Primary-secondary pumping system

Dan Peel

The oo7 on the mini loop looks to be purely for boiler protection. By controlling it to come on only if the return temp to the boiler dips too far it can still serve that purpose. Elimination may not be in the best interest of boiler longevity. Dan

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Chad Brickley

Primary-secondary system

I have some problems with a 2 year old system. I have attached a document with the system description and pictures with fair detail. Anyway, the system was not exactly what I planned with over a year of research. It has worked well so far, but during this week of zero degree temps outside, my system is having a true test and failing in a big way. I believe the problems could be directed to the controls, but I am desperate for any suggestions. The problem is that my house is cold, 62-64 degrees cold, and I can't explain why. The boilers are making water at 180 degress, the primary loop is 130 at max and should be going higher when needed (now) but is not. The thermostats are set for 70 but have not seen that for days, the secondary pumps are on constantly. I know its cold, but is this a problem with the system vs not enough radiators. Even in our master bedroom, with three radiators and its own zone, the temp is 64 at best. When the outside temp is 25-30 or higher, I have no problems, but I haven't been completely satisfied with the system since day one, because I had no good explanation for the design of the layout and system and fearful of the problem at hand. Any and all comments welcome, let me know if more information may be helpful.

Thank you.

Dan Peel

Run don't walk

To the "find a contractor" area on the left - find a close one and pay their rate for a system review and repair. Fronm the pictures supplied you had the benefit of good mechanics BUT with many of the circulators inverted it would suggest their main diet was not hydronics. If as you say the radiation was chosen and placed to match a proper heat loss then the physics of the system are apt to be easily corrected. Dan

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Jerry Boulanger

You may be recirculating cold

return water if the flow in the secondary is higher than the flow in the primary. Cold return water is mixing with hot boiler water, with the net result being cooler than comfortable secondary supply. You may have to throttle the flow in some of the secondary circuits to prevent this.

Arthur

Primary-Secondary System

Nice installation, But
1) Tend to agree with Dan Peel, The circulators should always be installed with the motor shaft in an Horizontal configulation.
2) Can not figure out why there are 2 primary pumps, 1 down by the boiler and the other up by where 'constant circulation ----- -- (note3)' It is bad practise to have 2 pumps in series as they will tend to fight each other.Disconect one or the other.
3) The primary circulation should be from the far ends of the primary headers, ie. the pump is tending to draw water past the flow outlet off the header and draw water back past the return inlet on the header.
4) The connection were it says 12" max should be isolated.
5) The primary header should NOT create any flow pressure to the zone circuit, Thats what the zone pumps are for.

What you have is a 'primary/primary/secondary system. 1 primary with the pump down by the boiler, a sec primary with the second pump up by the 'constant ------ (note3)' and the secondary pumps on the flow to each zone. 1 pump too many.

From your comments the problem is in the fact that the header is not getting up to temperature so that the water going to the zone is never going to get to temperature either. The top primary pump is going to pump the water around in circles rather than pulling it up from the boiler. Especially if the bottom primary pump is weaker than the top pump (it is very difficult to get pumps to balance aginst each other)
Hope this helps.

Arthur

Primary-Secondary System

Sorry double post.

Frank_3

Somebody goofed.

Chad, the system you're describing (and show in the photos) does not match the sample piping diagram you got from the manufacturer. Was that your idea or the contractor that installed it?

The first thing I would do is disconnect power to the 007 on the "mini loop" and close off those two isolation valves on either side of the circulator. I suspect the 007 is stealing water from the piping where the secondary zones are connected, and that mini-loop serves no purpose since the design strayed from the sample.

Could you sketch out and post a drawing of how the two boilers and DHW are actually piped?

Frank_3

One more thing ...

Can you post a photo that shows the piping behind the boilers, from the left side? That would show the boiler return to go along with a piping sketch.

Chad Brickley

Thank you

Thank you for the input. The design in the drawing was not my idea, I spent a year reading Dan's books and talking with contractors, 10-15 , that did not want to or know how to "pump away." When i found somebody that was understanding of the pumping away and designed the system, my worries went away. But I soon realized that he was not completely understanding of the physics behind the system, although hands on he did a great job, I think when talked with the rep who supplied the diagram, the optimal system that I paid for did not happen. Frank, I will get the sketches and pictures and post them next 24 hours. Thank you for all the input.

Frank_3

The 007 in the mini-loop and the 0010 on the maxi-loop (or the primary loop if you prefer) are both on constant circulation according to Chad's notes. So I hardly see how the 007 is of any use.

Since the 007 is seeing hardly any pressure drop in the mini-loop it must be moving quite a bit of water. That's leaving less water to move through the primary loop so it could be contributing to the problem.

Boiler protection would, I think, be controlled by the temperature sensor in the primary loop. By not allowing water in the primary to get too cool, the reset control also protects the boiler.

I suspect there's something going on with the boiler return which we can't see from the photos. I'll wait for Chad to post the follow-up.

GW

my two cents

I just blurried my eye balls a bit- Is it my imagination, or are the supplies coming of the Pri AFTER the returns?? It seems to me that the boiler supply is piped to the right, return on the left, air scoop on the right, so primary flow to the Right... correct? Then what da heck are the returns coming in before the supplies?

Maybe I'm tired, but I've never seen flow checks before the circs.. I guess there's no law against this, but I'd rather see the pump pushing the weights open instead of pulling them open...

Someone mentioned the 007 circ that acts as a boiler protector, my goodness, throttle that sucker down!

And please do turn those circs the right way.

Can you get temperature readings before and after the 007, on BOTH sides of the boiler? (4 measuring points please... I bet this circ is robbing all the flow)

Please let me know if I stayed out too late tonight... Good night wet heads.

Gary

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GW

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GW

one of my jobs

Pri Sec

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Chad Brickley

pictures

Ihave attached a few shots that may make things more clear. Unable to get a scanned diagram in short time. The way the DHW is piped, the supply is 3/4" coming off the main supply. The supply does not have a pump. The return piping is shown, has a valve, 007, valve and returns to the main return at the bottom. Neither the main supply or return on either boilers has a pump. that was a concern I had during construction, why no pump on the supply of each boiler?

The advice was helpful regarding the mini-loop, I did turn the pump off, close the valves, the primary loop is reaching higher temps now and the house is warmer.

But I still have concerns regarding the pumps and locations.

Hope these photos and info shed light into the questions.

Chad

Chad Brickley

I attached a picture of the main return and supply. You are correct, the return is first, then the supply, the temp sensing unit, air scoop all from left to right and the flow is counter clock wise or towards the right.

Are the return and supply to close, ?need pumps.

Thank you for the input

GW

What did I miss?

There are no pumps on the boilers? I'm not familiar with that brand, I incorrectly assumed that there were circs inside the boiler jacket. That's reall strange, I'm suprised the house heats up at all.

The tees normally are within 6 pipe diameters per set, and at least 8 pipe diameters between the different pairs,or sets, or whatever you want to call them.

Gary

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GW

the pumps

are sent with the boiler... were oh were are they now?

http://www.dunkirk.com/pdfs/Quantum90.pdf

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Frank_3

Are you an NRA member, Chad?

...because you're going to want to shoot the contractor that designed and installed that system.

I was honestly thinking that there was no pump in the boiler loop, but I said to myself, "Nah, nobody would actually do *that*, right?" That's why I wanted to see pictures of the boiler return -- I couldn't tell from the photos you originally posted whether there was a pump hiding down there.

With no pump in the boiler loop, there's nothing to coerce hot boiler water into the primary loop. How it's happening is anyone's guess -- probably the DHW pump is having some influence as well as gravity and pure luck.

A quick fix to get some additional heat would be to take the 007 from the mini-loop and install it in the boiler supply -- chop out all of the mini-loop piping if you have the time. One of the photos shows a pipe hanger holding the boiler supply after the tee which joins the two supplies together -- move that hanger to make space and put the 007 right there, pumping towards the primary loop. With the circulator in that position it should be wired such that it kicks on whenever the reset controller calls for warmer water in the primary loop.

There are other problems as well, but having a boiler circulator may mask them well enough to where you can heat the house sufficiently. Here are some things that you may want to address when the weather is warmer ...

a) Gary Wilson is correct in pointing out that the zone supply and returns are flipped. The supply should come first in the direction of flow through the primary loop. With the returns and supply piped as in your system the return water is cooling the primary loop water, which then gets pulled back into the zone loop. The zone always ends up getting water that is cooler than the primary loop water.

b) There are no flow-checks in the boiler loop, nor the DHW loop. From the DHW view, what's guaranteeing that the water entering the DHW loop is coming from the boiler and not the primary loop? Nothing other than the DHW loops proximity to the boiler supply. In fact, that may be why you're getting any heating of the primary loop at all.

In addition, there's nothing to prevent reverse flow through the idle boiler when only one of them is running. If you put the 007 in the boiler supply, there's the chance it will circulate water through the DHW loop in reverse as well.

c) As for circulator orientation, the only two I see a problem with are the mini-loop and the DHW circulator. The mini-loop circulator is going bye-bye so who cares. The DHW circulator should be rotated so that the motor is parallel to the floor, with the wiring box on top. It will actually work for years the way it but it's not recommended by the manufacturer.

Best of luck.

Frank_3

Are you an NRA member, Chad?

...because you're going to want to shoot the contractor that designed and installed that system.

I was honestly thinking that there was no pump in the boiler loop, but I said to myself, "Nah, nobody would actually do *that*, right?" That's why I wanted to see pictures of the boiler return -- I couldn't tell from the photos you originally posted whether there was a pump hiding down there.

With no pump in the boiler loop, there's nothing to coerce hot boiler water into the primary loop. How it's happening is anyone's guess -- probably the DHW pump is having some influence as well as gravity and pure luck.

A quick fix to get some additional heat would be to take the 007 from the mini-loop and install it in the boiler supply -- chop out all of the mini-loop piping if you have the time. One of the photos shows a pipe hanger holding the boiler supply after the tee which joins the two supplies together -- move that hanger to make space and put the 007 right there, pumping towards the primary loop. With the circulator in that position it should be wired such that it kicks on whenever the reset controller calls for warmer water in the primary loop.

There are other problems as well, but having a boiler circulator may mask them well enough to where you can heat the house sufficiently. Here are some things that you may want to address when the weather is warmer ...

a) Gary Wilson is correct in pointing out that the zone supply and returns are flipped. The zone supply should come first in the direction of flow through the primary loop -- the boiler supply is positioned correctly. With the returns and supply piped as in your system the return water is cooling the primary loop water, which then gets pulled back into the zone loop. The zone always ends up getting water that is cooler than the primary loop water.

b) There are no flow-checks in the boiler loop, nor the DHW loop. From the DHW view, what's guaranteeing that the water entering the DHW loop is coming from the boiler and not the primary loop? Nothing other than the DHW loops proximity to the boiler supply. In fact, that may be why you're getting any heating of the primary loop at all.

In addition, there's nothing to prevent reverse flow through the idle boiler when only one of them is running. If you put the 007 in the boiler supply, there's the chance it will circulate water through the DHW loop in reverse as well.

c) As for circulator orientation, the only two I see a problem with are the mini-loop and the DHW circulator. The mini-loop circulator is going bye-bye so who cares. The DHW circulator should be rotated so that the motor is parallel to the floor, with the wiring box on top. It will actually work for years the way it but it's not recommended by the manufacturer.

Best of luck.

Frank_3

Are you an NRA member, Chad?

...because you're going to want to shoot the contractor that designed and installed that system.

I was honestly thinking that there was no pump in the boiler loop, but I said to myself, "Nah, nobody would actually do *that*, right?" That's why I wanted to see pictures of the boiler return -- I couldn't tell from the photos you originally posted whether there was a pump hiding down there.

With no pump in the boiler loop, there's nothing to coerce hot boiler water into the primary loop. How it's happening is anyone's guess -- probably the DHW pump is having some influence as well as gravity and pure luck.

A quick fix to get some additional heat would be to take the 007 from the mini-loop and install it in the boiler supply -- chop out all of the mini-loop piping if you have the time. One of the photos shows a pipe hanger holding the boiler supply after the tee which joins the two supplies together -- move that hanger to make space and put the 007 right there, pumping towards the primary loop. With the circulator in that position it should be wired such that it kicks on whenever the reset controller calls for warmer water in the primary loop.

There are other problems as well, but having a boiler circulator may mask them well enough to where you can heat the house sufficiently. Here are some things that you may want to address when the weather is warmer ...

a) Gary Wilson is correct in pointing out that the zone supply and returns are flipped. The zone supply should come first in the direction of flow through the primary loop -- the boiler supply is positioned correctly. With the returns and supply piped as in your system the return water is cooling the primary loop water, which then gets pulled back into the zone loop. The zone always ends up getting water that is cooler than the primary loop water.

b) There are no flow-checks in the boiler loop, nor the DHW loop. From the DHW view, what's guaranteeing that the water entering the DHW loop is coming from the boiler and not the primary loop? Nothing other than the DHW loops proximity to the boiler supply.

As I mentioned, that may be why you're getting any heating of the primary loop at all. If the DHW circulator is pulling some of its flow from the boiler and some from the primary loop, that means that it must be returning water to both the primary loop and the boilers. The water that it sends back to the primary loop is going to be warmed to the boiler temperature.

In addition, there's nothing to prevent reverse flow through the idle boiler when only one of them is running. (And I'm assuming they're wired so that only one comes on if demand isn't sufficient to have both running -- otherwise why bother with two?) If you put the 007 in the boiler supply, there's the chance it will circulate water through the DHW loop in reverse as well.

c) As for circulator orientation, the only two I see a problem with are the mini-loop and the DHW circulator. The mini-loop circulator is going bye-bye so who cares. The DHW circulator should be rotated so that the motor is parallel to the floor, with the wiring box on top. It will actually work for years the way it but it's not recommended by the manufacturer.

Best of luck.

Frank_3

Me again ...

I see that while I was working on my essay Gary replied about the missing boiler circulator as well.

David Van Wickler

Not enough boiler

is the boiler in the primary loop? Is the making it to the high limit, i.e. shutting off when it is bitter cold outside? If it runs and runs and isn't making temperature then the boiler is not producing enough BtuH.

If the boiler is shutting off on high limit then the primary pump is too small.

Chad Brickley

Missing circulators

The boilers did come with pumps, but the contractor decided to use them for zone pumps. Many of the issues being raised are the questions I had 2 years ago, and for what ever reason, I had some faith in the heating contractor. That lasted only a short time after all was up and running, had a few minor issues with poor service and understanding. Now I am faced with a project that my cost several thousand to fix.

One question regarding the Taco 010 on the primary loop, 3 o'clockk position. Keep it or move it? Also, should the supply for the DHW have a pump and flo-chek, and eliminate the pump on the return aspect? Many of these may be stupid questions, but I need to know so this does not happen with the repair.

The information has been helpful and I thank everyone for the insight.

One last question, does anyone favor tekmar vs. taco vs. argo control panels, or is it the person using them?

Steve Eayrs

tekmar or taco?

tekmar is ahead of most on the controls, and in fact taco uses tekmar parts on some of their controls, but the bottom line is only getting what you need, and can get parts/service for.
Am sure there must be someone in your area who understands boilers better than your last guy. Doesn't take too much knowledge to know "pumping away" should involve a pump.
Will never understand why its so hard for some guys to just say, I don't know, and go do, what they do know. Its a good reminder to always ask for references. Guys like this usually leave trails.
Sorry to hear of your misfortune.
Steve

Wayco Wayne_2

Why ?

Why would you need a boiler protection loop with a condensing boiler?? Let it come back cool. The cooler the better. The cooler the more efficient.

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