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by Antz
30 Jun 15 12:41 PM
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Latest Forum Posts

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54 posts
Posted Yesterday, 4:13 PM
Back of thumbnail calculations to nine decimal places … :)

Air is moved by a very basic generic HRV rated at 350m³/hour. Distribution is via three trunks – 300x100 + Ø150, Ø150, and through wall (no ducting). If by “commissioning” you’re asking if the system has been calibrated at each vent, then no. I’m still working on the interior of the house, so some of the air distribution is temporary and there is no point to attempting to finalise yet.

1 posts
Posted 4 Jul 15 4:44 PM
Hi Shaye,

I have just come across this thread, 2 years later! Your house sounds exactly like the type of thing my husband and i want to build! Have you built the house now? Would love to talk to you about it and ask you some questions. I don't even know if you will see this message! Hopefully :)

23 posts
Posted 4 Jul 15 2:26 PM
I get 0.74 ac/h, but may be due to rounding of interim results. Anemometer in isolation may not be the best way of measuring, though, but yes, this seems high. What air handling unit are you using, and what's your distribution looking like? Has the system been commissioned after installation?

54 posts
Posted 4 Jul 15 1:55 PM
Well, that was interesting .... velocity at the HRV exhaust (the only place I can measure) varies by about a factor of two depending on where in the air stream I measured. So I used the anemometer's averaging function, and used the lowest velocity I got from three sets of averages.

Anyway - I get 0.75 ACH, which seems high.

Someone may want to check my calculations. Exhaust diameter is 0.16m, average air velocity is 4m/s, and house volume is 390m³.

23 posts
Posted 3 Jul 15 4:06 PM

54 posts
Posted 3 Jul 15 3:57 PM
Floor area is about 155m², so that's around 10.5kwh/m²/year. Quite a bit lower than my earlier eyeball figure of 13kwh/m²/year - nice to see, particularly when knowing that it will improve as the place is optimised. Unfortunately I have no way of separating heating and cooling energy use.

For reference, this is in Feilding, so about in the middle of New Zealand temperature ranges. We rarely go below -2°, or above 28°. So not very hot, but also not very cold.

Indoor air quality is subjectively very good. Windows are (quite literally) never opened, simply because we never feel the need to, and that the indoor air is often better than the outdoor air - particularly in winter (wood burner smoke). I don't have any way of measuring Carbon Dioxide, but I can measure air flow and calculate the ventilation rate - won't be exact though. Will do that over the weekend if I remember.

23 posts
Posted 3 Jul 15 11:04 AM
That's great!
You seemed to have it comfortable. What's your indoor air quality like?

I'd be interested in a per square metre value and your measured ventilation rate or CO2 concentrations, alternatively.

54 posts
Posted 3 Jul 15 10:47 AM
If anyone is interested, I now have one full year of measured heating plus cooling energy use - 1620kwh.

Temperatures are:
* Sleeping target 19-20 (typically 19 in winter and 20 in summer).
* Non-sleeping target 22-24 (typically 22 in winter and 24 in summer).

1 posts
Posted 1 Jul 15 11:31 AM
Are you still looking for a straw bale house?

5 posts
Posted 30 Jun 15 12:41 PM
Hi Madmeg,
I agree with your comments and I provided feedback to Pyroclassic that their instructions are not adequate and may lead to problems such as the ones we had. Our fire is a pyroclassic iv. In the end, removing the top plate was straight forward. Only the stainless flue sections are cemented as per the instructions, nothing fancy. The lower cone to top plate spigot is a press fit with no cement, held in place by one screw at the back. We removed the screw and lifted the flue, resting it on a board supported by a stool placed either side of the burner. The top is then easy to remove, though beware that kaowool is likely to stick to the plate, therefore have a flat blade handy to scrape it off without damage. This requires two people to save torture. The lady kitchener is of similar concept design, but the top plate appears to have two sections, making this task easier without lifting the flue. If I were Pyroclassic, I'd develop a similar way to clean the top chamber easily, as inevitably creosote deposits will build up no matter how well you use the fire. I really believe that the ceramic firebox is a huge asset to this fire and that the design is worthy of further refinement to make it more service friendly and avoid many issues posted here. Whether they choose to do so is another thing, but they have at least addressed the blocked primary port problem.

11 posts
Posted 30 Jun 15 9:09 AM
which model have you got? ours was the iv. Our contact was through Pivot stoves in Chch that was the contact number available and I believe they are the company which now makes the things- they were unhelpful verging on rude in the extreme. The manufacturers sweeping advice distinctly tells you NOT to take off the top plate but to only sweep down from the top and says that any remaining creosote will burn off the water tubes (it would struggle with the amount that ours collected in 2 months of burning). Even after being swept and removed about 2kgs of clumped soot from the flue it would not burn properly (this was after two months of use).
They do not mention using any special compound on the joints in the literature, our installer was reputable and had fitted a number of the things without any problems- they were also disgusted at the lack of response to queries for help. It never at any stage required just an "armful" of wood for an evening but burnt it's way through more than half the winters supply in three months with minimal heat output.
I find your first paragraph patronising (in fact it is the same tone we got from pivot stoves when attempting to deal with them) yes, I have fire to keep me warm, that is its purpose, it is the only form of heating in our 2 storey house and needs to to do the job it was purchased for. The current "black box" uses far LESS fuel than the useless pyrocrap and puts out a good heat. It burns what we put in it and after using it for the rest of last season the soot was minimal when it was swept (there was a HUGE starling nest in it though!). The installer came back several times to try and fix the thing and gave us very good service- which is much more than can be said for pivot stoves who never got back to us when they had promised to and refused to acknowledge there might be a problem with the expensive and useless piece of crap we had bought.
It strikes me that the "fixes"you have had to do - take this off fiddle with that etc are all well outside the manufacturers own recommendations. when you spend as much money as you have to to get a pyrocrap then you should surely be getting a quality , well supported product not a fussy, fiddly heath robinson contraption

5 posts
Posted 29 Jun 15 10:26 PM
I understand some pyroclassic fire users like Madmeg are literally fuming with “pyrocraps” and prefer black-boxes that throw out huge amounts of energy, while consuming massive amounts of wood. To be fair, Madmeg’s photo suggests the retailer and installer should not have recommended a pyro with 100mm diameter flue offset in the manner shown, and creosote can only run down the outside of the flue if poorly installed.
This is the summary of causes / solutions to our pyro iv, I’ve now completely sorted. The pyro is a burner based on furnace technology and is actually very simple in design, but it is finely tuned. Three air sources, primary front ports above the door, secondary air tubes supplying hot air to burn gases just as they exit to the top chamber, and a turbo slide primary for starting and reloading.
As previously posted, after 2 years using a pyro iv, we encountered problems. During these problems, emails and phone calls to Pyroclassic in Hastings has been well supported. I believe three issues coincided to amp up the poor performance.
1) The flue was not cleaned properly. 2) The creosote wasn’t removed from the top chamber after cleaning. 3) The primary air ports effectively became blocked over time.
Addressing the flue, the 100mm dia is finely matched to the draw of a properly functioning fire. As soon as significant creosote builds up, the fire closes down, theoretically avoiding a flue fire. However, to counteract poor performance owners natural call on the turbo, which in our case started a flue fire. Creosote build up in the top chamber, likewise reduces flow and the wet-back heat exchanger becomes less effective. So once again the turbo is called on. Finally, the primary air ports behind the front cover. Our model has heat insulation behind the front cover to avoid heat damage to the front painted surface. When fitting the panel, you need to pull the centre of the panel out to avoid damaging the insulation on the spacer bolt, located between the primary air ports. The bolt is a tight fit on the insulation, and over time the insulation compresses, allowing the front panel clearance to the ports (7mm) to be reduced. This restricts air flow, requiring the use of the turbo.
My conversation with Pyroclassic found that the insulation is no longer fitted to the front panels, as testing found it isn’t required, and therefore avoids the risk of blocked air ports.
Our fire is back to operating as new. We have not had to replace handles or air tubes, and at present it is purr’ing along using only an arm full of wood for the night, heating the entire upper level of our house.

1 posts
Posted 29 Jun 15 11:57 AM
Mitsubishi Electric have a true balanced ventilation product called "Lossnay"

It is an ERV Energy Recovery ventilator

Used extensively in commercial ventilation solutions as well as domestic applications

Just putting right "mobiledean's" misinformation above

Pete Hutson Technical Manager BDT Mitsubishi Electric

1 posts
Posted 26 Jun 15 4:46 PM
Bit late to this thread, but I imported lamps from China directly. They provided an SAA certificate for the driver, and are saying that because the lamp is low voltage, the lamp itself doesn't require certification. Can anyone shed light on that?

11 posts
Posted 25 Jun 15 3:50 PM
or just go for something which is NOT a pyrocrap which is quite happy to burn any reasonable wood that you have felled and seasoned for a reasonable length of time. Something that does not require kiln dried wood which is neither pine, fir or (from our experience) eucalyptus or cut to a scientifically exact length :-). A fireplace that does not require specialist sealing compounds to ensure that the flue will draw properly.
Our Metro is happily burning away right now (windblown pine from about 12 months ago, cut from where is fell the other day and split at the weekend ), throwing out plenty of warmth, staying in overnight and boiling the hot water, something the pyrocrap struggled with after the first couple of weeks of use. No brainer which I'd rather have. I can't answer for Metros customer service as we haven;t needed to use it. Unlike pyrocrap's, which was crap.

5 posts
Posted 25 Jun 15 1:43 PM
You may have sorted this by now, otherwise see my recent posts, which may help.

5 posts
Posted 25 Jun 15 1:39 PM
Subsequent to yesterday's post I've found an article on the Net New to me, wood can be too dry, so the ideal is between 15% and 25%, which most burners are designed for. In brief - over dry wood rapidly releases gases that require sufficient oxygen for complete combustion that cannot be met by some wood-burner designs. This results in pulsating or hunting combustion and poor emissions that leads to creosote build up. Even if you meet the oxygen demand (open the turbo), the rsulting fire is very hot and can cause damage (burnt handles and failing air tubes). It seems that you are damned if you do....damned if you don't dry wood. So we are starting again - cleaning the flue, inspecting the upper chamber with a cheap USB cam for excessive creosote deposits from cleaning, cutting to ideal length wood of the recommended moisture range, and also checking the airtube inlet is not obscured by any misplaced kaowool or other. A bit of a fuss, but I'll post the results soon.

5 posts
Posted 24 Jun 15 10:24 PM
Hi All, we are in our third season of using a pryro iv with wetback, and overall we are very pleased with it. But, this season symptoms similar to some posts have arisen. That is, the need to use the turboslide for more than startup and reload and general sluggish performance, following two excellent seasons with no problems. We are not out of the woods yet this season, but here's what we have found. Providing flue cleaning instructions to our sweep lead to a fear of damaging the wetback heat exchanger and incomplete flue cleaning for two seasons. A few weeks ago, following email queries to pyroclassic (who have been responsive and very helpful), the bottom flue section started to crackle, creosote could be heard falling inside, and the lower flue started to glow. We were near ignition for a full on flue fire! Shutting the turbo down killed the heat. We purchased 3x1.5m rods with brush and cleaned the full flue length ourselves, which solved most of the problem. This was the most likely cause for sluggishness, that was provided to us by pyroclassic following our inquiry. The residual issue we believe relates to short lengths (300mm) of douglas slab wood. Moisture is <10%, but it is hard to use the full length of the firebox with short wood, which we were achieving during other seasons when the performance was excellent. We find the first 3 small loads of wood are run with some turbo to warm up the ceramic and develop an ember bed, following that the turbo is closed for normal operation. Burning the handle and damaging air tubes in a few seasons sounds symptomatic of running the fire on turbo and too hot. Creosote staining down the outside of the flue to the interior of the house is related to installation. As we've found out, modern silicone sealant around the rubber roof flashing gasket to the outter flue sleeve are unreliable and may lead to water leaks during wind and rain - easily fixed with a quality fit for purpose silicone product. Our installers were a couple of fussy boiler fitters. The Council inspector commented on the best install he had seen in years. I'll provide a performance update when our longer wood is fully seasoned.

2 posts
Posted 24 Jun 15 12:36 PM
Yes this public discussion is very valuable and a great resource (& I hope to add to it with my own experiences in future). Though I'd appreciate the chance to also chat directly if you're willing, please feel free to be in touch. (And apologies to others if distracting from this interesting discussion!)

54 posts
Posted 24 Jun 15 10:49 AM
No problem to discuss more, but give some thought to having the discussion here so others can see what worked and what didn't. If you prefer to chat directly, leave another comment here and I will send an email.

2 posts
Posted 23 Jun 15 11:44 PM
So much interesting and useful information shared here, thank you all. Leonard s, your particular approaches sound similar to something I really hope to build, and just wondering if you may be prepared to talk a bit more with me about your experiences; if so, please feel free to contact me at: (and suggest how I may get in touch), cheers.

3 posts
Posted 22 Jun 15 4:54 PM
I only want to spend about $7k on this.

Mate I couldn't agree more. I love radiators! But the gas companies have killed gas in Wellington. The connection fee alone is $1.7 a day, and you could run a ducted heat pump for fours just on that alone.

We just have single glazing in our house, but we do have good thick curtains.

48 posts
Posted 22 Jun 15 3:32 PM
For this expense you can install a simple central heating with radiators. This is far more comfortable and efficient than warm air blowing around.
Do you have insulated windows ?

78 posts
Posted 22 Jun 15 9:57 AM
A summary of our experiences so far with PV and an EV can be found on our latest blog

Comments welcome here or via our website, and feel free to retweet, repost link, etc.

3 posts
Posted 22 Jun 15 8:53 AM

We have a small-ish (110sqm) 1920s bungalow (almost fully insulated, just a few walls to go) , and would like to install a ducted heat pump to keep us warm.

The trouble is these systems are very expensive. We have had a number of quotes all ranging from $10k to 15k. From what I understand, the main reason for this price is it takes the poor installer a couple of days to put in all the ducting, who could have installed a large number of high wall units in the same time.

So here is my plan
1) I have a friend of a friend of a friend who will install the unit in our ceiling.
2) Our sparky will wire it in
3) I will install the ducting and vents.

However, the design of these systems is an absolute science. The velocity, pressure, ducting diameter and defuses etc. all have to be correct, otherwise it’s a waste of time.

Is there anyone out there who could help me? Or be able to point me in the right direction?


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