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[Bluegrass Wood Burner]

Ok That's what I will do. I have plenty of room on back of my boiler. Ill check the return temps first. I'm in Detroit for next couple days. My wife and 25 year old son are taking turns manning the boiler while I'm gone.

[Bluegrass Wood Burner]

My return temps are good. I'm loosing around 8 degrees in my exchanger. The problems I have been having are indeed caused by poor mixing of water inside my boiler. I bought an Armstrong pump today and am gonna mount it to pump water from bottom to top. I'm wandering if I should let that pump be controlled by a aquastat that is monitoring water temps of the supply water. If supply water drops to a set temp let the pump kick in and run until temps come back up on supply side. This would save some electricity and save life of a second pump. What's your thoughts on this? Should I just let it run constantly? Also I'm thing of putting a filter on with this pump so water can be filtered while circulating.

[E Yoder]

Personally I'd just let it run. Or just plug it in during cold weather when you need max temp supply water. Starting and stopping is harder on a pump than running. But it'll work either way. An aquastat would take several years to pay for in electricity savings.

[Bluegrass Wood Burner]

Good point yoder. Thanks

[wreckit87]

I'd also let it run. Just low speed will be fine with no head. Any reason behind pumping return into supply though and not the other way around? I always do it the other way but only did it because that's how they want the load piped so figured it'd be the same with a shunt

[heat550]

You know I have played with fans and ex changers and baseboards .. I have 152-160f degree water going to 60,000 btus exchanger
and about 1200 cfm on exchanger temp drop is 10-13 degrees at -21f  keeps the house 76f  28x48 house what part am I missing that everyone need that water temp at 175 f  I also have a 100,000 btu exchanger with a 500cfm fan heating shop 32x32 keeps what ever I set it  pull as much as 19 degrees off water . my boiler does same thing top of tank can be from 165-185f when im burning slabs
you just -10 degrees and thats what lower output temp is in the house .. Baseboards you cant get a enough heat to them there for slow small room heating in my book . ( bedrooms bathrooms etc.) I think ductwork and fan air flow is a bigger deal . 150f air coming off a exchanger when water 175f will take your breath away stinking nasty hot . don't like fan noise get quiter fan there's nice ones out there . Last thought check your in ground lines and see how much heat there robing . 
this my findings with heatmor 400 and 200 . and older houses 1976 and 1991

heat550

looked on the website ozark there pulling water out the of top of the tanks this give you wild temps . mixing would be totally different then my setup.

[Bluegrass Wood Burner]

On the left side of back of the boiler there are two ports not being used. I'm just gonna run a pipe from the bottom one up to the top one. Mount the pump between them. So I'll be bringing water from bottom of boiler and pushing up to the top. Hoping that will solve my issues.

[wreckit87]

On the left side of back of the boiler there are two ports not being used. I'm just gonna run a pipe from the bottom one up to the top one. Mount the pump between them. So I'll be bringing water from bottom of boiler and pushing up to the top. Hoping that will solve my issues.

Why backwards? I feel like that may introduce colder water to your supply line to the house and not help a lot. Any reason not to go from supply to return like the MFG wants? Unless you swap the house loop to bottom supply also, I feel like they might fight each other

[Bluegrass Wood Burner]

One more question for you all. I have Grundfos 26-99 3 speed pump as my main pump. I bought this pump yesterday and it's a single speed. Which would you run where? Should I make the Armstrong my main pump and use the Grundfos as the shunt or the opposite. I got a really good deal on the Armstrong so I couldn't turn it down. Probably overkill either with pump as the shunt. Do any of you know anything about this new pump I bought. It's like new hardly used at all and I gave 25.00 for it. 250.00-300.00 on eBay

armstrong-s-25-bf-in-line-circulator-1-12-hp-pump-174031-013-cast-iron

[wreckit87]

That one is really low head. I'd put it on the shunt side if you're deadset on using it and leave the Grundfos where it is. Personally I would've spent another $40 and bought a 15-58 sized for the application but that's just me. I'm going to ask one more time, what your reasoning is behind pumping from return to supply with the shunt?

[Bluegrass Wood Burner]

I'm not really sure why I was gonna go in that direction, I think just to be opposite of the other side. So you say pump from top down to the bottom like I'm doing on the right side ? I will take your advice on that. Thanks for doing the double take and getting my attention on that. I really had not intended to buy a pump the size of the Armstrong but I couldn't pass up that kinda deal. What about putting a water filter I this small loop. Put a pressure gauge on it and when the pressure starts rising I'll know it needs replacing My water seems to have a lot of sediment. Might prevent exchangers from clogging down the road.

[wreckit87]

I'm not really sure why I was gonna go in that direction, I think just to be opposite of the other side. So you say pump from top down to the bottom like I'm doing on the right side ? I will take your advice on that. Thanks for doing the double take and getting my attention on that. I really had not intended to buy a pump the size of the Armstrong but I couldn't pass up that kinda deal. What about putting a water filter I this small loop. Put a pressure gauge on it and when the pressure starts rising I'll know it needs replacing My water seems to have a lot of sediment. Might prevent exchangers from clogging down the road.

Triple take, actually lol. I may be out in left field here, but I feel like bringing constant cold water from the bottom and dumping it in the top near the supply to the house is going to cool your outgoing supply water to the house. Just seems to me the flow should be in the same direction in each set of ports. As far as the filter, are you thinking like a whole-house type filter with the clear housing so you can keep an eye on it? Otherwise a regular old $20 cast iron y-strainer with a ball valve on the outlet works well also. No pressure gauge needed, you can just open the valve once in awhile to blow down the crap caught in the screen without having to change anything else, only takes a few seconds and they catch a lot more than one might expect them to. The canister style seems to be the way to go but I don't know if I'd want that in the boiler to be changing filters when it's below zero. Most put them in the house loop somewhere

[racnruss]

I believe your goal is to equalize the temperature in your boiler, correct?   Just try it one way or the other and see if it works.

Also, have you measured your supply water temp as it leaves the boiler toward the house, and then compared it with what you have at your heat exchanger?  Such as using an infared heat temp gun?   Meaning, are you sure you are not losing a bunch of heat to the ground?

Let us know what you find. 

[Bluegrass Wood Burner]

When the boiler cycles with combustion fan on and begins to really blaze the whole unit vibrates a little and I feel this vibration mixes the water a bit and that's when the temp goes up on the exchangers inlets at my air handler. When its sitting their in idle very quiet and calm with very little coming out the stack that's when the temps start dropping inside at the exchanger inlets. I have 178 temps on supply side when its right, then that drops to 150 when I still have 180 at the boiler. There's no way I'm getting the maximum efficiency out of my boiler when the water is not mixing and my return water is going back out without getting heated back up. I'm losing around 18-22 degrees in my loop when the blowers in my air handlers are running. I have two exchangers side by side. When the blowers are not running I'm losing about 4-6 degrees from one end of exchangers to the other. I believe all those numbers are pretty good. However when I'm trying to heat my house with the 150-155 inlet temps and 130-135 return temps its laboring a bit. At times when its in 0-5 degree range outside my temp on my thermostat my be set at 173, but the actual temp in house is 171. This has happened quite a bit this year. I'm heating 5400 sq. ft. of well insulated with good windows. I feel the only way my boiler will give me all it can with my setup is if my water temps are from 165-175 on supply side in air handler at exchanger, and 145-165 return temp.
I have my Armstrong pump ready to install as a shunt. I know its much more pump than I need for this situation. Will the 30gpm be Ok for the mixing effect. Is the overkill gonna cause me any other problems. I'm just gonna put a galvanized pipe from bottom to top on the side of my boiler that's not being used at all and mount this pump at the top of that pipe. Therefore taking from one port and send to another.  I feel this extra circulation will solve these inconsistencies.   
Several have said if it heats your house just be satisfied. I just don't look at it that way. Its like using a chainsaw that doesn't cut straight. It will cut and eventually get the tree cut up. I cut wood with sharp straight chains and I want my boiler to be what's its supposed to be. My wood usage is up this year. It has been around 12 cords but this year more like 15-16. Its been cold, but some of it may be the mixing.     

[wreckit87]

DO NOT USE GALVANIZED PIPE in a hot water heating system, you will be disappointed. The galvanizing will flake off and eventually corrode to a point of pinholes and paper thin pipe walls. Use black pipe for anything requiring the rigidity. As for the overkill on the pump, there is no such thing as too much mixing. Depending on the design, you may find some turbulence inside but if you have isolation valves at the boiler, which you should, you can easily throttle the one on the pump discharge to slow flow down if it causes any issues.