New system (gassifier) in an old house

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.
OldStoneHouse

OldStoneHouse

Member
Jan 8, 2010
91
Eastern Ontario
I'm starting to plan a new boiler install and hoping that you may have some suggestions. Here's the background first:

Last year we had a Caddy hot air oil/combo installed in our house. In a nutshell, the contractor didn't do a heat loss and the furnace is too small. We had him back shortly after it was installed because we were having trouble with the heat output (imagine). He put it down to the wood not being dry enough. In hindsight I should have insisted on a heat loss but we accepted his word that it would "give us lots of heat." This year, with dry wood, its better but still needs feeding every two-three hours and it's not even cold yet! Needless to say, we're pursuing the contractor but so far he is avoiding us. In the meantime we need to figure something out for next winter, this winter my wife is home and can feed it regularly so it's not too bad.

The house is 160 years old, stone, two stories, and about 2,500 square feet and we've done about all the tightening up we're able to do. I've done a heat loss using the HOT2000 software and it comes out to 120 000 BTU, the Caddy oil is about 70 000 BTU but that's not heating the entire house really. The forced air duct system is primitive at best - there are only two supplies to the second floor and no returns. One of our bedrooms was regularly 12 degrees Celsius last winter (53 Fahrenheit). Installing more ducts would be complicated given the layout and likely destructive.

One suggestion that we had was to install a hot water system. This seems like a good solution since I'm pretty such it's much easier to run 3/4" pipe than 6" duct. Since the house is old, we would like to use cast iron rads because they will look more appropriate.

I'm looking at the Tarm Solo Innova or the Solo Plus from the conversation I've had with the local dealer. I want to do storage because I have an unused cistern that's about 1000 gallons that is in the same room the boiler will go in. The dealer was suggesting perhaps going larger with the boiler because of the storage. So should I think about the Innova 50 or the Plus 40 or 60?

As far as the backup heat goes I'm looking for some advice here too. In another thread someone had suggested that a backup boiler could be sized smaller since it would only need to be used occasionally. I'm thinking of the Weil-Mclean CGI series in propane. Oil is a possibility but venting becomes more difficult. I know that someone else was using a tankless water heater as a backup but I suspect that may not be a great idea. The wood will be the main boiler so I don't see a need in getting the most efficient backup boiler known to man for it only to be used a week a year. Could I get away with a CGI-4 (74,000 BTU) or should we go bigger?

We are hoping to do as much of the work ourselves as possible once a proper design is worked out. I'm actually enjoy soldering, so copper is fine for most of the system. I think pex would be easier for the lines to the second floor.

Does anything here not make sense or not belong? I'm hoping that we can start with a basic system and then expand as more time and funds become available. Am I missing anything obvious that we should be looking at?

Thanks for your help!
 
Have you considered a combination wood oil boiler? New Horizon (an advertiser here) has his Biomass unit. Wood Gun also has a combo unit.
A hydronic system is superior to hot air and as you said will be easier to install. I'd do at least 2 zones. Pex will be easier to run in some areas and is actually cheaper than copper.
I can tell you first hand that the EKO is a quality unit at a fair price.
Good luck!
 
Since you have 1000 gallons of storage, I would definitely go with the Solo Innova 50. The Solo Plus is a good choice if you are NOT going to use storage, but the Solo Innova is a bit nicer boiler and the one to choose since you have such generous storage.

I would strongly recommend choosing a 120,000 BTU propane boiler as back-up. I think the difference in cost between a boiler that will meet your entire heat load and the 74,000 BTU unit will be minimal and you never know when you may have to heat completely with propane for some reason (injury, illness, travel, resale). Propane is definitely the better choice if you are going to powervent.

I also agree that converting to a hydronic heating system is the way to go. I might recommend panel rads instead of cast iron, but I can see that the cast iron might look better in your style home and that is, of course, important too.

good luck with the project, it sounds like a great move for you and your family.

Chris
 
I have a Rennai 94 (190K BTUH) as the backup for my house (actually heated the house for two seasons before the boiler). It works great as the backup or primary unit. I now run all my domestic hot water through the Rennai before going to the fixtures. The input to the Rennai is preheated by the storage and mixed with a tempering valve to 130F. I can also run the radiant heat this way and the Rennai will boost the temp to 130F if needed. I don't see the value of a true gas boiler as the backup unit, particularly with storage. Radiant heat will bypass the Rennai (via a Taco EBV) if the sorage is greater than a setpoint. With radiant floors my usable temps are as low as 100F.

Classic cast iron could be nice. The lower temperature flat panels can look nice - gives a modern European look which can actually work with the stone house. They work at lower temps than the cast iron. If you have a loop for each emitter/room you may be able to use 1/2 PEX. You will have to do the heat loss calcs by room to see how many BTUs you need to deliver to determine which size supply you will need.

I like my Paxo 40 unit - no complaints so far. How well will you be able to insulate your cistern?
 
Thanks Hydronics: I hadn't considered those but only because I didn't realize gassifier combinations exist. I'm constrained by height (~82 inches) and flue diameter (6 inches) but I'll definitely look into them.
 
...and width probably - it will have to fit in to old doorways.
 
The cistern should be fairly easy to insulate because it basically a cement box in the basement. I could insulate on either the inside or the outside, I'll have to think about that!

Any problems with the Rennai using it that way? I thought I read something about that could cause it to fail because it wasn't designed for that kind of flow?
 
Tarm Sales Guy said:
Since you have 1000 gallons of storage, I would definitely go with the Solo Innova 50. The Solo Plus is a good choice if you are NOT going to use storage, but the Solo Innova is a bit nicer boiler and the one to choose since you have such generous storage.

I would strongly recommend choosing a 120,000 BTU propane boiler as back-up. I think the difference in cost between a boiler that will meet your entire heat load and the 74,000 BTU unit will be minimal and you never know when you may have to heat completely with propane for some reason (injury, illness, travel, resale). Propane is definitely the better choice if you are going to powervent.

I also agree that converting to a hydronic heating system is the way to go. I might recommend panel rads instead of cast iron, but I can see that the cast iron might look better in your style home and that is, of course, important too.

good luck with the project, it sounds like a great move for you and your family.

Chris
Click to expand...

Thanks - that's all very helpful to know. I think it would only be $400 difference so it really won't matter too much. I don't think panels will work for us but we might use a few cast baseboards though.
 
Brad said:
Any problems with the Rennai using it that way? I thought I read something about that could cause it to fail because it wasn't designed for that kind of flow?
Click to expand...

The Rennai has a shorter warranty period when used as a heating appliance, but otherwise it works. There is a high head pressure at high flow rates but it works nicely up to about 6GPM. If I a add a booster circulator I can gt higher flow (my max need on radiant is 9 GPM) but we have worked fine without it. For radiant, you are only looking at a 20F deta T as opposed to a 80F delta T for DHW from ground temp. The Rennai modulates the fuel to obtain the desied set point so you are not running a 200KBTU output most of the time (more like 30 - 60K BTU). I had my first problems with the Rennai this fall (3rd season). A dead cricket in the blower caused a wobble and a lot of noise and a dirty sensor (cleaned with some abrasive cloth) in the burn chamber. You could plumb with a 3-Way or some other arrangement to bypass the Rennai when not needed. I like having my DHW run through so it will fire once in a while (to keep it working).
 
Brad said:
I'm starting to plan a new boiler install and hoping that you may have some suggestions. Here's the background first:

Last year we had a Caddy hot air oil/combo installed in our house. In a nutshell, the contractor didn't do a heat loss and the furnace is too small. We had him back shortly after it was installed because we were having trouble with the heat output (imagine). He put it down to the wood not being dry enough. In hindsight I should have insisted on a heat loss but we accepted his word that it would "give us lots of heat." This year, with dry wood, its better but still needs feeding every two-three hours and it's not even cold yet! Needless to say, we're pursuing the contractor but so far he is avoiding us. In the meantime we need to figure something out for next winter, this winter my wife is home and can feed it regularly so it's not too bad.

The house is 160 years old, stone, two stories, and about 2,500 square feet and we've done about all the tightening up we're able to do. I've done a heat loss using the HOT2000 software and it comes out to 120 000 BTU, the Caddy oil is about 70 000 BTU but that's not heating the entire house really. The forced air duct system is primitive at best - there are only two supplies to the second floor and no returns. One of our bedrooms was regularly 12 degrees Celsius last winter (53 Fahrenheit). Installing more ducts would be complicated given the layout and likely destructive.

One suggestion that we had was to install a hot water system. This seems like a good solution since I'm pretty such it's much easier to run 3/4" pipe than 6" duct. Since the house is old, we would like to use cast iron rads because they will look more appropriate.

I'm looking at the Tarm Solo Innova or the Solo Plus from the conversation I've had with the local dealer. I want to do storage because I have an unused cistern that's about 1000 gallons that is in the same room the boiler will go in. The dealer was suggesting perhaps going larger with the boiler because of the storage. So should I think about the Innova 50 or the Plus 40 or 60?

As far as the backup heat goes I'm looking for some advice here too. In another thread someone had suggested that a backup boiler could be sized smaller since it would only need to be used occasionally. I'm thinking of the Weil-Mclean CGI series in propane. Oil is a possibility but venting becomes more difficult. I know that someone else was using a tankless water heater as a backup but I suspect that may not be a great idea. The wood will be the main boiler so I don't see a need in getting the most efficient backup boiler known to man for it only to be used a week a year. Could I get away with a CGI-4 (74,000 BTU) or should we go bigger?

We are hoping to do as much of the work ourselves as possible once a proper design is worked out. I'm actually enjoy soldering, so copper is fine for most of the system. I think pex would be easier for the lines to the second floor.

Does anything here not make sense or not belong? I'm hoping that we can start with a basic system and then expand as more time and funds become available. Am I missing anything obvious that we should be looking at?

Thanks for your help!
Click to expand...
I don't think you would ever be sorry for installing cast iron rads, they are nice! From what I have read you can size the wood boiler up to 50 percent greater than the heat load. The Tarm is a good choice as are some others, Randy
 
I wouldn't hesitate on installing cast iron radiators,like any other heat emitter they can be sized to use lower temps.when I woke up this morning the outside temp was 22* F but it was comfortable 72* F inside.I should add that I also have an Tekmar controller with outdoor reset that controls my storage and it was circulating 112* water through my rads.In mild temps we have used as low as 80* water.

What ever heat emitters you chose to use,by sizing them to use lower temps will make your storage that much more useful.
 
what tekmar controller with outdoor reset are you using Jeff?
 
Tekmar injection pump control for weil mclain.

Pex outlet has been selling these on eBay very reasonable.I believe they are a discontinued item.probably could use any of Tekmar,s injection controllers in a similar fashion.or possibly a Tekmar 256 using on/off controls instead of variable speed ,just that this unit was less expensive.

I'm using it a bit unconventional instead of the variable speed function controlling a circulator it is controlling a 120VAC solenoid valve that supplies my heat loop.It's a bit noisy but my system it is in an out building and doesn't bother us.Time will tell if the solenoid holds up,so far we have used it for about 3 months with no ill effects.Also am not using primary secondary as suggested but NoFossil's Simple pressurized storage system.

I installed one of these controllers on my neighbor's gas boiler as a regular controller with out using the variable speed function,in this application it works similar to a Tekmar 256 but with the added benefit of having a boiler return sensor that will start his boiler when return temps drop to what ever level you program the system for in his case 140*.My neighbors are in their 70's and never turn the thermostat down at night,though they had to tun it back 3* because it felt too warm in their house,I explained to them since they were using lower temperature water in their fin tube the heat was more even therefore more comfortable with the lower thermostat setting.
 
Brad said:
Thanks Hydronics: I hadn't considered those but only because I didn't realize gassifier combinations exist. I'm constrained by height (~82 inches) and flue diameter (6 inches) but I'll definitely look into them.
Click to expand...

Anyone recommending wood/oil combinations more than likely have never owned or operated one. I operated one for ten years and found it to be worthless, inefficient and troublesome. Almost impossible to tune for the best efficiency on both. You will be much better off going with what the Tarm Sales Guy (Chris) recommended. Separate units! I feel the biggest advantage to using propane for back-up is the fact that it can sit in the tank for several years waiting for you to need it for emergency heat and not go bad on you the way oil does. Separate units are also more efficient and when the life ends for one unit or the other, you only need to replace one of them.
 
Very good point about the propane/oil comparison Fred.
 
[quote author="Brad" date="1291534266"]The cistern should be fairly easy to insulate because it basically a cement box in the basement. I could insulate on either the inside or the outside, I'll have to think about that!

Hi Brad,

Insulate inside the tank. I don't think concrete likes sustained temps over 140 °F. Maybe talk to Tom in Maine about liners. He knows the deal.

good luck,
Noah
 
Fred61 said:
Brad said:
Thanks Hydronics: I hadn't considered those but only because I didn't realize gassifier combinations exist. I'm constrained by height (~82 inches) and flue diameter (6 inches) but I'll definitely look into them.
Click to expand...

Anyone recommending wood/oil combinations more than likely have never owned or operated one. I operated one for ten years and found it to be worthless, inefficient and troublesome. Almost impossible to tune for the best efficiency on both. You will be much better off going with what the Tarm Sales Guy (Chris) recommended. Separate units! I feel the biggest advantage to using propane for back-up is the fact that it can sit in the tank for several years waiting for you to need it for emergency heat and not go bad on you the way oil does. Separate units are also more efficient and when the life ends for one unit or the other, you only need to replace one of them.
Click to expand...

It depends how much you intend to use the backup source, if the answer is 1 week/year while away then efficiency while burning oil is of little importance. If you have only 1 flue than this may be the deal breaker. Buying separate units will give best efficiency but will probably cost nearly twice as much. Will you you get the return on your investment?
 
Thanks for all the comments!

I only have the one flue so that is the deal breaker for oil. Newmac has a sidewall venting oil boiler but I'm hoping to vent through an old basement window and the oil vent is too large. Three inch PVC will be better I think.

In my conversation with the finance committee (my wife) this morning it looks like we may do the backup heat first and in a year or two add the wood. I hope this may allow us to get any issues worked out before adding the storage and complicating things. Does anyone have a Lochinvar Knight gas boiler? They do cost a bit more but look to be quite self contained, PexSupply has them for $3600.
 
We also only have 1 flue. We did not have the room to have seperate units but we def wanted at leat 2 sources for heat as we tend to visit family in the winter on weekends so nobody home to feel the boiler. If you have the room I would go with seperates!
I agree that efficiency is probably much less than optimal on the oil side of our Wood Gun but it fit the needs for us. As for the oil itself, we had about 200 gallons of oil left in the tank when we installed the boiler and added something to the oil(I cannot recall what it is but it was mentioned in here somewhere, I could look when I get home) to help preserve the oil and reduce the chances of nasties growing in it. We considered the Newmac but I could not find enough real world users to give me input on their product.

On a side note...I almost fell out of my chair when I learned what heatng oil is up to around here! Makes my payback time a lot less!
 
Brad said:
Thanks for all the comments!

I only have the one flue so that is the deal breaker for oil. Newmac has a sidewall venting oil boiler but I'm hoping to vent through an old basement window and the oil vent is too large. Three inch PVC will be better I think.

In my conversation with the finance committee (my wife) this morning it looks like we may do the backup heat first and in a year or two add the wood. I hope this may allow us to get any issues worked out before adding the storage and complicating things. Does anyone have a Lochinvar Knight gas boiler? They do cost a bit more but look to be quite self contained, PexSupply has them for $3600.
Click to expand...

We are going to put ours in that way, but with a shorter gap.

Your btu sq ft is about 50 which to me sounds about right, I am looking at 75 but I have tall ceilings and brick walls and am at 10,000ft.

Radiators, if you are using cast iron and old it is bit of a guessing game as to their output. New radiators of either type come with a btu output for size and a method of recalculating using cooler or warmer water, generally with a wood based system the lower the water temperature the better.

If the cistern is in the building you have the advantage of any heat loss going into the building. As the wood boiler will be a batch system, the bigger the unit the quicker you get your storage back up, so go with a bigger one if you can.

I am using propane back up, I do not have an oil option here. The Propane units are very small so that might be an advantage. And make sure the design allows the boiler to provide Hot Water outside of the heating season. So efficiency does matter to some extent.
 
The 180,000 is input. They claim 77% efficiency?

I do not see how it could be anything like that.

It is a batch system with no storage so some back of the envelope calculations suggest a burn could last 5 hours. Which must reduce the efficiency.
 
It is certified under CSA B-415.1 which is the 'EPA' standard in Canada. The beauty of this standard is that it calculates the emissions in grams per megajoule of heat output. So not only does it have to burn clean, but to have an excellent rating, you have to maximise the output in the ducts. That furnace is very efficient. The firebox is about 4.5 cu ft...lots of capacity.
 
EPA Standards are a bit of a joke, I would hope Canada has something not designed by OWB manufacturers.

What is the design feature that gets 80% efficiency? I could not see it on the web site?
 
We'd thought about the Max Caddy but the cellar ceiling height is too low to make it work (got to keep it off the ground like 6" for the spring flood and still have space for a decent plenum). The firebox in it is only a bit larger than the Caddy - I'm a little concerned I would have more of the same. And of course, I still need more ducts to the second floor.

Como: how high are your ceilings? Wasn't sure if I mentioned that our's are 9.5 - 10ft. I was actually working with 36 BTU/sqft on the first floor with 45 on the second. That gets me really close to 120K BTU total once I get a rad in the cellar. There are some tables that you can use for calculating the output from cast iron rads - Weil-McLain has it in a nice book, page ten: http://www.weil-mclain.com/en/multi.../other-downloads/boiler_replacement_guide.pdf.

Thanks for all this - it's great!
 
Status
Not open for further replies.

Similar threads

K
Help! Need replacement system for my Newmac oil/wood combination furnace
Replies
3
Views
2K
The Boiler Room - Wood Boilers and Furnaces
brenndatomu
brenndatomu
P
Dodging a bullet with my heating system
Replies
0
Views
955
The Boiler Room - Wood Boilers and Furnaces
peakbagger
P
N
Conversion from oil
Replies
8
Views
854
The Boiler Room - Wood Boilers and Furnaces
brenndatomu
brenndatomu
DerrickH
Wood Furnace ducted into with Heat Pump and unsure of dampers
Replies
9
Views
1K
The Boiler Room - Wood Boilers and Furnaces
brenndatomu
brenndatomu
P
Looking for recommendations indoor wood boiler
Replies
10
Views
3K
The Boiler Room - Wood Boilers and Furnaces
Woodfarmer1
W
Top Bottom
Back