Time for a complete system overhaul -- Looking for input.

[MikeK]

I picked up the unit. $ 2700 for the boiler, expansion tanks and miscellaneous piping components. The 2x500 LP storage tanks were left behind because they won't fit through my basement door and I don't have enough ceiling height for them.

I'll be taking to over to Dean @ Smokelessheat.com and see what thinks of the condition.

Now to begin planning how the flue and storage, then start laying out a piping plan. I would like to be operational for the next heating season.

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Nice buy! I am not a boiler guy, but since the propane tanks won't fit, would @ Tom in Maine's non-pressurized storage be an option? http://www.americansolartechnics.com/

 

[mtnsideman]

Leaning towards pressurized storage. My doorway is 36in wide and my height restriction is 87 to the sub floor, 78in to the bottom of the floor joist.

A 30in dia. x 72in 200gal vertical pressure tanks will fit my space but the challenge is they are $1700+ each. The other option I'm considering is getting used 120 gallon propane tanks and cutting/welding two of them together to make them 200 gallon verticals.

120 gallon horizontal propane tanks are only 24in dia.
250 gallon horizontal propane tanks are to long to stand vertical in my space and would require to be cut down to fit.

I plan to spray foam the tanks so 30in tanks with foam should fit through my door.

3 of these would put me at 600 gallons of storage, plenty to get started with. I might add more in the future depending on how things go.

 

[salecker]

Check your local scrap yard to see what they might have.
Air compressor tanks,farm use tanks for ammonia, ect

 

[Woodman1]

Do you have an outbuilding you could put them in? Ideal would be inside, but might not always be practical.

 

[mtnsideman]

System is going into the basement for now. In the future I would like to move it to detached garage that isn't built yet and trench the hot water across the driveway to the house.

 

[maple1]

Pretty sure my 330 gallon tanks are also 30in. diameter. You don't have to go vertical, mine are horizontal, stacked.

 

[mtnsideman]

How critical is it to get the flow to stabilize before entering the tank to reduce mixing?

The piping for vertical tanks makes sense to me. How much straight pipe should be used before entering the tank?

For horizontal storage, should the flow enter vertically? Or does none of this matter because the % improvement not make it worth the effort? Just build something and roll with it?

In my head, I was planning for 3 vertical 200gal tanks in series. 30in diameter tanks with spray foam should get me through my door. 120gallon vertical propane tanks cut in half and welded together to clear me ceiling is the cheapest option that I have identified. The larger 30in dia propane tanks are too tall to stand vertically and I haven't convinced myself to go horizontal yet....

Where can I read up on the recommended sizes for the system piping?

 

[hobbyheater]

How critical is it to get the flow to stabilize before entering the tank to reduce mixing?

The piping for vertical tanks makes sense to me. How much straight pipe should be used before entering the tank?

For horizontal storage, should the flow enter vertically? Or does none of this matter because the % improvement not make it worth the effort? Just build something and roll with it?

In my head, I was planning for 3 vertical 200gal tanks in series. 30in diameter tanks with spray foam should get me through my door. 120gallon vertical propane tanks cut in half and welded together to clear me ceiling is the cheapest option that I have identified. The larger 30in dia propane tanks are too tall to stand vertically and I haven't convinced myself to go horizontal yet....

Where can I read up on the recommended sizes for the system piping?

Could you foam the tanks once they are in place with the plumbing done ,would make it a lot easier to spot and fix leaks .

 

[mtnsideman]

Could you foam the tanks once they are in place with the plumbing done ,would make it a lot easier to spot and fix leaks .

Yes. Strategic use of pipe unions could make it easier to disassemble to move the tanks to the middle of the room for foaming post leak test.

 

[mtnsideman]

I'm considering upgrading to a hybrid DHW heater to get away from oil boiler DHW coil. This would also help dehumidify my basement. Anyone have opinions on these units?

Also what is the go to equipment for pump and zone controls? I'm working on my preliminary piping plan and hope to share it soon for review.

I believe that my house has plenty fintube baseboard so it is likely that I can operate them at lower temps and still deliver the BTU's needed to properly heat. This will get even better as I work to get the house tightened up.

 

[mtnsideman]

Here are some piping plans that I could use some second opinions on. This layout is based on the diagram on page 209 of the (broken link removed). I also reference diagrams on pg. 170, and 172.

 

[hobbyheater]

I believe that my house has plenty fintube baseboard so it is likely that I can operate them at lower temps and still deliver the BTU's needed to properly heat.

Fintube needs 150 degree water.

 

[mtnsideman]

Two years later, I'm finally making the push towards getting this system in place. Time flies by when you have little kids and way too many projects on the to-do list. I purchased LP tanks to create 1,000 gallons of storage for $800. They are brand new but had pin holes in known locations that needed to be welded, and are no longer fit for propane service. I've decided to install the system in my garage, where I have room for this size of storage.

The wood boiler will be plumbed with primary/secondary loops to make use of the pumps that I have and avoid purchasing a loading unit (which I've found difficult to locate). A VDT pump will inject cold from storage to maintain the ideal boiler temperature. There will be a loop to provide heat from storage to my main load loop. This would be in parallel with my oil boiler loop. Reference the attached images. This is what my system is planning to mimic.

I'm seeking assistance with setting up the control system. I want the Wood boiler/storage to be my primary heating. The oil boiler will be my secondary heat and DHW supply for now. What do I need to purchase to control this properly?

 

[salecker]

On my system all the wood boiler does is feed storage.
I have a pipe from the feed to storage that a pump circulates through my plate HX. On the same pipe i have a 2 position aquastat. Once the temp coming from storage drops to around 100 F the aquastat switches from the circ that feed the plate HX, to powering my back up oil boiler
Been working flawlessly for 16 years

 

[mtnsideman]

Making progress.

 

[mtnsideman]

One tank is up. The second tank will go up soon when I finish the expansion plumbing and the loop plumbing that ties into the oil boiler.

 

[mtnsideman]

Second tank is up. Expansion tanks are hiding under the steps to the left. Qty 6 SX-40V. That should give me enough expansion capacity.

 

[mtnsideman]

Made my first few burns over the weekend. Pretty happy with it so far. I need to still figure out a few control tweaks so that it will automatically switch to oil heat. I'll tidy up the wiring and insulate the pipes soon.

A full burn seems to elevate the storage temperature by +40 degrees. Nearing the end of a burn, my tanks are 170+ degrees on the top and bottom sensors. My oil system does not like letting the storage temperature drop below the low limit switch (~135degrees). Since I'm using the oil boiler circuit with an aquastat to control the circulator to send hot water to the oil boiler, it cuts off the circulator when called for heat. So it gets stuck in a control loop trying to fire the boiler, but my storage tank temperature is still warm enough to give control back to the oil burner.

So, do I raise my storage output aquastat temperature above the low limit on the oil boiler? Or do I add a relay to power my house circulator when pulling heat from storage and set my storage aquastat to a lower temperature?

I thought I would have more buffer capability, but it's trending that I should not burn a full load unless my tanks are under 140 ° top and bottom, which puts me on the threshold of the oil system taking control. Are partial batch burns practical?

 

[salecker]

On my system with storage i have the wood boiler feeding storage as it's only job.
From the feed going to storage i have a tee that goes to my heat ex-changer as i run water in the wood boiler and storage, on that line i have a two way aquastat. It is set to fire the oil boiler when it see's 100F.When that happens the pump on the line going to the heat ex changer shuts off and the oil boiler fires up. The oil boiler is only controlled by it's high limit switch when it is firing.
The next fire in the wood boiler shuts off the oil boiler once it see's water higher than 110F
If i go away for a while i shut off on of the 4 valves on my heat ex changer to stop the oil from heating storage with ghost flows.
On year 16ish working flawlessly so far

 

[hyfire]

Can you draw this all out on paper to understand it more? Also how are you preventing the wood boiler from getting return temps not less than 140F?

 

[salecker]

Can you draw this all out on paper to understand it more? Also how are you preventing the wood boiler from getting return temps not less than 140F?

I am running a near boiler pump that Econoburn recommends for return temp control.
it connects the top and bottom of the boiler and circulates till the temps are warm enough then switches to the storage supply pump. They jockey back and forth as the temps go up.
I can try to sketch it out

 

[salecker]

Made my first few burns over the weekend. Pretty happy with it so far. I need to still figure out a few control tweaks so that it will automatically switch to oil heat. I'll tidy up the wiring and insulate the pipes soon.

A full burn seems to elevate the storage temperature by +40 degrees. Nearing the end of a burn, my tanks are 170+ degrees on the top and bottom sensors. My oil system does not like letting the storage temperature drop below the low limit switch (~135degrees). Since I'm using the oil boiler circuit with an aquastat to control the circulator to send hot water to the oil boiler, it cuts off the circulator when called for heat. So it gets stuck in a control loop trying to fire the boiler, but my storage tank temperature is still warm enough to give control back to the oil burner.

So, do I raise my storage output aquastat temperature above the low limit on the oil boiler? Or do I add a relay to power my house circulator when pulling heat from storage and set my storage aquastat to a lower temperature?

I thought I would have more buffer capability, but it's trending that I should not burn a full load unless my tanks are under 140 ° top and bottom, which puts me on the threshold of the oil system taking control. Are partial batch burns practical?

View attachment 342550

I would reverse one set of outlets
on the tanks to try and make the flows even. I have a double check valve on my return that is supposed to help according to the guy who designed my plumbing.

 

[mtnsideman]

Can you draw this all out on paper to understand it more? Also how are you preventing the wood boiler from getting return temps not less than 140F?

The Vedolux 37 controls the circulator pumps. The primary pump turns on and pumps the water in a circle. The secondary pump is a variable output and turns on when the boiler output aquastat reaches the set point temperatures. The secondary pump injects cold water into the primary loop to try to maintain a delta_T across the boiler inlet and outlet. If my storage tanks are cool, this pump runs very slowly or turns off if the boiler output temp drops too low. It will run full speed if the tanks are hot.

My oil boiler maintains a low limit to supply my DHW needs. When it calls for heat, it sends power to the burner, which I've redirected to an aquastat. If my storage tanks are hot, a circulator will pump hot storage water to the oil boiler. If the storage tanks are cold, the power is redirected to the burner to heat the oil boiler.

This means that I need to maintain storage temperatures above my oil boiler's low limit to utilize the wood heat appropriately.

I've also talked with Dean at Smokelessheat, and he mentioned that I should be able to drive my storage temps higher to store more heat and utilize the capacity better. As I'm burning more frequently now with the colder weather, I've been driving my storage temps higher. I've seen 60deg delta (195 Top, 135 bottom) between the tank temps when the wood boiler pumps are off. As the storage heat is being used, the stratification diminishes as the circulator pump attempts to deliver enough BTUs to the oil boiler to maintain the low limit setpoint.

The good news is that my wood consumption is trending towards a 50% reduction, the house temperatures are stabilized, and I've increased the thermostat to 70 degrees. The old insert unit I was using overheated the room it was in and wasted a significant heat up the chimney.

 

[hyfire]

Interesting but are you able to make sure each tank is getting equal flow? Only way i see is using a flow meter, like the caleffi quicksetter series balancing valve.

 

[mtnsideman]

I don't have flow meters. And don't plan on installing any. The tanks are piped in parallel and my feed loop supply is out the right side and the return comes into the left. So the assumption is that they are balanced. I do have thermal wells in each tank so I could measure both tanks independently for temperature high and low. But I would be surprised if there's a significant discrepancy between the tank temperatures.