Mod CON? Or Power vent 85%?

Suzook

^ Well now looking at the updated diagram, it looks like the expansion tank on the ind HW heater is not necessary...as technically, both the boiler and ind HW heater are sharing the tank...no?? Sorry for all the questions, but I have learned ALOT here, and really appreciate it!

NY_Rob

If you use the diagram on the previous page... the expansion tank covers both circuits.
From your previous posts, I got the impression your plumber also wanted to install a high pressure potable water expansion tank on the DHW side of the indirect? Two different tanks, one low pressure (12-15psi) tank on the closed loop system and a high pressure expansion tank (70+ PSI) for potable household water?

At any rate, you only need one low pressure exp. tank for the closed loop side even if you use the factory diagram.

I made one other change to the factory diagram in addition to routing the spaceheating and indirect supply through the Dirtmag... I installed the indirect circulator (3-speed Grundfoss) on the supply side of the indirect vs. the factory diagram showing it on the return side of the tank. I figured that placing it on the supply side would always keep with "pumping away" from the expansion tank vs. pumping in to the exp. tank.

Updated diagram below.....

Suzook

^ Thanks, I really need to buy you a couple of drinks. You have been a BIG help!

NY_Rob

^ only if it works.... lol

I had a lot of help from Hatterasguy (and others) when I was setting my system up. Never hurts to pay it forward

Suzook

^ Another question (add it to my tab) I can feed HW heater off top, and heat off bottom of boiler if I want?? I'm assuming so.

NY_Rob

Yeah, makes no difference- top or bottom feed or return or both or two supply's one return, etc.... mix and match to your hearts content. Try to have the supply water always passing through the Dirtmag though.


If it makes you feel better... I had the same question before designing the layout for my system. I called HTP to be sure.
I have a single supply off the bottom but top return for spaceheating and bottom return for the indirect.

Suzook

^ Thanks. Well not a lot happened this weekend. Kind of sick. What I did get done was all piping is out of the slab from original boiler location, and ran to new boiler location. I was gonna pop the concentric vent through the wall, and plumb the pvc pipe from boiler to it, but just not feeling well today. Slowly but surely, its coming together.

Suzook

Should I be concerned with snow blocking the concentric vent coming through the roof? I have about a 35 to 45 degree pitched roof, and will be bringing vent thru roof. I would say it will be about 3 feet above the roof line when its done.
Or should I just vent it through a side wall??

NY_Rob

3' above the roof seems like enough for around here... in most cases. On my house, certain roof areas are prone to drifting... you are no doubt familiar with your roof area where you plan to install the vent. Make sure it's not one of those "problem areas".

FWIW- My boiler tech recommended against the concentric vents- he told me he has had some problems with them over time (exhaust air was leaking into the combustion air on one and caused a mini-explosion). He said we can use it, but he really wasn't too happy about it. He's is a very conservative guy, but he's got a lot of experience so I went with his advice on the venting and went with two-pipe conventional venting.

Suzook

Well, just to be safe, I side vented through a wall. I did use the concentric though...hopefully i dont blow up I will make sure the vent is glued properly.

NY_Rob

Any updates?

Hope you didn't blow up

JUGHNE

Question for all using concentric vent:
Do you glue the outside cone on permanently?

Others have said that if not glued that condensate can dribble thru that unsealed joint and frost over the intake.

I use silicone caulk for that joint to be water tight and a couple SS screws to hold it in place. This is for the rare occasion where you may have to remove the cone for cleaning or inspecting the inlet (outer) pipe.

Or any comments on this method.......

Suzook

NY_Rob said:

Any updates?

Hope you didn't blow up

LOL...Well life got in the way for a few weeks. Heres some pics. Plumbing is done, need to wire up circs, zone valves, hook up condensate...and schedule inspection.

Gordy

And support the x tank.

Suzook

^funny you mentioned that, was supposed to do it before, and completely forgot.

NY_Rob

I wonder how well the Dirtmag will work as a micro-bubble eliminator with pumping in to it?
Caleffi recommends "....should preferably be installed after the boiler, on the pump suction side, as this is where most of the micro-bubbles form."

Any reason he (the installer) located the expansion tank on the return? You're pumping in to the expansion tank vs. away from it with that arrangement.

Gordy

Yes the dirt mag should be aft of the circ, and the xtank also. There is room to do that. The manual also shows it as such.

hot_rod

The very best air removal is at the hottest spot, and the lowest pressure point.

You are at a hot point, right off the boiler supply, no problem.

With the expansion on the return before the boiler that becomes the PONPC, if it has a low pressure drop thru the boiler, in theory the pump is pumping away from the PONPC, as it would on a hydro separator with expansion on the return side.
A gauge on the discharge side of the circulator would show if pressure increases from static fill when the pump fires. Get one of this hose connection gauges, screw it on the drain cock below the DiscalDirt Sep and see what it reads when the pump is off, and then pump on.

I think it will work fine located as is for all 3 functions air, dirt, magnetic.

It's really the coalescing media inside that does all the work so not as location critical like a scoop purger.

Suzook

NY_Rob said:

I wonder how well the Dirtmag will work as a micro-bubble eliminator with pumping in to it?
Caleffi recommends "....should preferably be installed after the boiler, on the pump suction side, as this is where most of the micro-bubbles form."

Any reason he (the installer) located the expansion tank on the return? You're pumping in to the expansion tank vs. away from it with that arrangement.

No idea. Is it really a big deal? Im so done with this project. What issues can I have with this setup? I sort of agree with hot rod about where the expansion tank is. Let's think about it, it's at the very end of the loop, and more than likely PONPC. Is it really that much difference if it's just on the other side of the boiler?

Gordy

Depends on how much head is between the xtank, and the inlet of the circ. Yes that boiler has a low pressure drop, but it still has one.

My point is there is a manual with illustrations of component locations. I see no problem for room in being able to follow those to do so.

Will it all work? Probably be fine. Seen many that don't pump away that work fine. Is it proper no. Like hot rod said at least the sep is on the supply side. However being on the suction side of the circ would allow it to do a better job faster. Air comes out of solution at lower pressure. So by being on the inlet side of the circ the sep sees lower pressure than the discharge side of the circ.

NY_Rob

The reason I asked "Any reason he (the installer) located the expansion tank on the return?" was because he (the installer) had plenty of room to locate and pipe the exp tank into the supply side before the pump- which is common practice nowadays. Even the HTP manual shows the exp tank on the supply side... wondering why he went against the boiler manufacturer's recommendations when it would have no problem to pipe it the other way?

Same with the Dirtmag... Caleffi clearly states in the manual "...should preferably be installed after the boiler, on the pump suction side" and it could have easily been done because it requires the same amount of space if you flip the Dirtmag/Alpha around horizontally. Again, he went against the device manufacturers recommendation where it would have been no more effort to pipe it in accordance to recommendations?

At any rate... it can all be easily corrected if it proves problematic once you fire it up, it's just surprising to see a new install setup in a contradictory fashion.

Suzook

^well, I have ZERO knowledge, and he apparently does not either. It's his 1st mod con, so it's a learning process. He's old school plumber and I guess it shows. I appreciate all of your knowledge and help. BTW, question on wiring tstats. I'm looking at you diagram for a few pages back. I currently have no cwire, but will be adding new thermstats that require a cwire. Luckily, my house is wired with 3 wires to the stats already. So just wire it up like your diagram? Should have a constant 24v for the "c"wire??

NY_Rob

This diagram?


Yes, that is for "C" wire T-stats.
The xformer is always hot- so you'd always have 24vac between the red and blue wires.


How did you do with mounting the ODR sensor?
Mine was a PITA because the boiler is at the extreme south end of the house and the ODR needed to get mounted at the extreme north end of the house (up near the peak of the roof too).

Suzook

^ Yes, that diagram. Fortunately it's about 20 feet away from the boiler. BTW, see my pressure relief valve?? Could I t off that, and put expansion tank and relif valve there? Just grasping for straws. Thanks

NY_Rob

^Physically it would work, IDK if code lets you share the pressure relief line with anything else or if that's even an issue?
One of the Pro's will have to answer that....

Suzook

^ I will leave it as is, and see how it works....ok, so I'm an ****....wiring my honeywell zone valves....so tI figured out, and hooked up mt 1st floor zone, its working when i call for heat, I hear it open. My 2nd floor has a 2 wire hookup with a common from another source. I hooked that zone up without the c. I have both the motor wires connected to the w wire going to the stat and the other 2 going to r on trans..that make sense?

Trying to wire up the indirect. The circ is obvious. Well what about the aquastat? That gets wired directly to line voltage??? Or does it operate low voltage connected to boiler terminal marked hw sensor? I thought that was for a compatible htp ihw heater? How does the boiler know when to fire to heat the water. What am I missing?

Where did everyone go???

NY_Rob

Better if you post a wiring diagram of your t-stats... easier to understand.
******************************************
The aquastat closure leads connect to the "DHW TEMP SENSOR" terminals on the low-voltage terminal strip at the boiler.

To use an aquastat vs. a temp sensor you need to go to item 39:SA in the installer menu and select and save "Aquastat".

Post the make and model # of your aquastat just to be sure....

Suzook

^ You are a life saver! I thought it might wire up like that, but was a bit confused.

NY_Rob

Happy to help....

There's quite a few adjustments that you'll probably need to make in the installer menu. Unfortunately some of the default settings are at odds with a zone valve install (like a 1-min post purge on the CH pump.... with the zone valves closed!) so adjustments need to be made to prevent damage to components. I can help with the installer menu when you're ready.

Suzook

^Yikes, your not kidding! So all zone valves hooked up, IHW hooked up, last thing is getting the condensate drain hooked up. Hoping another week for my inspection, and meter install.

Suzook

NY_Rob said:

Happy to help....

There's quite a few adjustments that you'll probably need to make in the installer menu. Unfortunately some of the default settings are at odds with a zone valve install (like a 1-min post purge on the CH pump.... with the zone valves closed!) so adjustments need to be made to prevent damage to components. I can help with the installer menu when you're ready.

Ok, so gas pressure test set for this Tuesday, then meter install next Friday. Wondering what settings I should play around with in the mean time? Thanks.

NY_Rob

^ I would start by trying to plot your reset curve based on your home's heatloss and radiation using a design day value of 15F for our area and a 65F indoor temp.

Most of the other install option values are pretty straightforward, but a properly setup reset curve is vital to efficiency and comfort and may take a while to perfect (if that can be done).
I found using excel was really helpful comparing candidate reset curves...

Suzook

So it sounds like after Nat grid places the meter, they will want me to fire up the boiler so they can check lockup and running pressure. What settings in installer menu should I set? I have aquastat set for indhw, where is setting for post purge?

NY_Rob

Item 20:PE is the CH pump post purge entry.
Unfortunately it's defaulted to 1min... set it to 0min for use with zone valves otherwise you'll deadhead the pump.

23:Pr is the DHW pump post purge entry... you can leave it at it's default of 1min.

NY_Rob

Our setups are fairly similar, I can scan in the install menu pages with my own settings penned in if you think it would be helpful?

Did you or your installer do a heatloss analysis on your house?
We need the overall BTU/hr loss at DD temp to start working on the ODR curve.

Gordy

If you "want" to understand the capabilities of your appliance read, and understand the I/O manual.

Suzook

NY_Rob said:

Item 20:PE is the CH pump post purge entry.
Unfortunately it's defaulted to 1min... set it to 0min for use with zone valves otherwise you'll deadhead the pump.

23:Pr is the DHW pump post purge entry... you can leave it at it's default of 1min.

Thanks

NY_Rob said:

Our setups are fairly similar, I can scan in the install menu pages with my own settings penned in if you think it would be helpful?

Did you or your installer do a heatloss analysis on your house?
We need the overall BTU/hr loss at DD temp to start working on the ODR curve.

That would be VERY helpful. Yes, 65k heatloss.

Gordy said:

If you "want" to understand the capabilities of your appliance read, and understand the I/O manual.

I read it numerous times, some things I just dont understand....Hence the reason I am here.

NY_Rob

65K BTU heatloss at 15F doesn't sound right...
What's your heated sqft?

Suzook

2200

NY_Rob

65K BTU's for a 2,200 sqft area works out to about 30BTU's/sqft.

I got this from Dana Dorsett from Green Building Advisor when I was first looking i to replacing my old system last year...

******************************************************
"It's better to NOT use xxBTU per square foot as a rule of thumb, but keep it in mind for sanity-checking other estimation methods.

For NY/NJ and southern New England for a 2x4 framed house 15 BTU/ft is somewhere near the middle of the bell curve, but its' a fat middle, and there are the exceptions that are truly north of 25 BTU/ft @ +15F, usually small houses with lots of window area, and an uninsulated foundation.

When discussing it with contractors present the fuel-use calculated number first stating that its based on weather & fuel use data, then if they protest point out that it's still 20 BTU per foot, which is a typical real-world number for code min houses in Anchorage AK (at -9F!)."
*******************************************************

After doing the calculations with my actual gas usage for a year, our local HDD's and my heated square footage... his "15 BTU/ft is somewhere near the middle of the bell curve" statement was pretty darn accurate as my house came in at 15.37 BTU/ft with a 50 deg rise at 15F DD.

The whole idea is to get your heating output to closely match your heating loss with the correct supply water temp, not to simply blast overly hot water through the radiators and cycle the boiler on/off many times per day. If your heatloss figure is not accurate the ODR curve won't match actual heatloss and efficiency will be out the window.

To illustrate the difference between supply water temps on a 2,200 sqft home with a 30BTU/ft heatloss and even a 20BTU/ft heatloss look at the calculations below:

You have 150ft of fintube right?
-To get 65,000 BTU's (at 30k BTU/ft heatloss) out of 150' of fintube you need 170F SWT (160F AWT).
-To get 44,000 BTU's (at 20k BTU/ft heatloss) out of 150' of fintube you need 145F SWT (135F AWT).

The ODR curves between the two SWT examples above will be drastically different. One will be in condensing mode for much of the heating season, the other won't.