MCZ Musa Hydro 15kw - thoughts

dban

Hi,

I'm planning to move from oil fired central heating to a wood pellet powered system that will maintain radiator heating with modest domestic hot water provision.

The MCZ Musa appears to tick all the boxes so I'm looking for some real time advice from those kind enough to reply.

1. Is a 15kw output compatible with a 4 bedroom well insulated bungalow? Existing oil boiler is 50 Btu approx 16kw. On line calculators suggest an 11 kw requirement based on existing insulation levels double glazing underfloor insulation and 300mm loft insulation. Existing oil useage about 1500 litres a year.
2. This model of stove is intended for my lounge, so will be on display, any thoughts on installation, masking or hiding cables and the plumbing network behind the stove.
3. The flue outlet (80mm) will extend through the ceiling, loft and roof. What is the most visually attractive way of doing this given the flue has to be be double wall insulated to pass through the ceiling?
4. Thermal store - is it needed? I understand that wood pellet boilers do not need large thermal store tanks - but Imay link solar panels in in the future so....?
5. Bulk pellet storage (4 tonne) - combating damp? Damp west coast environment, storage in timber shed ok?

Many thanks in advance

dban

reeac

dban wrote: »

Hi,

I'm planning to move from oil fired central heating to a wood pellet powered system that will maintain radiator heating with modest domestic hot water provision.

The MCZ Musa appears to tick all the boxes so I'm looking for some real time advice from those kind enough to reply.

1. Is a 15kw output compatible with a 4 bedroom well insulated bungalow? Existing oil boiler is 50 Btu approx 16kw. On line calculators suggest an 11 kw requirement based on existing insulation levels double glazing underfloor insulation and 300mm loft insulation. Existing oil useage about 1500 litres a year.
2. This model of stove is intended for my lounge, so will be on display, any thoughts on installation, masking or hiding cables and the plumbing network behind the stove.
3. The flue outlet (80mm) will extend through the ceiling, loft and roof. What is the most visually attractive way of doing this given the flue has to be be double wall insulated to pass through the ceiling?
4. Thermal store - is it needed? I understand that wood pellet boilers do not need large thermal store tanks - but Imay link solar panels in in the future so....?
5. Bulk pellet storage (4 tonne) - combating damp? Damp west coast environment, storage in timber shed ok?

Many thanks in advance

dban

1. You're suggesting a 27% decrease in boiler power [from 16kW to 11 kW] which sounds dubious unless your past experience with the old system indicares that it's overpowered. I would trust past experience in the actual bungalow rather than some online calculator.
2. Siting the boiler in the lounge sounds attractive but it's a matter of architecture and personal taste as it may lead to a poor temperature distribution. We have a small wood burner for emergency use only [if electricity goes off] and I don't really like the uneven heat distribution although admittedly the wood burner doesn't power the radiators.
3 Can't comment on the flue as ours sits in a custom built brick fireplace and the S/S flue disappears up through a concrete soffit which isn't visible except from a low level.
4.Re. wood storage, all you need is a roof to keep the rain off. Our modest wood store is a 8x4 sheet of heavy ply supported on fence posts, topped with roofing felt and located in a sheltered position [no blown-in rain].

diywhynot

Have you had any professional advice?

reeac

I'm returning with a few more thoughts:
1. re. the flue. Seems to me that you need a circular S/S trim of generous size - say 300 mm. minimum where the flue goes up through the ceiling. This will permit a good clearance between flue and ceiling, maybe 50 mm. all round. Presumably there are building regs. re. this clearance. The trim should eliminate ceiling discolouration by convected dust particles.
2. Re. storage, I was thinking of logs which require drying and therefore ventilation. Wood pellets are already dry, I assume, and so may be better stored in a shed or other outbuilding.

dban

Hi,
Thanks for your responses.

No, I haven't had any formal advice yet. At this early stage I am simply looking for real time feed back before I commit to buying this system.

Regarding the change in boiler output my oil system has a 50 btu or 14.6 kw output. On line calculators suggest a CH need for 11 kw which seems fair based on living with this system since 1997.

My intended change is to the MCZ Musa 15.4kw wood pellet boiler stove which has a thermal/ CH output of 13kw which appears compatible with our existing heating needs.

On paper this system appears to be a good match - please tell me if I have this badly wrong!

dban

reeac

I'm a bit surprised that you can manage with that output as our 3 brm. bungalow, insulated to 1997 standards has a 60/80 oil boiler set to 75,000 BTU [22kW]. The difference probably shows up in speed of heating up from cold rather than in ability to maintain the desired temperature. Nevertheless, you've had plenty of experience with the existing system and that's the best guide.

bernithebiker

I've seen an automated MCZ wood pellet stove (think it was 8kW) in action, and was very impressed. It was in a friend's living room, and it blew it's heat around the room. You just needed to plug it in and take an 80mm flue out, easy peasy.

bgprior

Re (5), wood pellet bags are normally perforated with a number of fine holes. This is to release the air during the bagging process so the bags can be stacked as tight as possible.

Some pallets of bags are hooded and then wrapped, while others are simply wrapped. If your pallet is not hooded, or if you have removed or damaged the hood, you must keep your pallet under cover, as rain will hit the bags and gradually find its way in through the perforations.

Even small amounts of moisture will cause wood pellets to collapse into clumps of sawdust - they are hygroscopic (i.e. absorb moisture), and exothermic (i.e. release heat) when they come into contact with moisture.

For this reason, you should also be careful to avoid rising moisture from below the pallet. Ideally, pallets of wood pellets should be stored in a dry location.

You should also avoid storing them in direct sunlight, as the heat may drive off some of the remaining moisture (<10%), which will then condense on the inside of the bag and degrade the pellets. Pellets will also degrade if they are too dry. You should avoid extremes of temperature. A position out of the sun in a garage or shed is normally fine.

dban

Thanks bgprior.

I think the pellet storage requires careful consideration. The HSE have issued guidance following 3 tragic fatalaties from carbon. monoxide poisoning from entry into wood pellet stores. I think the smaller store held 7 tonnes!!

dban

bgprior

dban,

I agree, pellet storage always requires careful consideration. However, in this case, the issue is probably not bulk storage. They are likely to use bags with an MCZ Musa. A pallet of bagged pellets in a room somewhere is not likely to present the same degree of CO risk as a large amount of loose pellets in an enclosed space (e.g. a bulk store). If people are worried about CO in the room with the pallet, they could buy a CO alarm for the room.

If you are looking at risks that might be encountered with bags, I would look more at exposure to wood dust when "ripping and tipping" the bags into the hopper. Ideally, you should wear a mask and goggles when exposed to wood dust, and wash the dust off your skin at the earliest opportunity. The HSE also have a notice about this risk: "Wood dust: Controlling the risk" (WIS23). Like the CO risk in bulk storage, you just need to be sensible and follow the practical advice.

Chardeka

Hi Dban, you posted early this year about your thoughts on the mcz Musa. I've only just seen this thread. I have one and have lots to say about it so if you're still considering this, please read my experience below.

Firstly, with regard to output a qualified heating engineer would calculate the output you would need for both your heating and hot water requirements so best leave the decision as to which size boiler you need to the experts. That's virtually the only positive thing I can say about it, except that the design is very stylish and looks great.

I've had mine for 2 years, its in the lounge and if I could afford it I'd rip it out and replace it with a simple wood burner with back-boiler - no question whatsoever. I find the boiler noisy and rattly, which is a nuisance as its in the lounge. The programming is also astonishingly ridiculous: you can't choose when it comes on and off to fit around your own routine like you can with an ordinary boiler, but you have to choose one of mcz's own pre-programmed schedules, not one of which fits in with my rather ordinary work routine/lifestyle at all. And if there's a power cut, it won't work at all.

Also the pellets come in plastic bags which although can be recycled in some areas, they are still not good for the environment. I am a single person and live alone, and have always been careful with any form of energy consumption yet I go through 2-3 10kg bags every 2 days in Winter when the heating is on (I live in a small terrace house, with just a SMALL double bedroom and a box room). I pay £2.90 per bag, which makes this boiler a very expensive mistake for me. They are also quite heavy to bring in from outside (a stronger person may not have any problem but I'm a 48yr old woman).

As I write I've been utterly without heating and hot water for over 6 weeks. I am having supreme difficulty finding anyone to come and mend it - the original installers went bust, and absolutely no-one else seems to be qualified to fix it in the whole of Northern England. I've made between 35-40 telephone calls to loads of HETAS-qualified engineers, 'green' heating companies, and companies who are listed as installers of the same boiler etc. Only two have got back to me, neither could help.

Finally I emailed the manufacturer abroad for help to find someone, and was put in touch with the UK distributors who told me that there weren't any engineers in my area but "hopefully there will be 2-3 trained up in 4 weeks' time". I was genuinely shocked at the lack of engineers for aftercare as I live in the Leeds/Bradford/Halifax/Huddersfield area, which is densely-populated and also includes Hebden Bridge, where many environmentally-friendly people likely to want this kind of 'green' boiler reside.

A better solution - for me anyway - would be a wood burner with back boiler (I live in a city, so getting free wood out of skips would be a simple process), with an electric shower for keeping clean in the warmer months when the heating is off (I'm lucky that I have a dishwasher, but boiling a kettle would also be enough for me to wash up in the summer too).

I don't know if you have made up your mind, but if you're still undecided I hope this helps.

Kind 'cold' regards,
Tina :eek: