[brewzone]

I'd say 22mm is probably big enough!

If a rehydrated hop cone can pass through the fittings used to connect the 22mm to the lid etc then I can't see a problem.

The clever chap at Eastgate homebrew in Stafford told Me a trick which is to put a weight from a set of old brass scales say 1 pound for example on top of the lid.

The pressure inside the boiler will be vented as soon as the combined weight of the lid and the 1 pound weight is reached I.E. 1.25 pounds.

If a 3 pound weight was used then this would be 3.25 etc

This was for a stainless boiler rather than plastic as the lid may not take the weight when hot.

BZ

[Kev888]

Thanks for the thoughts everyone - very useful.

What are you using as a boiler kev?

Its this type of thing, though mine is a 25gallon version - I got it quite a while ago and haven't had much time to do anything with it until now. Its a heavy industrial job with a stainless drain tube already welded in the bottom, but wasn't cheap (it was the cost that spurred me on to try that copper cylinder for the HLT). Its got a 6" opening and I can (just) reach to the bottom through it, so I thought I'd try leaving the top on instead of cutting it off - which makes fixing a vent easier and allows for more insulation. I may live to regret that when it comes to cleaning, but we'll see. I'll post some pictures of the conversion as I go.

I'd say 22mm is probably big enough!
If a rehydrated hop cone can pass through the fittings used to connect the 22mm to the lid etc then I can't see a problem.
The clever chap at Eastgate homebrew in Stafford told Me a trick which is to put a weight from a set of old brass scales say 1 pound for example on top of the lid.
The pressure inside the boiler will be vented as soon as the combined weight of the lid and the 1 pound weight is reached I.E. 1.25 pounds.
If a 3 pound weight was used then this would be 3.25 etc
This was for a stainless boiler rather than plastic as the lid may not take the weight when hot.

Thats a good idea. I'll probably make the lid removable for hops etc and it is stainless so that should be okay, but I'd not thought about a fail-safe pressure release dubris. If I don't make the lid as solidly connected, maybe held down by weight or magnets or something...

Not knowing the exact nature of the components driven off duing the boil I'd suggest plastic/polypropylene rather than copper given its resistance to corrosion (unless you have stainless available to you). I'd also suggest a larger vent than 22mm although not for the purposes of pressure reduction, unless the lid is sealed the steam will find its own way out and give you an indication of whether you need to address that. However unpleasant tasting chemicals are driven off during the boil and i'd want to make sure that they can escape and that there is no way they can drip back into the boiler as they will easily ruin a batch. That's not to say 22mm wont suffice but it certainly seems a little small to ensure expedient removal of the volume of steam that is produced during the average boil.

Ah yes, I was thinking more of the heat and hadn't considered corrosion - guess plastic would have some advantages and could probably cope with the heat long term - cheaper as well - although if I did use copper I guess I could design it to be easily swapped out every few years. Yes, the drip-back was something I encountered with my tests on the last boiler; angling the pipe downwards from the boiler almost completely solved that, anything condensing (presumably including driven-off nasties) ran away from the boiler rather than back to it. I think provided the steam can escape fairly freely it wouldn't actually stop stuff being driven off, but i can see that too much of a restriction could restrict steam and its undesirable companions escaping as easily.


Hmm, so it doesn't seem too ridiculous, but may be a tad on the small side. Perhaps I'll carry on with the idea then, but either go for larger plastic pipe or just put a tank connector in the lid to test before actually buying/running any copper pipes.

Thanks Again,
Kev

[fen_boy78]

I use plastic waste pipe and find it works well. Pipe turns a but green but thats it. No problems with the heat.

Mark

[Kev888]

I use plastic waste pipe and find it works well. Pipe turns a but green but thats it. No problems with the heat.

Mark

Thanks Mark, thats good to know. I only really experimented with the plastic pipe a few times, so its reassuring to hear that it works in the longer term; I had thought it may suffer more than that. maybe I'll give up on the idea of cooling the steam through my coil, and just go with a sensible sized waste pipe.

Cheers
Kev

[FUBAR]

I was going to do my first AG brew today,but after testing the boiler with water last night the amount of steam and condensation produced within half an hours boil was bad enough.Although I am using my outbuilding there are tools/freezer ect in there that will be buggered with all the steam,so I had a trip to B&Q today and got some 32mm plastic waste pipe,elbow joint and a tank connector and fixed it to the lid of my boiler.
Test run with water and it works a treat,no steam out of the side of the lid even with the lid just sitting on top of the boiler,I did notice a couple of puzzled looking neighbours looking at a piece of plastic sticking out the window bellowing coupious amounts of steam ,question is am I going to be ok with this set up regards to off flavours with some of the "nasties" not being driven off in the boil?.
Going by the amount of steam coming out of the pipe it doesnt seem to be much of a restriction,surely anything that condenses on the lid is going to fall back in the boiler and will be boiled again (refluxed)so the "nasties" stand a good chance of being driven off?.Hope it is ok as there is no way I will be able to brew with just the boiler with the lid off

Cheers FUBAR

[boingy]

32mm pipe will be fine as long as you keep a healthy amount of steam going through it. I use 32mm vented out of the side of the boiler (it makes the lid easier to handle). I run the pipe slightly downhill so anything that condenses does not run back into the boiler. DMS is generated at well below boiling point so as long as you keep the steam flowing any DMS will still be driven off. I always remove the lid for the cooling stage because I'm not sure what happens in DMS terms as the temperature drops.

[FUBAR]

Cheers boingy
Thats good to hear that all should be ok,I have about 6" of pipe sticking out of the tank connector then the elbow joint so as it reaches the height of the window sill then about a metre of pipe sticking outside,which due to leverage angles downwards.As well as the steam there was a constant drip of water coming out of the pipe,so next saturday should be first brew day ,the neighbours noses will be twitching as a cloud of hoppy steam drifts across the fence .

Cheers FUBAR

[boingy]

The only problem I've had with mine is where the boil has been a bit vigorous and the outlet pipe got blocked with hops. You soon know about it because the lid starts jumping around!

Edit: here's a link that covers similar stuff and also contains a link to piccies of my boiler and steam outlet

www.jimsbeerkit.co.uk/forum/viewtopic.php?f=6&t=34208

[WishboneBrewery]

Hmm, boiling with the steam not filling the garage!!? I sort of forget about steam until I see the bear plasterwork start showing damp patches! Then I know its time to open the door and vent off for a while! I did specifically sight my boiler right under a window which I open once on the boil, a bit of Lid-re-engineering might be a clever idea

[FUBAR]

The only problem I've had with mine is where the boil has been a bit vigorous and the outlet pipe got blocked with hops. You soon know about it because the lid starts jumping around!

Edit: here's a link that covers similar stuff and also contains a link to piccies of my boiler and steam outlet

viewtopic.php?f=6&t=34208

Nice set up boingy,think I should be ok my boiler is 10 gallons and there is a hell of a lot of free space to the top of the boiler

[Kev888]

Yes, I like it too Boingy - inspired by it in the past I played with bits of pipe in a similar setup and it worked well but I never made it a proper job. However, after the first brew in the garage recently I'm going to have to do it properly now, or else I'll take a shower in the dirty drips from the ceiling every brew day.

I'd not thought of also steam-cleaning the car at the same time though

Cheers
kev

[chivelegs]

Having the same problem here with steam. Got an old burco boiler and was considering a steam pipe coming from the lid. How did you attach the pipe to the lid of your boilers? Any pictures gratefully recieved!

[Kev888]

well personally I've just bought a new basket strainer for my kitchen sink, so I'm going to use the old one to fit in a hole in the lid. I just bought a shallow bath trap too, which will be used upturned to fix to the strainer, and its even got a little access hatch for poking in my thermometer probe. I've not actually done it yet though, last time it was just a rough test mainly relying on gaffa tape and any old odds and ends I had, so there could be things I've not thought of. One is that the basket strainer has inner and outer shells where nasties could lurk between so I'm going to have to fill it with silicone or something.

I do like boingy's idea to use the rim rather then the lid though, seems more practical really, I just don't want to drill another hole in my boiler wall.

Cheers
Kev