I just purchased a used 6048, and have a couple of questions regarding both the machine and the piping used for OWBs. I can't find a btu/hour rating for the 6048. I know they used to list this years ago, but they seem to be keeping it a secret these days. Does anybody know how many btu's I can expect to draw off of this size boiler an hour?
Second is the Pex tubing. Central offers their own ThermoPex tubing in 1" and 1.25" diameters, and PexFlex offers dual insulated tubing in a variety of sizes. Any advice and where to buy either would be appreciated. Thanks. (I'm sure I'll have more questions later)
I just installed the same set-up this fall. Find your local dealer, he should have the Thermopex in stock. It is expensive but it is definitely worth it. I used 1" on mine with a 145,000 btu heat exchanger. Our house is a little over 2500 sq.ft. It is insulated pretty decent and I have no trouble keeping it 70 degrees.
The question is not what diameter pex you need, the question is to estimate the amount of energy you need to deliver to your house. First, what is the distance going to be from the house to the OWB? the longer the distance, the larger diameter Pex you should use. My run is long, about 300', and I used 1.25". I have a large house and need the ability to move the heat quickly.
You should use insulated pex tubing. Uninsulated piping in the ground could cost you a few cords of wasted heat every year. Basically the more the pex is insulated the less heat is wasted.
My 5648 = maximum Btu...500,000 as someone else said find a dealer to get the thermo pex it is pricy but worth the money it is $14 PLUS A FOOT
we put the thermo pex on top of the ground for my dad 4years ago it was only going to be temp but you know how that goes the snow never melts off it so why do the digging :D :D
For now, the boiler will be about 30 feet from my garage, but may get moved later if I have the money for more pipe. The two pipes I mentioned are both two pipes inside a larger pipe with insulation around them.
I don't know the exact requirements of my house, but I don't want to make the mistake of running too small of a line. A friend did that with his 6048. It came with a piece of 3/4" line and he can't move enough to keep his wind tunnel log cabin warm. I also need to heat the two car garage.
What kind of stove pipe does a Central use? It looks like standard 8" insulated pipe would work, which is handy, as I have a T and 3 sections of pipe that I won't need in the garage if I install an outside boiler.
And another question. I am going to use a heat exchanger in my basement to hook the OWB to the oil boiler. I plan on running just water in the OWB, no anti-freeze. Is this typical, and are there additives other than AF to put in the OWB water?
There is a corrosion inhibitor that you need to use in the water in the boiler.
That's what I thought. Is that from Central only? I think I might be going to the Central dealer in the next week or so.
I did not install mine. This is how the back of my Heatmor looks. I could have 3 zones on mine. I think I have the 1 inch lines,inside is ¾.
(https://forestryforum.com/gallery/albums/userpics/10436/thecfarmoutdoorfurn1%7E1.jpg)
There are a view more pictures in my gallery,outdoor furnace is the album name.
Finally got a chance to go and get my boiler. Now I just need to figure out how I'm going to get it off the truck. :D
Does anybody know of a chart that lists how many btus per hour a given size pipe can move at a specified gpm and temperature?
(https://forestryforum.com/gallery/albums/userpics/14240/newbiler.jpg)
Dave
Don't assume the 8" pipes you have will fit the CB. The ones I had, the ID was the same but the OD was 1/4" smaller. I had to do some modifications to make them work.
UN
Taco has flow charts. They are used to size the pump to deliver the required gpm needed based on pipe size and head {friction loss}. A 11/4" pipe with a flow of 16 gpm will be 160,000 btu's, a 11/2" pipe at 24gpm is 240,000 btu's. Head is figured on overall length of pipe and its friction loss , it has nothing to do with height.
I got my heat exchanger today. It's a little big, but that's better than a little too small. Best of all, it's free. :) Going to start getting my fittings list together tomorrow, then I'm going to get all my parts and pipe and start installing.
Quote from: Dave Shepard on January 28, 2014, 08:15:02 PM
I got my heat exchanger today. It's a little big, but that's better than a little too small. Best of all, it's free. :) Going to start getting my fittings list together tomorrow, then I'm going to get all my parts and pipe and start installing.
now comes the hard part well not so much these days when I did mine they had no easy fittings these shark bites are the best they were made for dummys like me :D :D
Hurry and fire that thing up, Dave. There's still plenty of winter left to save some of that oil money. splitwood_smiley
So, next question. I'm buying 1" ThermoPEX from the Central dealer to go from the boiler to the heat exchanger. The fittings on the boiler are all 3/4" pipe thread, but the previous installation was also 1" PEX. Is this momentary restriction ok? The manual doesn't mention this specifically, but they do have two different parts lists, one for 3/4" fittings and one for 1 1/4" fittings, and they only mention using 1" T PEX, or 1 1/4" T PEX pipe. I know that 1" PEX is actually more like 7/8" ID, so I"m thinking the momentary restriction is going to be ok.
Here, you can see the original installation with a piece of 1" PEX pipe on the return.
(https://forestryforum.com/gallery/albums/userpics/14240/20131226_111617.jpg)
If you think you need all the btu's that boiler will make then I would increase those 3/4" pipes to 1" or 11/4". I look at this as a professional and it would be wrong for me to undersize the piping and make it so you can not get all the heat from your boiler. If the tappings are 3/4" in the boiler then leave the 3/4 connections.
Dave,
I think from my physics class many years ago Bernuli's principal I think rules that a very short restriction will not affect flow as speed thru the restriction increases and volume is maintained.
Perhaps a hydraulic engineer will chime in and either confirm this or tell me I am full of it.
DoctorB How much heat loss do you have with your long run?
My initial installation was 125 feet and I lost 9 degrees.
This was with the insulated pipe furnished by the Taylor furmace folks.
It was not buried very deep and the snow melted where the line was.
I only used this system for 3 winters as I kept warm carrying wood to the Taylor not to mention putting the years wood up.
Pete
The Central has 3/4" and 1 1/4" tappings. These fittings are in the 3/4" tappings.
Pete, that was my recollection as well, although I have no recollection of Bernuli. :D
Dave you are correct 3/4" pipe thread = 1" pex I have 150' of 1" thero pex from the stove to the house the water is being pushed by a taco 009 pump once in the house I built a manifold out of 3/4" tees and ball valves to move the water three different ways (my house was 1000 sq' added on 1500 sq' plus 32x38 garage) so I have 3 furnaces and 2 water heaters the 1" pex heats it all 73 in the house 75 in the garage plus all the hot water you want
One of the mistakes a lot of people make is they run everything inside the house in series. So imagine you invest in 1 1/4" pex because you want a high rate of flow and the high rate of flow allows you to pull more BTUs from the boiler. Then you run your pex runs to the heat exchanger in your furnace where it gets reduced to most likely below 3/4". You've just killed most of the benefit from running the 1 1/4 pex. You did get some benefit with less head on the system but your rate of flow isn't what you would expect.
What I did was ran 1 1/4" from my boiler to my house. It transitions to 1 1/4" copper in the house and it makes a loop and goes back out to the boiler. So my entire loop is 1 1/4" with only four 90 degree fittings to form the loop in the house. I've lost virtually no rate of flow at all. Then on one side of that 1 1/4" loop I have a number of closely spaced Tees (basically a 1 1/4" manifold) and I have a separate loop running to my furnace and another loop running to my garage and another loop running to a HX for my hot water. Each of those loops has its own pump.
So when the heat for the furnace kicks on it pulls water off that 1 1/4" loop and pumps it through 1" pex to my furnace HX and then dumps it back into the 1 1/4" loop. That means my garage heater can also kick on and it has full access to that 1 1/4" loop at the same time as my house furnace.
I also installed my heat exchanger in the furnace upside down. The hot water enters the hx at the top and the cooler water comes out the bottom. That's backwards from the recommended method. But think about it....if your hot water enters the bottom of the HX that's where the cold return air first touches the hx and begin's to warm. That air begins to warm and when it exits it the top of the HX its being exposed to cooler temperatures because your outlet water is always cooler than the inlet water. In my system, the cooler temps are at the bottom of the hx and the air begins to warm and just as it leaves the HX its exposed to the hottest temperature because that's the inlet for my hot water. So you get more efficiency out of the HX by installing it the way I did. The reason they recommend the inlet on the bottom is to eliminate air pockets in the HX. Not because its more efficient.
None of my stuff is in series.
The other thing I did was use grundfos pumps instead of Taco. The grundfos pumps have 3 speed adjustments for fine tuning your system. My main pump is in the house, not at the boiler. Its installed near the basement floor so it takes advantage of the water dropping towards the pump to improve efficiency. If I have a pump go out, I can change it in the warmth of my home rather than standing in the cold out by the boiler. I can also add water to the system from in the house.
MNBobcat That sounds like a very well designed system.
I won't be loosing much at my heat exchanger, it has 2" ports on it. :D Due to the need for a little simplicity, and economy, I will be running the return from the boiler through a Modine in my garage. It also is way oversized, and will have constant water circulation in the winter, and the fan will be on a thermostat.
Holmes,
Thanks. I had a few challenges. The boiler loop ended up being about 550 feet round trip. I was really concerned about flow rate at that distance. But I wanted the boiler located between my house and the pole building as I ran heat to both.
The other is my house is 7,000 square feet. I was worried about getting enough btus to heat it. So far the system has worked well but when its -20F out like it has been much of this winter, I've found its best not to turn the thermostat down at night. Seems it can hold the temperature easier than bring it up. One problem is when they built the house they didn't size the main heat plenum big enough. At some point I'm going to rip it out and up-size it.
It takes a lot of btu's to replace the ones you did not put into the house all night long . Leaving the t stat set a normal temp is the better thing to do.
Dave How big is the Modine? Sometimes $implicity works out well. :)
The core must be 20" square, maybe bigger. Garage is a typical two car. Should be big enough. :D
My heat exchanger is used, and huge, but free, and has 2" pipe fittings. I thought I was going to have to buy 2" to 1" reducing bushing and then use 90° pex fittings to pipe it where it needs to go. I was digging around in the shed and found four 2" to 1" elbows today. That's four fittings I don't need to buy. 8)
Like I said, the exchanger is huge, but free. 8) Oh, and this was the smaller plate exchanger I was offered. :D
(https://forestryforum.com/gallery/albums/userpics/14240/20140201_143204.jpg)
Dave,
When you install that its a good idea to install the valves with a hose bib so that you can put them in bypass mode and pump a cleaner through that plate exchanger to clean it from time to time.
Also, remember to have some kind of union connection. For ease of maintenance or replacement in the future.
That heat exchanger will definately be able to keep up with the boiler, even if running snowmelt!!! :o
So I finally got my new door today. Well, I got everything but the door. ::) All the tin, damper insulation and a couple of strangely shaped pieces of plate steel. But no cast iron door. >:( Of course it was too late to call and see what the story was. You would think that having the model number, date of manufacture and serial number would get you the right parts.
Still no door. I guess it's a good thing this wasn't my only source of heat. I did, however, burn about $3,000 worth of fuel oil while I was waiting for it. Might have it next month was the answer I got on Monday. ::)
Dave, did you buy it knowing it didn't have a door? Or what happened to the door?
Quote from: MNBobcat on January 31, 2014, 11:01:02 PM
I also installed my heat exchanger in the furnace upside down. The hot water enters the hx at the top and the cooler water comes out the bottom. That's backwards from the recommended method. But think about it....if your hot water enters the bottom of the HX that's where the cold return air first touches the hx and begin's to warm. That air begins to warm and when it exits it the top of the HX its being exposed to cooler temperatures because your outlet water is always cooler than the inlet water. In my system, the cooler temps are at the bottom of the hx and the air begins to warm and just as it leaves the HX its exposed to the hottest temperature because that's the inlet for my hot water. So you get more efficiency out of the HX by installing it the way I did. The reason they recommend the inlet on the bottom is to eliminate air pockets in the HX. Not because its more efficient.
In order to get maximum efficiency from a water to air heat exchanger like you have, you must put the coldest air up against the highest temperature water. In other words you want to have the maximum temperature difference from the incoming water side of the exchanger to the incoming air side. That requires the water inlet to be on the incoming air side of the exchanger or down in an upflow furnace.
Plus there is nothing that will kill the efficiency of that heat exchanger more than having air trapped on the water side of the exchanger.
So I am sorry, but putting that exchanger in up side down will hurt rather than help efficiency. You can relieve some of the air trapped problem by adding an air eliminator at the top of that exchanger but sometimes those air eliminators do not work well all the time.
Also the size of the water line has more to do with the maximum head capacity of those pumps than it does with the heat transfer ability of the system. So your line size will depend on length of line, number of elbows, restrictions in the system, height of the heat exchanger above the boiler, etc. The BTU's you need is determined more by the heat exchangers you put in line.
So you always size your line by the amount of resistance called head or back pressure in your system to avoid overloading the pump capacity. Then you size your heat exchangers for the amount of BTU's you need.
The other part of my door came in last week. They want another $104 shipping. I was supposed to get one complete door, shipped, for $500 in February. Now, I have an erector set and double shipping charges. ::) I think I'm up to about $4,000 worth of oil burned waiting for the door. :-\
I finally got the last parts to my door. Central Boiler parts diagrams suck! I managed to get all the pieces of the erector set together, despite the paperwork. Just waiting on running the power to try it out. As I mentioned before, I was told that one complete, assembled door was $500 shipped to the dealer, that they were in stock, and would be in in one week. I got all of the crucial parts, eventually, but did not have any of the hardware, and some of the parts were not the same as in the diagrams that came with the new parts. ::)
(https://forestryforum.com/gallery/albums/userpics/14240/20140817_163016.jpg)
We have lift off! Well, hopefully no lift off, but we have smoke. :D I had to guess at the location of the draft door solenoid, but it looks like I got it pretty close, as the draft door opens the allotted 1". I've got a small fire going in it now, and will let it warm up all afternoon and see if it cycles properly.
(https://forestryforum.com/gallery/albums/userpics/14240/20140818_145051.jpg)
Temp came up to 185° and the door snapped shut. 8) I'm amazed at how well insulated the boiler is. I don't have a load on it right now, so the fire went out over night, but I started it again this morning to continue the testing. I shut the boiler off this afternoon, and it was at 187°, and a few minutes ago it hadn't lost any temp at all. I realize that my temp differential isn't as great now, only about 110°, but I kind of expected it to drop faster.
On another positive note, I talked to a friend today that has the same boiler and quizzed him on burning pine slabs. He said that they are his favorite fuel, period. His fire has been burning continuously for over a year, and he has less than 4" of ash in the bottom, and he never takes any out. In the summer he stuffs the boiler at 10 PM, and in the winter he does 10 PM, and 7 AM. That makes me happy, as I now know where this pile is going this winter:
(https://forestryforum.com/gallery/albums/userpics/14240/20140620_173151.jpg)
It's going to feel good watching the fuel oil truck driving by your place this winter.
Did you get your lines buried yet Dave?
No, that is the next step. I have the Pex pipe already. I have to poke a couple of holes in the foundation of my garage. Going to work my way from the boiler to the oil furnace in the basement of the house. I have the heat exchanger and a big hanging Modine for the garage. Biggest pain will be breaking into the oil furnace to add another circulator. Since the end of Jan, I've burned about $4,000 in oil, and that wasn't keeping the garage warm, or the house too toasty, either. It takes about eight gallons a week right now for domestic hot water.
Ouch... about $100.00 a month for dhw?
Better get yourself a sidearm built for your hot water needs. Or is that what that plate exchanger you picked up is getting used for?
There is going to be a circulator running from the oil side to the exchanger all the time. This will keep the oil burner hot, and I will use my current heating zones in the house. The oil will not run unless there is a breakdown with the wood boiler. I plan on running the OWB all year.
You won't get many ashes from the pine slabs. I have burned pine for just about 2 years through the winter months.
I have 6' of insulated chimney on my boiler now. I was wondering if adding anymore would be beneficial on a 6048? It's in a open spot now, so no need to go any higher, unless it will help the draft.
I doubt the higher stack would help out my Heatmor. Probably the same with yours,forced draft by a fan?
No, the Classic boilers are natural draft. I asked the dealer about a fan, and he said if it was supposed to have one, it would. I have also read many accounts of people building their own fans, and every one of them took it off. Apparently, a fan is only necessary if you burn nasty, wet, rotten garbage. I have nice dry slabs. :)
No fan does change my theory. As long as it will smother the fire out,with no boil overs, is all that matters.
That good you've got dry slabs stockpiled, Dave. It wastes a lot of btu's to burn wet wood.
I've been working away at my installation. It's almost all scrounging, but I've done pretty well so far. :D I've got one circulator and most of my fittings. Going to have to break down and buy another 009 and some more PEX for in the basement. Picked up about 80' of PEX with a bunch of the fittings tonight. My plumber friend is coming this week to do whatever he deems necessary to attach my PEX and circulator to my oil burner. I've got about 8 days of firewood for the wood stove in the house left in the pile, so the race is on. :D
I sure hope you are buying enough of the underground insulated pex, the kind with the two insulated lines inside. That underground pex from Central Boiler is expensive but worth every penny of the cost. I had mine laying on top of the ground for one winter and it never melted the snow off the top of the bare line.
I bought the good stuff for outside, Fostapex for the inside.
I have the exact set up that you are using with the heat exchanger and the circulator in the oil boiler. It works great but I had very bad luck with short circulator life in the beginning. CB recommends the 009's but I found that just running the heat exchanger loop on the low pressure side they were cavatating to death. I was getting about 3 months from each. I switched to just 007's which are much cheaper and have 3 years on them with no loss in performance.
There is no elevation difference between the circulator and the exchanger which could affect the installation.
I do revert back to using oil during the summer months for domestic hot water.
Good luck with getting the system fired up soon.
Wayne
Where is your circulator mounted? Mine is right on the boiler.
Yup, the circulator is on the OWB with the heat exchanger located about 100 ft away in the basement. I have 1" pex line to the heat exchanger. Could be just something peculiar to my installation - your mileage may vary.
I've got the heat exchanger mounted and the wood boiler side of the plumbing done and circulating. My plumber friend is coming in the morning to break into the oil boiler and put the circulator on there and any other valves and fitting needed. I've got the parts to put a make up line from the domestic water to the wood boiler side of the exchanger. You can see the valve on the bottom right fitting. My friend is bringing a proper backflow preventer to put on the other end of the 1/2" PEX that I'm going to run for that. My boiler isn't far from my hatchway, and I was just going to keep a hose coiled up in the basement for the make up water, but a friend with an OWB suggested that that (Tom) might not really be all that appealing at 2:00 AM with two feet of snow on top of the hatch and it's -10 F. :D So, now I'll be able to just open the valve and top it off if needed. I've got to say that wrestling that insulated PEX pipe into the foundation and getting it just where you want it is a five person job. Too bad I only had myself to do it tonight. ::) :D OH, and don't worry about the bent handle on that valve, I'm going to get a longer pipe nipple and straighten the handle. I've got over a half a ton of galvi pipe fittings, but no short nipples. :-\
(https://forestryforum.com/gallery/albums/userpics/14240/20141113_170952.jpg)
Quote from: Dave Shepard on November 09, 2014, 06:03:05 PM
I've been working away at my installation. It's almost all scrounging, but I've done pretty well so far. :D I've got one circulator and most of my fittings. Going to have to break down and buy another 009 and some more PEX for in the basement. Picked up about 80' of PEX with a bunch of the fittings tonight. My plumber friend is coming this week to do whatever he deems necessary to attach my PEX and circulator to my oil burner. I've got about 8 days of firewood for the wood stove in the house left in the pile, so the race is on. :D
Well, I won, with three days worth of inside wood to spare. 8) I had a bucket full of inside wood and pulled up to the OWB and just tossed it in. Didn't have to go up the steps to the house, or leave a trail of dirt across the living room. ;D That was three days of heat done in two minutes. :)
I've got most of my heating project wrapped up. Just some insulating details and a thermostat for the Modine I put in today. I stuffed the boiler about 8:30 this morning, and this is what I came home to twelve hours later:
(https://forestryforum.com/gallery/albums/userpics/14240/20141116_203913.jpg)
8) 8) 8) 8) 8)
About right Pete. Frictional losses are a function of length so double the length double the restriction. Get into bigger pipe for long runs. Only problem will then be heat loss. You will need good insulated pipe as bigger the pipe bigger the loss. I have used twin pipe preinsulated Upnor which is very good but not sure what you have there.
I'm using Central Boilers twin PEX insulated pipe. It's about $14 a foot for 1". It seem to be very good.
I had to pry the shanty cap off of my stack a little bit ago. It had gotten smashed down a little in storage, and had gotten plugged with creosote. Not fun balancing on top of the boiler trying to pry that off in the dark, but now things are doing much better.
Quote from: Dave Shepard on October 08, 2014, 08:29:47 PM
I have 6' of insulated chimney on my boiler now. I was wondering if adding anymore would be beneficial on a 6048? It's in a open spot now, so no need to go any higher, unless it will help the draft.
Dave - Just now found this thread. I have the CB-648 and had it up for about 45 years now. Installation is documented here: https://forestryforum.com/board/index.php/topic,33912.0.html (https://forestryforum.com/board/index.php/topic,33912.0.html)
I have 4 chimney sections on mine. It gets the smoke up away from the house. Otherwise we had smoke coming in when the doors to the house were opened, and it's 80 feet from the house.
It looks like you are pretty well into it now, but let me know if you have any questions.
I have no further need for draft at this time. 6' is plenty. :D Anyone who thinks an OWB needs a blower, and there are many, needs to reassess the quality and dryness of their wood. ;)
I have a heatmor with a blower. There is no natural draft. I can and have burned cedar that has been leaned up against another trees for years. No limbs on it to even cut off.It will smother that bone dry cedar between cyles AND no boil overs either. ;) I kinda doubt your OWB will do that. That is why I like a OWB with no draft. But that is why I went with the Heatmor too. I did have ALOT of dead standing wood to get rid of. After about 7 years,I don't have much dead wood to cut.
What are you saying mine won't do? I am burning old pine boards and pine slabs. It smothers it right down so you don't think it still burning, just a big pile of dark charcoal, but when the demand comes, it lights right up. I haven't had any boil overs, but I am having a "boiling" issue. See my new thread. I think it's because I've got the temp set too high, and I'm not pulling the heat away fast enough.
Sorry,Dave I was wrong. Does just like mine than. Just with no blower. ;D
The CB units don't need a blower. They get plenty hot enough without forced air.
The 007 is proving to be too small at -10°. My baseboards ran pretty much continuously yesterday at 15° as far as I can tell. It maintained 72° during the day, but with -10° and windy, it was 63° in the house this morning. We don't often get much below zero, so I'm not sure how much of a hurry I am to swap pumps, but I will probably do something at some point. I don't know if I'll just put an 009 on the oil furnace to replace the 007, or if I'll move the 009 from the wood boiler inside, and put an 011 outside. The boiler had no problem making the heat, just couldn't get it inside fast enough.
That's too bad Dave. I don't know if I mentioned on this tread,I run 2 007 and at -12 in the night,the house is warm. But I do have forced hot air,up stairs,if that matters?? No baseboard. 63° is not good inside at this time of year. Good luck to ya.
It'll take more than 63° to upset me. If I was running the woodstove, after last night, it would have been 43°. :D With broken baseboards. >:( It's been 10° pretty much all day, and it was up to about 70° just now, so I think I'll be good to go until the next cold snap. My plumber thinks swapping the 007 on the oil furnace is all that I need to do, but I might still put an 011 outside and an 009 in the basement. We decided that having too much heat available wasn't going to be a problem. :)
I've got about a weeks worth of pine logs for the wood boiler, and then my weekends will be free again. Oil is cheaper than log length, and I don't have to cut, split and feed the oil. :D The way I'm set up, when the oil boiler temp drops below what the wood boiler can maintain, either due to insufficient heat supply (see previous posts above), or the fire goes out, the oil furnace will kick on. I had to have some work done on my oil burner to get it working today, but it looks like I'm all set to phase out the OWB, for the most part. I do have some sawing to do, so I'll burn the slabs as they are made, but that's it. I don't even know if there is any burnable log length around right now, and I estimate it will take $700 or more worth of log length, and about $500 in fuel oil, less if I get the 30% increase in efficiency I was told I'd get if I hoed the truckload of soot out of my oil furnace. :D
My boiler is just about to start it's fourth heating season and the circulator on the wood side conked out. It was a used 009 that ran about 26,000 hours non stop. Had a few spare circulators of unknown quality, and found one that worked. :D I don't know what size if is, but the door on the boiler won't close now. Probably an 011. Going to have to hit my plumber up for some more spares. That's getting harder now that he's pretending to be retired. ;D
The heat exchanger is pretty amazing. 207° water going in, outlet doesn't even feel warm. House is down to probably 60° water temp, so its really taking the heat.
Quote from: Dave Shepard on November 04, 2017, 08:24:36 PM
My boiler is just about to start it's fourth heating season and the circulator on the wood side conked out. It was a used 009 that ran about 26,000 hours non stop. Had a few spare circulators of unknown quality, and found one that worked. :D I don't know what size if is, but the door on the boiler won't close now. Probably an 011. Going to have to hit my plumber up for some more spares. That's getting harder now that he's pretending to be retired. ;D
The heat exchanger is pretty amazing. 207° water going in, outlet doesn't even feel warm. House is down to probably 60° water temp, so its really taking the heat.
I have a pile of pumps in my garage and none worked as good as the NRF36 I have on it now. I actually put one on the house side too now. Before on really cold days I would see into the 60s with baseboards that were only mildly warm.. I put the NRF on the outdoor boiler first and problem solved, the heat was exchanging. Then I put one on the house side as well and it helped there too. My baseboards get really hot now, they actually tick quite a bit and the difference is night and day. Burns less wood too.
Its 3 speed manually adjustable and can handle some serious head ratings.