buffer tank running boiler

Dave_61

currently, we have a swingcheck valve in the 2" pipe that goes from the boiler to the Ergomax. Would that take care of the checkvalves in the boiler circuit?
Also, each individual zone pump in the supply header has its own flowcheck mounted just downstream oof each pump. Would you still recommend installing another swingcheck in the return header (since the flowchecks on the supply side should prevent any backflow of water into the returns)?
Thanks.
Dave

Dave_61

buffer tank wired through TT on boiler

We have placed a buffer tank for our copper tube boiler and are running heating zones via supply and return headers attached on return piping between tank and boiler via 2 closely spaced tees. The way I have the system wired is that when any individual zone pump runs, the circ that goes between tank and boiler also runs.
I tried running just individual zones without running boiler circ, but the zones would not get up to temp. Therefore, the boiler circ must always run when any zone pump is running on supply header.
I have the aquastat from the buffer tank wired through TT on boiler, so all the buffer tank will do is turn on the burners. We have a flow switch so if there is no flow in boiler/buffer tank loop, boiler will not run.
The boiler circ is independently controlled by our Taco SR504 switching unit. Again, the boiler circ runs whenever any individual zone pump is running.
We have a Phase III indirect as one of the zones. So, if the buffer tank ever called for heat without any other zones running, the boiler would lock out (as the boiler circ would not be running).
Could there ever be a scenario where the buffer tank would call for heat without any of the individual zones calling for heat? Maybe in the summer? I would think that using the domestic hot water from the Phase III would always cause the buffer to call for heat along with the Phase III so the boiler circ would still be running.
Would there be an easier way to wire this so that the buffer tank runs the burner and boiler circ, but the individual zones only turn on the boiler circ without allowing the burners to fire?
Thanks.
Dave

Joe Brix

Any pictures yet?

I don't think you should need the primary circ running if this is piped right. I would expect the primary circ to run only when the boiler was firing to put BTU's into the buffer tank. The zones pull BTU's out. The boiler is de-coupled from the zones.

Dave F_2

Joe,

My digital camera is not working yet, but let me explain what we have.
Coming out of the boiler return from the tank, the 2" copper pipe going back to the boiler has 2 closely spaced tees. the first tee has the supply header with all zone pumps.
The second tee has the return header with all returns from zones.
Then the 2" copper pipe continues to the boiler via a 0010 pump that pumps into the boiler inlet.
When we tried running just the individual zone pumps, the hot water would not travel up into the supply header. I was told that the individual pumps (007's) do not have enough oomph to continue pushing the water through the stopped 0010. As soon as we started the 0010, everything started heating well (as it started circulating water through the boiler/tank loop). What do you think?

Joe Brix

It sounds

like you've made the Eromax part of the primary loop with the boiler. The heating and indirect zones are the secondary. As such, you need to run the 011 to bring the buffered water in and out of the buffer tank.

To have the boiler only use the 011 to put heat into the boiler, then the zone circ's to pull heat out, you'd need to have used a buffer tank with 4 tappings.

This the real right way to do it, but you still need the primary circ running when any other circ runs. Also uses an extra pump:


http://www.pmmag.com/CDA/Archives/bcf53d9e1efc7010VgnVCM100000f932a8c0____

Dave F_2

We actually

did do it in series with the boiler as that is what Adam at Ergomax recommended.
I'm thinking of completely disconnecting the Ergomax thermostat from the system and running it as before....any zone pump will start boiler circ pump and then boiler once water drops below setpoint.
Then I would add Heatmanager to supply from boiler to act as a type of reset. What do you think?
With the Heatmanager, what would you set operating temp and high fire temp on boiler?

Mike E_2

I have the Heatmanager on my boiler and have found that the supply temperture has to stay above 150F. Otherwise, the unit will not economize and go straight to firing. I have my aquastat set at 180, with a diff of 20.

Michael

Joe Brix

Never used the Heatmanager

I don't think it knows about set temp. It just takes it's own temp of the boiler and watches how fast the temp drops. If the water is still warm, it will hold up firing the burner if it gets a call from the thermostats on the TT terminals. Just a fancy differential. It doen't know that you have a big buffer tank. It just tries to help regular boilers not to fire every 5 minutes as one zone after the other calls. (That's why it's cheap, no digital display, setting, outdoor sensor, etc) There;s a higher end model, but that was more then a tekmar 262. The buffer tank is doing the work of the heatmanager. The larger water mass extends burner cycles and the occur less frequently.

My question, is the 150° boiler temp keeping the house warm and does the Phase III recover fast enough. What about when the temps are in the teens or less? If you see you need to boost the overall temp up when it gets colder out, then you really need outdoor reset, IMO.

If you feel the indirect is not recovering fast enough but the heating zones are OK, I would get the Tekmar 262.
It would control the 011 and indirect's circulators. It would also control both firing stages. It can be set to wide differentials and still fire to the max temp limit when the indirect calls for heat.

Dave_61

Michael,

How do you like the Heatmanager? Our operating temps tend to be around 170, which is what they recommend.

Dave_61

Joe,

This is what I've seen so far with our setup....currently, the boiler is set to fire through the Taco pump relay SR506. The boiler circ is wired through the internal boiler relay. So when any zone calls for heat, the boiler circ starts pumping and the burner(s) come on when the temp gets below the boiler setpoint.
I currently do not have the Ergomax aquastat hooked up to anything.
The one problem I see occurred today when all zones were off for a while. The Ergomax was at 160 or so. But as soon as one of the zone pumps turned on, the boiler saw an inlet temp of 130 as the boiler piping had cooled down. So the boiler started immediately. Would it make sense to have the 0010 circulate constatnly to have the hot water from the Ergomax going through the boiler?
The Tekmar 262 would independently control the boiler circ so that the boiler circ would run either when the Ergomax called for heat or any individual zone pump needs to run?
So far, I haven't lowered the temp to 150 as I think with all zones running, the boiler may not be able to keep inlet temp above 140. I will have to experiment with it.

Ron Schroeder

Dave,

I am confused, do you have an Ergomax or a Phase III as your indirect. The optimal way of pipeing and using their stored heat would be different. Also what size tanks do you have?

Dave_61

Ron,

We originally had a Phase III piped as a separate zone. But our copper tube boiler was shortcycling all the time.
So we just piped an Ergomax E65 (72 gal) tank in series with the boiler to use as a storage tank. Then the supply header to all the zone pumps and the reurn header are piped via 2 closely spaced tees into the return from the Ergomax to the boiler. This summer, we will take the cold water supply to the Phase III and pipe that to the Ergomax and then pipe the output of the Ergomax to the Phase III so that the Phase IIII acts as a 60 gl storage tank (overkill, I know), but we did pay for the Phase III

Joe Brix

Dave

The SR506 has all your thermostats and the Phass III tied in to start each respective circulator. I would check with Taco, but I think the XX terminals are an isolated switch on the 506. I would have the 011's power switched through these XX terminals so that when any circ starts, the 011 will also. You still keep the 011 switched from the boiler's aquastat also so that the 011 will be putting flow through the boiler when the burner is firing. There will be times (like in the summer) when the Ergo will fall below min temp, but no zones are calling and you still need to fire the boiler and have the 011 running to move heat back into the Ergo.

Now you drive the TT terminals on the boiler only from the ErgoMax's aquastat. The buffer tank controls the overall boiler temp of the system.

Now when ever any zone calls for heat (including the indirect) they'll trigger the 011 circ to run. It's when the Ergo drops below it's low limit, it will fire the boiler and the 011 will be running already from a zone, or the boilers aquastat will energize the 011.

hr

If the Ergomax

is going to supply DHW all the time you will need to run that fairly hot. Probably not much below 160 as this is a reverse indirect and depends on hot boiler side continually to offer the DHW via the copper coils inside.

I'm not a fan of a large volume indirect in series with a non condensing boiler. With a heavy heat, or DHW, load that tank could keep that boiler in condensing mode for an extended period. Copper fin boilers REALLY hate cold run conditions. Perhaps a bypass or 3 way thermostatic to protect the boiler.

I noticed that Lochinvar now includs a bypass pump and control on their copper fin boilers.

hot rod

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Dave_61

We actually

have a bypass piped into the system. But since the boiler is so big (300,000 btu) that hasn't been an issue.

Alex Giacomuzzi

Piping.......

Dave:

Your original desire to only have to run the individual heating loop Zone circulator(s) without running the boiler circulator is a great idea, but it is compromised by the present piping connections.

What I mean, if I understand your connection detail above, is when you first tried to run any particular zone circulator and the loop connected into 2 closely spaced T's between the Ergo max and the boiler ----- the water just short circuited between those two closely spaced T's. This was the least resistive path and that is what water will follow. It has nothing to do with whether it can push through another pump or not..... which it could IF it was not short circuiting. The present piping arrangement can not work without the boiler circulator running ---- which is what is happening.

Do you want to run just a zone circulator and heat the zone? If you do then -- Change only one leg of your piping and install the necessary flow check valves. Take the return line from your heating zones (not the supply line to the zones --- it makes a difference) and DHW heater and connect it into the supply line from the boiler going to the Ergo Max. In other words --- you want to put your zones in parallel with the ErgoMax (and actually the boiler).

Now lets talk about installing some flow check valves...
Install one in the return line from the zones which we just moved. Install one on each side of the boiler --- that is right at the boiler side of the two connecting T's that all your zones connect to...... I apologize if this sounds a bit confusing.. These check valves are important to get and keep the water moving where you want it to....

With this piping, your original aquastat in the ErgoMax will control the boiler at what ever temperature your system requires. Since you have such a large boiler and you have bypass piping, cold water return should not be a problem. You will not have to run the boiler circulator. Each zone circulator will circulate water from the ErgoMax to its respective zone. Multiple pumps can run in parallel. The boiler will only turn on when it gets a call from the ErgoMax unless you choose to also have it run on a call from your DHW also....

It is all in the piping....... Your initial ideas on control and operation were very good. Now you just need a couple of piping changes... and flow check valves.

Good Luck....... Alex

Alex Giacomuzzi

Hi Dave

The swing check from your boiler supply should be fine provided it is on the boiler side of the new return T connection.

Regarding the individual check valves in your existing zone pumps circuits ---- these might work fine, but I would either leave space for a flo check or flo control valve (such as a B&G SA Flo Control Valve) or go ahead and install one. You have a relatively high flow between the boiler and the Ergo...... and if one of your check valves is marginal or leaking heat will make it to that circuit.
You can certainly try it without, but if you are repiping you may want to just do it now. Your choice.

I would also add a flo control or flo check valve on the boiler return water side. This may sound like a bit of belt and suspenders (and it is) but you are really close to having your system work the way you want it too. Again your choice on this.

Two flo-control or flow check valves, a T and some piping.
I am excited to hear how it all turns out for you....
I think you will be pleased...........
Regards Alex

Dave_61

Alex,

I sent pictures to your private email address as I wasn't able to post them here.
Dave

gasfolk

Ergomax Tappings

Hi Dave,

Our Ergomax E44 arrived last week, and we're scratching our heads over the tappings to use, so we really appreciate everyone who has commented above.

You seem close to the Siegenthaler piping approach we are considering
"How should I pipe a buffer tank". Ergomax is considering changes to its tank tappings to facilitate this approach.

For now, we plan to bring the T&P and pressure gauge tappings together into a larger pipe for system supply (combined they can transfer a more Btus). Similarly, we will split the system return between the aquastat tapping and a tee into the boiler return. The aquastat, T&P, and pressure gauge will be tee'd off of their respective ports. We understand the warranty will not be voided by this approach.

As homeowners, we would welcome any criticism on this plan.

Glad to see your photos in your other thread, but thought this discussion was quite useful.

Thanks for your thread, Dave.

Best regards,

gf

gasfolk

Ergomax Tappings

Hi Dave,

Our Ergomax E44 arrived last week, and we're scratching our heads over the tappings to use, so we really appreciate everyone who has commented above.

You seem close to the Siegenthaler piping approach we are considering
"How should I pipe a buffer tank". Ergomax is considering changes to its tank tappings to facilitate this approach.

For now, we plan to bring the T&P and pressure gauge tappings together into a larger pipe for system supply (combined they can transfer more Btus). Similarly, we will split the system return between the aquastat tapping and a tee into the boiler return. The aquastat, T&P, and pressure gauge will be tee'd off of their respective ports. We understand the warranty will not be voided by this approach.

As homeowners, we would welcome any criticism on this plan.

Glad to see your photos in your other thread, but thought this discussion was quite useful.

Thanks for your thread, Dave.

Best regards,

gf

Joe Brix

If the T&P tapping

is 1" it might work. If it's only 3/4", I don't think you'll get much flow through the boiler unless it's very small. Dave has a 300K copper tube boiler with 2" supply/return that needs flow. This is why I still think making the tank the primary loop with boiler and loads as secondaries is the only way to make it work.

Ron Schroeder

I don't really like making the tank part of the primary loop and the boiler as a secondary since that puts hot boiler water into the bottom of the tank rather than the top. Piping the boiler into the top of the tank and the boiler return to the bottom will give lower boiler return temperatures for higher efficiency.

gf, where and what size are all of the tappings on the E44? What is your boiler rated output and what is your load?

Ron

Dave_61

Joe,

Here are some pictures of my system....Heatpro (from the boiler room forum) thought that we would rectify the situation of having the boiler pump run whenever any other zone calls for heat by moving return header from house to the tee on the tank where the small air vent presently is. (so it will be teed with boiler supply to tank). This would be a 1.5" connection.
Supply header would remain teed where it is on the boiler return line in middle of first phot.
What do you think? I am trying to get a consensus before paying my plumber to do the repiping. Do you think there would be any issue with flow from house zones into tank when boiler pump is running? All 5 house zones use 007 Taco's. The boiler pump is 0010 Taco.
Actually, pictures would not post, so here is a link with to my post with pictures attached.
http://forums.invision.net/Thread.cfm?CFApp=2&&Message_ID=228912&_#Message228912

Thanks.
Dave

gasfolk

Ergo Tappings

Hi Ron and Joe,

The Ergomax E44 has the following ports:

TOP
1 1/4" for boiler supply
3/4" for pressure gauge
3/4" for T&P

SIDE
3/4" for aquastat
1 1/4" for boiler return (with tee provided for drain)

We were hoping to bring the two 3/4" top ports together into a 1" pipe for better flow. Possible? Our boiler output is 280 MBH, and we estimate a heat loss of 40 to 50 MBH (based on boiler clocking).

Thanks,

gf

gasfolk

Ergo Tappings

Hi Ron and Joe,

The Ergomax E44 has the following ports:

TOP
1 1/4" for boiler supply

3/4" for pressure gauge

3/4" for T&P

SIDE
3/4" for aquastat

1 1/4" for boiler return (with tee provided for drain)

We were hoping to bring the two 3/4" top ports together into a 1" pipe for better flow. Possible? Our boiler output is 280 MBH, and we estimate a heat loss of 40 to 50 MBH (based on boiler clocking).

Thanks,

gf

gasfolk

Ergo Tappings

Hi Ron and Joe,

The Ergomax E44 has the following ports:

TOP

1 1/4" for boiler supply

3/4" for pressure gauge

3/4" for T&P

SIDE

3/4" for aquastat

1 1/4" for boiler return (with tee provided for drain)

We were hoping to bring the two 3/4" top ports together into a 1" pipe for better flow. Possible? Our boiler output is 280 MBH, and we estimate a heat loss of 40 to 50 MBH (based on boiler clocking).

Thanks,

gf

gasfolk

Ergo Tappings

Hi Ron and Joe,

The Ergomax E44 has the following ports:

TOP

1 1/4" for boiler supply

1 1/4" for DHW

3/4" for pressure gauge

3/4" for T&P

SIDE (mid level)

3/4" for aquastat

SIDE (lower)

1 1/4" for boiler return (with tee provided for drain)

1 1/4" for DHW cold supply

We were hoping to bring the two 3/4" top ports together into a 1" pipe for better flow. Possible? Our boiler output is 280 MBH, and we estimate a heat loss of 40 to 50 MBH (based on boiler clocking).

Thanks,

gf

gasfolk

Ergo Tappings

Hi Ron and Joe,

The Ergomax E44 has the following ports:

TOP

1 1/4" for boiler supply

1 1/4" for DHW

3/4" for pressure gauge

3/4" for T&P

SIDE (mid level)

3/4" for aquastat

SIDE (lower)

1 1/4" for boiler return (with tee provided for drain)

1 1/4" for DHW cold supply

We were hoping to bring the two 3/4" top ports together into a 1" pipe for better flow. Possible? Our boiler output is 280 MBH, and we estimate a heat loss of 40 to 50 MBH (based on boiler clocking).

Thanks,

gf

gasfolk

Disclaimer

FWIW, The boiler ports are actually labeled "boiler supply" (on top) and "Boiler return" (at the lower side).

gf

Joe Brix

The E44

is being used for DHW right? So the 1.25" coil tapping are being used for pottable water connections. Again you have a huge boiler with a small load! I assume you plan on feeding the zones from the 2 3/4" top tappings and the returns will share the 1.25 bottom boiler return fitting on the E44 with the boiler's return. The only issue I have is what stops the zone's return from trying to go back into the boiler rather then the E44? I hope you're using zone valves on the heating zone supply pipes.

Joe Brix

Optical illusion?

Is the pipe that tee's off from the supply into the Ergo the bypass? Why does it look like the supply header (has the expansion tank and spiro) comes off the return pipe that comes from the Ergo' bottom return pipe? That doesn't look right to me.

Dave_61

Joe,

The bypass runs between the supply and return for the Ergomax. (bypassing the tank). If we ever had an issue with boiler water being too cold for inlet, we could crack the bypass open a bit. Currently it is closed and we have no problems.

We originally had the supply header teed off the boiler supply to the Ergomax (where bypass is presently). The boiler pump was actually pushing hot water through all the separate zones, including the Phase III. I spoke with Adam at ERrgomax and he recommended the present piping situation with both the supply and return headers teed next to each other off the boiler return.. However, this means the boiler circ must run whenever any zone pump calls for heat, as the water would otherwise shortcircuit between supply and return headers.

The easiest recommendation I have gotten is to simply take the return header and tee it into the tank next to the bypass. there is currently an air vent on the tee. Then the boiler circ would only run when the Ergomax calls for heat.
My only concern is that we would have a problem with flow from the return header into the tank when the 0010 boiler circ runs. Again, all zone pumps are 007's with flo-chek checkvalves just downstream of each pump.

What do you think? I realize it's not the perfect cure, but do you think it will work?
Dave

Joe Brix

Yup

If you're telling me the supply header is tee'd in right next to the return header, yes moving the return header up the the supply line of the ErgoMax should help.

I see you didn't pipe in the Ergo's coil to the Phase III yet correct? You might not need it. It would make for a great heat exchanger for a snow melt, pool heater or solar hot water panel to feed into your hydronic system. Just a thought.

gasfolk

Good question

Hi Joe,

We don't know the answer. We figuredthat pumping out the top and to the return at the bottom, the path of least resistance would be through the Ergomax. (Siegenthaler's October 2001 article) shows a few check valves. Are more indicated? Has Siegenthaler moved away from this piping scheme?

Actually, our current plan is to use injection piping between the E44 and our supply loop. Flow through the the injection return should be much less than the boiler return flow, perhaps protecting the boiler from thermal shock?

Thanks again for your suggestions, Joe.

gf

gasfolk

Good question

Hi Joe,

We don't know the answer. We figuredthat pumping out the top and to the return at the bottom, the path of least resistance would be through the Ergomax. Siegenthaler's October 2001 article shows a different schematic from those we've seen elsewhere. It does include a few check valves. Are more indicated? His later articles show primary-loop buffer and boiler as secondary, so has Siegenthaler moved away from this piping scheme?

Actually, our current plan is to use injection piping between the E44 and our supply loop. Flow through the the injection return should be much less than the boiler return flow, perhaps protecting the boiler from thermal shock?

Thanks again for your suggestions, Joe.

gf

gasfolk

Good question

Hi Joe,

We don't know the answer. We figuredthat pumping out the top and to the return at the bottom, the path of least resistance would be through the Ergomax. Siegenthaler's October 2001 article shows a different schematic from those we've seen elsewhere. It does include a few check valves. Are more indicated? His later articles show primary-loop buffer and boiler as secondary, so has Siegenthaler moved away from this piping scheme?

Our plan is to make injection piping between the E44 and our supply loop. Flow through the the injection return should be much less than the boiler return flow, perhaps protecting the boiler from thermal shock? If not, we can split the injection return and send half through the aquastat port.

Thanks again for your suggestions, Joe.

gf

gasfolk

Good question

Hi Joe,

We don't know the answer. We figured that pumping out the top and to the return at the bottom, the path of least resistance would be through the Ergomax. Siegenthaler's October 2001 article shows a schematic different from those we've seen elsewhere. It does include a few check valves. Are more indicated? His later articles show primary-loop buffer and boiler as secondary, so has Siegenthaler moved away from this piping scheme?

Our plan is to make injection piping between the E44 and our supply loop. Flow through the the injection return should be much less than the boiler return flow, perhaps protecting the boiler from thermal shock? If not, we can split the injection return and send half through the aquastat port.

Thanks again for your suggestions, Joe.

gf

Dave_61

That's what

we will be doing. Moving return header up to boiler supply to Ergomax. My only worry is that the boiler pump (0010) would overwhelm individual zone pumps (007's) and not allow flow into tank when boiler pump is operating. Do you think that will be an issue?
We plan to pipe Ergomax this spring to preheat hot water for Phase III and then maybe open a carwash!
Dave

gasfolk

If the hottest water is at the top...

of the Ergomax, would your efficiency benefit from taking the supply header off the top and piping the return header to the bottom? Sigienthaler recommended this in his October 2001 article, but if you have contrary evidence, we'd like to know before we pipe our E44 this spring.

Thanks,

gf

Joe Brix

Problem with Dave's setup

He was getting ghost flow. The large 010 pump was also pushing hot water through the zone circulators and flow checks since the zones' supply header was just Tee'd off the supply comming from the boiler. That's why I'd prefer zone valves. If you're using the T&P and guage ports for the heating zones you're helping to make the buffer tank the primary and isolating the boiler and heating zones as seperate secondary zones.

gf: what kind of boiler are you using? 280K sounds way oversized and what are the return/supply piping sizes?
How many heating zones are you running? Will the E44 supply the DHW?

gasfolk

Hi Joe,

WM EGH-85, 350 MBH input, 280 MBH output, 243 MBH Net I=B=R.

EGH-85 Tappings: Supply two 3", Return two 2 1/2".

Zones: Two small RFH (master bath and kitchen), and one whole house gravity conversion (paired NE and SW supplies and returns--could be two zones, but controlled by one thermostat).

Boiler clocking gives a heat loss of about 40 MBH, MJ8 gives 90 MBH. Yes, DHW from the E44.

Thanks,

gf