CD 6048 Boiler - Air In Pipes Through Attic - No Flow

[LegendsCreekFarm]

This install is 98% done for me. My CB 6048 is working great heating my house and workshop, but I am having trouble with my guesthouse getting air in the pipes which is causing the flow to stop at the pump.

I ran the pipes underground from the boiler, and then up the side of the house, through the attic, and to the boiler room where the Taco 011 pump is 1 foot off the floor.

I keep purging the air out of the lines by running garden hose water through both the supply and return. Air gets pushed back to the wood boiler and everything seems great.

I start the pump back up and it starts running, but still not getting the best flow. After a few hours its bringing hot water to about the pump, but not enough force to push it all back through the exchanger and return to the boiler.

I don't believe there are any leaks in the lines. I have no idea how air is getting in, I am almost cerain there are no leaks, but perhaps I just havent gotten it all out, or its coming in microbubbles and then building up and clogging the lines.

My pump is a bit overkill based on my head calculations, but the other option would have been the 014 and it would have been under so I would rather be over than under.

Should I install an automatic hy-vent and get the air out, on a tee, and put one in supply and one in return, at highest point in the attic? Should I also install another at the inlet before the pump? I do notice air bubbles in the lines being sucked toward the pump after it runs a little while.

Here is a diagram of my install. I have a slab and septic in the ground so this was my only option. I do not want to pump attached to the wood boiler and I decided to install it in the boiler room line with my shop and house which are working great. Any help you all could give would be appreciated!

 

[leon]

You have hot water circulator not a hot water pump.

Did your Central boiler dealer tell you to put it there?????????????
IF SO HE Needs to be taken to the woodshed!


The major problem you have right now is that your "circulator" IS IN THE WRONG PLACE.
It must be, it needs to be moved from the guest house close to the wood boiler sump where it
belongs as you can suck all the air you want out of the system its case of whether it will move or not.


Invest in copies of the books "Pumping Away" and "Classic Hydronics" written by Dan Holohan and
available at AMAZON or (broken link removed), buying these books from Dan's Books
allows all proceeds to go to the author who self publishes his books.

Move your circulator to the base of the boiler UNLESS its pressurized system(install it above
the boiler then) and you will get rid of your air issues without having to bleed anything anywhere as
all your circulator is doing now cavitating for the most part.

 

[LegendsCreekFarm]

Thank you for the info. I did this install myself. I need to do this for multiple reasons and installing it at the boiler is not an option so I followed my neighbor who has the same boiler and has been running his with the pump in boiler room for 9 years with no issues.

When I first began this project 6 months ago I didn't even know what cavitation was and I have learned a lot about it. If moving the pump is the only option then I will need to install it at ground level, outside the guest house but I would really love to avoid this. I need the pump on the same electric panel as the guesthouse, and tied to the same aquastat as my wrap around pump.

 

[hondaracer2oo4]

You did not explain why you have to have pump located at the house. You might be able to place the pump at the same elevation of the outlet feeding the pump from the boiler but you can't put it above that point or have any type of high loop in between. If this was a pressurized system where the water is in a closed air tight loop you can put the circulator anywhere in the system. But since you have a unpressurized system then You have a pump and the intake side of the pump needs to have atmospheric pressure pushing water to the pump intake.

 

[leon]

Thank you for the info. I did this install myself. I need to do this for multiple reasons and installing it at the boiler is not an option so I followed my neighbor who has the same boiler and has been running his with the pump in boiler room for 9 years with no issues.

When I first began this project 6 months ago I didn't even know what cavitation was and I have learned a lot about it. If moving the pump is the only option then I will need to install it at ground level, outside the guest house but I would really love to avoid this. I need the pump on the same electric panel as the guesthouse, and tied to the same aquastat as my wrap around pump.

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You have to move the pump period. Placing the "Hot Water Circulator" outside will cause you to lose this Hot Water Circulator to freezing and the freeze damage caused by the impeller case breaking from expansion will drain the boiler dry.

The only help I can offer is the two books I mentioned to you as you are not going to have satisfactory results with your current circulating system.

Your dealing with basic hydraulics but using water.

Why is it you have no room inside the boiler shell to set the pump and the BX cable to power it???

Your Hot Water Circulator has to pull the water and air through your system to get rid of it.

Installing a heat exchanger will not solve this for you either. You are going to have to go back to the beginning and read the books I recommended to you to solve this soon before the weather hits the manure spreader beater.

Your system as it stands now has no point of pressure change and needs to be corrected to let the Hot Water Circulator work properly as your hot water circulator impeller is just churning.

I am not trying to spend your money I want to help you.


By renting running a walk behind LP gas line trencher to run the power cable for a L4006A to power the circulator and then mounting the circulator on the inside of the boiler shell and the thermostat wire to the boiler will work for you as the water line is already in place.

 

[LegendsCreekFarm]

I did explain why I can't put the pump at the boiler. I have a septic system in between the boiler and house. I cannot trench a new line. I need the pump wired to the same aquastat and electric panel as the guest house which is why I located it inside the guest house boiler room.

Honda, I didn't think about the loop at the top where it goes through the attic. So basically you are saying that even though the pump is a foot off the floor in the boiler room, because of that loop through the attic, it won't pull the natural pressure from the boiler outlet like it would if I had the pump installed at the boiler itself?

The pump won't freeze outside. I am building an insulated outside "closet" to house the exposed pex lines and possibly the pump if I have to move it, so if I relocate it to ground level where it meets the side of the guest house, do you think it would help?

 

[leon]

I did explain why I can't put the pump at the boiler. I have a septic system in between the boiler and house. I cannot trench a new line. I need the pump wired to the same aquastat and electric panel as the guest house which is why I located it inside the guest house boiler room.

Honda, I didn't think about the loop at the top where it goes through the attic. So basically you are saying that even though the pump is a foot off the floor in the boiler room, because of that loop through the attic, it won't pull the natural pressure from the boiler outlet like it would if I had the pump installed at the boiler itself?

The pump won't freeze outside. I am building an insulated outside "closet" to house the exposed pex lines and possibly the pump if I have to move it, so if I relocate it to ground level where it meets the side of the guest house, do you think it would help?

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A propane trench line is only 3 inches deep on average and you can use direct burial cable in a shallow trench. You could use some black poly and run the power and thermostat cable together.


You have a huge slug of air there and it will not go away no matter how hard you try to bleed the system.


That will work for you as long as the "shed" door, walls, roof, and floor is insulated and you have at least one light bulb in a ceramic light fixture in it to heat it at all times. Without a heat source the interior of the insulated pump house will hold the cold in as well as keep it out so you need a light bulb to keep it hot in there.

 

[LegendsCreekFarm]

I have a skid steer so digging a trench would be easy but its not something I can do right now, but I would like to try to mount the pump on the outside of the house and build that shed. (I have to build it anyway to insulate the pipes outside as I only used thermopex in the ground).

You mention the light inside. I didn't think of that. The pump house would hold the cold in, even with the pump running most of the day, and full insulation in the shed?

 

[leon]

I have a skid steer so digging a trench would be easy but its not something I can do right now, but I would like to try to mount the pump on the outside of the house and build that shed. (I have to build it anyway to insulate the pipes outside as I only used thermopex in the ground).

You mention the light inside. I didn't think of that. The pump house would hold the cold in, even with the pump running most of the day, and full insulation in the shed?

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So your saying the boiler has no room in the access panel area to mount the Circulator in the sump tapping with a pair of circulator mounting flanges?

Your shed will become an icebox every time you open the door and close it unless you have an incandescent light bulb or two of them in it mounted in the ceiling of the shed.

I would see how much the slit trencher would cost you to rent for a half day and be done with it. as it would cost you less money to buy the direct burial cable, black poly pipe, thermostat wire and the L4006A if it were me. All you would need to do is rent a tape snake to pull the 14/3 direct burial cable and the thermostat wire pair through the black poly pipe BEFORE you push it in the trench..

The slit trenchers are the size of a walk behind lawn mower so...

 

[warno]

I agree with leon on moving your circulator closer to your boiler but I don't agree that your little shed off the building will become an ice box. Alittle bit of insulation goes along way in a small area.

 

[LegendsCreekFarm]

So I moved the pump to the ground level, just outside the guest house. The fix was instant. It pushed all the water and air right through, I bled everything and now its moving a ton of water and went through the heat exchanger and my oil boiler temp went from 100 degrees to 190 in less than 10 minutes.

I know this is not the ideal location for the pump but I am beginning to understand how this works and have learned a lot over the last few months. Its best for my set up to have all the pumps in the buildings they bring heat to. I have been in the process of making my property "wifi" so I can control everything from my phone. This may not be the best set up for this zone but if so I will fix it next year, but I am hopeful it will work.

The pump is running almost silent now and has done exactly what I needed it to and I will keep it where it is so long as I don't blow through cartridges and it doesn't freeze up being in a shed. I think the heat from the pump will be enough to keep it warm without the light bulb idea but I will probably install one anyway!

Thanks so much for the advice!!

 

[warno]

I would, if at all possible, put all the pumps as close to your boiler as you can. I wouldn't hesitate at all to bury the power lines and thermostat lines in the ground to get the info and power to your pumps. Just remember you can't run high and low voltage in the same conduit. As far as your shed freezing up just put a lining of pink foam insulation on the walls and you should be fine. If Your water is over 32 degrees nothing is freezing anyway. I had a friend build a small box to cover his sump pump dump in his yard. He lined it with 1.5" pink foam and that's it. Nothing froze up. And that was just water pumping from his sump not even hot water.