Hydronic replace old boiler-gravity conv-2 pipe- Near Boiler piping and bypass?

OldawgBryant

New to the wall, but have been searching through all the comments and topics & read all of Dan's (and some other) books also. After 97 years the original Bryant boiler is being "retired." Probably could have gone to 100, but I've had the place for 17 years and never fired more than 140deg (else things would make a lot of noise). Used to take about 1-1/2 Hrs to get house up to decent temp (say from 50's to high 60's), but all even and no real issues. Except condensation and Rust. House was orig gravity fed system, then at some point a B&G series 100 was added (on the return, of course). When I got it, I switched the overhead expansion with a Amtrol#30, switched back flow/fill and swapped a Red Baron from the B&G and moved a couple of pipes (switching black for copper) & added a Modine in the attached garage with a 007 pump. Now it's time to move-on.

1) Old system 1926 Bryant 4-26 90,000 BTU-GAS-fired; 2 pipe system Existing "Gurney" cast-iron radiators total 47,260 BTU-of radiation (278 sqft) +/- 60 gals of water in system
2) Current Heat loss for 1k sqft 1story Bungalow= 44,577 BTU/HR (house only) + garage = 56,313 BTU/HR total
3) New boiler= Burnham Series-2 #204E- 103,000BTU/hr
4) 2 zones (main house & garage) & room for 2 future zones (manifold)
My questions are:
1) Should I pipe-in a Bypass with a temp sensor & pump (like Burnham offers in their manual)? I have never run the system above 140deg and, I am concerned about condensation and the amount of water in the system
2) What size near boiler piping should i use? New pump will be a TACO 0010, pumping away from expansion tank (same tank) with a Spirovent and the fill will be connected between tank & vent; The burnham has 1-1/4" for input/output & I have 2 radiators that have 1-1/4" inputs/outputs and the rest of the house ends in 1-1/2" supply returns. The other zones will be 3/4" from a manifold. All piping is black pipe.
I planned to go 1-1/4" black pipe from the boiler to the manifold, but not sure if I should continue with 1-1/4" copper to the main supply/returns or reduce so the circulator (TACO-0010) has enough resistance (after reading Dan's book "How Come?")
3) How would you folks (who know a lot more than me) out there lay-out the near boiler piping? ***note: the boiler is positioned where it is due to extreme space limitations (though the sketches look wide-open there is hardly any space) Everything wants to be hung from the ceiling and a tight perimeter needs to be kept around the boiler.

Danny Scully

So, is the total heat loss 56,313? 

OldawgBryant

yes, counting the garage (that is the most insulated room!) I don't run heat in the garage much, though. I used the Slant-Fin app on the phone to do the calcs, but was surprised when comparing to the radiation that exists.

hot_rod

Did you buy the new boiler yet? It is a bit large, almost twice what you need at design. That could lead to short cycling As you are at design for maybe 10% of the  year

Danny Scully

This is where I was heading. Why such a big boiler? 

OldawgBryant

I bought it last December, when water was leaking out of the old one, so I didn't have the time or knowledge to do any heat loss calcs as I thought I would be replacing it and it was close to what was there 103MBH vs 90 MBH. I do see the spec says 87MBH dor DOE heating capacity. What does that mean? do you go by the 103 MBH for input or the 87 for DOE MBH?
Anyway I can't take it back, so I want to try to use it. Since this system has a lot of water and it may be oversized (but I could ad zones in the future) should i keep 1-1/4" near piping?

OldawgBryant

I was just reading something from "EdTheHeaterMan":
"Boilers have 3 of these numbers. Input is for sizing the gas pipe or nozzle, output is based on the efficiency as in a furnace, and NET is what you use for selecting radiator size based on the Heat Loss Calculation. The numbers are actually called Gross Input, DOE Output and AHRI NET (formerly I=B=R NET). Once you determine the Heat Loss of a building, then you select the amount of radiation and then the boiler based on the NET BTUh number. "
So, this Burnham lists 76,000 BTU/H, so the oversize is getting less. I was confusing the Input of 103 (MBH)...

OldawgBryant

@hot_rod Yeah so, will that Caleffi mixing valve work with my planned system? I think I am oversized, but maybe not by a ton... But with the gravity conversion I am concerned about condensation protection. I only have 2 zones now and maybe a couple more later on (which may fix that over-sizing) Thanks for your time (I am a G.C. not a plumbing contractor)

hot_rod

OldawgBryant said:

@hot_rod Yeah so, will that Caleffi mixing valve work with my planned system? I think I am oversized, but maybe not by a ton... But with the gravity conversion I am concerned about condensation protection. I only have 2 zones now and maybe a couple more later on (which may fix that over-sizing) Thanks for your time (I am a G.C. not a plumbing contractor)

Yes the 580 is made just for that application, high mass systems with non condensing boilers of any type.

Bypass piping or pumps can work under certain conditions. But if they only had a brain

https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Caleffi-280976A-Product Overview.pdf

mattmia2

The mass of the system will work in your favor, it will give the over sized boiler something to heat. You will have to be careful that the thermostat turns it off well before it hits setpoint so that it won't overshoot as all that mass continues to emit heat for say another half hour.

OldawgBryant

@hot_rod I like the looks of this valve, but I don't like the installation drawing. What happened to "pumping away?"
Can't I just install it in place of the Burnham recommended manual valves? 1-1/4"

hot_rod

With any type of thermostatic 3 port mixing valve you should always pump from the mix port. This pulls flow from the H and C port to mix properly

The schematic shows the pump and expansion tank downstream from the mix port of the 280

The distribution circs see the tank ponpc thru the 280 valve and they are also pumping away. So hydraulicly speaking it works.

OldawgBryant

@hot_rod This looks like a Primary/Secondary system?
1)Do I need to get more complicated with the simple cast-iron boiler? I have mainly 1 zone with 6 radiators on it. I may have some future stuff and the garage zone, but I really don't heat the garage much. With this setup,now there's a hydro separator and 2nd pump... Do I need the P/S system? I can see that it is still pumping away, but can it be done with only 1 pump?
2)Why does the cold input water get added after the mixing? that seems like it would defeat the purpose (even though the system should not really be adding any water as a closed system)
3) It appears there are more 1" mixing valves in stock than 1-1/4" (the Rep "Dan Davis" said they use the 1-1/4" more for solar systems and that most places don't stock the 1-1/4 they would have to order it, but I found a couple of 1" ones on the shelf) would the system head pressure suffer by reducing to 1" from 1-1/4"?
Thanks for you time

OldawgBryant

hot_rod

The 1" has a 10 Cv, so easily moves 10- 12 gpm. I think your system need 6- 7 gpm.
I'd go with a multiple speed circ. i think a 15-58 or equal on speed 2 would do it. You have one more speed if you add on some additional radiation.

Assuming you are talking radiators or fin tube? No small tubing circuits? Low pressure drop cast boiler? A single temperature system.
.
Low temperature radiant would need another pump, mix valve, etc. Then I might go P/S piping.

If you order one, go with the 130° sensor.
280165A NPT union
280965A is 1" sweat union

OldawgBryant

Yep, big ol' cast-iron works of art, no slant fin. Simple single temp system, no radiant. As I say occasionally I'll fire-up the Modine in the garage (if I have to work on something and it's really cold.
I was looking at the 165A NPT
Low pressure drop on the boiler? hmmm. not sure about that.... Burnham 204E cast iron. I think the relief valve is 30psi, there's a good amount of piping in the system and I was going with 1-1/4" near boiler piping and tying right into the old cast iron runs.
I think the amtrol #30 has 12# pressure

OldawgBryant

I think I Calculated the flow to be 8.37 gpm MAX

OldawgBryant

your drawing was what I was envisioning. I'm also going to test the tap water and see about installing a filter for contamination. After 17 years, I looked at the fill screen on my WATTS and it was full of crud. What about any gauges? it looks like it can take a temp/pressure gauge?

OldawgBryant

@hot_rod what if I moved the pump right after the expo but before the mixer?

hot_rod

Yes that boiler is a low- no pressure drop vessel.

Here is a good option to still pump away from the mix port on the valve and also away from the exp tank.

It puts the tank in a bit cooler fluid also.

I'd look into one of these fill cartridges on the line. It will grab particles and also deionize the fill water.

https://axiomind.com/axiom_products_cat/h2o-demineralizer/

Fill and pressure test with your water, but don't fire the boiler. Drain it completely out, then fill with the cartridge. No sense in dumping the treated water down the drain while checking for leaks. Of course you won't have leaks, but...:)

The minerals will not separate out of the fill water until heat is applied.

I like to run the boiler hot, 180F or more for and hour. This will drive all the air out of the system if you have a good air sep, you should be done.

I still believe the hydronic conditioners add value also.
You get O2 scavengers, film providers, balance the low ph DI water, and some lubricant for the pump moving parts. Get the squirt cans and add it after everything checks out.

OldawgBryant

@hot_rod Thank you sir. I want to be pumping away, for sure. The original set-up had the tank on the supply and the pump on the return. Although supply/return lines are 1-1/4" will reducing to 1" for the bypass (and thus the main return) be a problem? Or, like you said, a variable speed pump can solve any issues (On the old system, the return Red Baron was 1", but the old cast iron boiler was probably a lot thicker and held more water)


I was also thinking doesn't Caleffi make some kind of water rust magnet filter?

hot_rod

There is a special going in now for this kit
Various sizes and connections
Air sep and DirtMag

jesmed1

OldawgBryant said:

I bought it last December, when water was leaking out of the old one, so I didn't have the time or knowledge to do any heat loss calcs as I thought I would be replacing it and it was close to what was there 103MBH vs 90 MBH. I do see the spec says 87MBH dor DOE heating capacity. What does that mean? do you go by the 103 MBH for input or the 87 for DOE MBH?
Anyway I can't take it back, so I want to try to use it. Since this system has a lot of water and it may be oversized (but I could ad zones in the future) should i keep 1-1/4" near piping?

We have two way-oversize oil hot water boilers in our 4800 sq ft 4-unit condo building. When I first moved in and started checking the heating system, I found the boilers were short cycling, with the result that not enough heat was reaching the second floor units. There were multiple problems all contributing to the short cycling, but the most obvious was that whoever installed the thermostats had left the swing settings on the factory presets for forced air heat. I think the swing setting was 0.2 degrees.

After fixing the other problems, I experimented with the swing settings and found that 0.5 or 0.75 degree swings let the boilers run long enough to get the water temperature up and get heat to the second floor units without short cycling.

So I suggest making sure your thermostat has adjustable swing settings (some don't) and finding the optimum setting to prevent short cycling. It won't fully make up for the fact that your boiler is oversize, but it will help.

EdTheHeaterMan

You left this query on another discussion:

OldawgBryant said:

@EdTheHeaterMan I am doing kind of a similar thing, but not messing with the supply/return for the radiators, only replacing the boiler & connecting to the piping. I've done the heat loss etc, and I'm just trying to figure-out how to size my near boiler piping and connect it to the old system. Most of it is 1-1/4" (coming out of the new boiler) and serving the existing house. What happens if you drop-down to 1" in between? Should I be doing a head loss calc for all the existing piping so my boiler gpm does not suffer?

I thought I would answer it here where you might find it easier

I would direct you to this publication: https://s3.amazonaws.com/s3.supplyhouse.com/product_files/108119-Reference Guide.pdf
I used this to teach a one day seminar on Hydronics. The first 4 pages of the text (3,4,5 & 6) give you the information you need for selecting the correct pipe size for your system. @EBEBRATT-Ed has the info in the previous post but the book gives you the reason why those pipe sizes are what they are. It will also have more info to answer some of your other queries that you have been discussing with hot_rod Bob Rhor From Califfe

To be clear... Pumping Away means pumping away from the expansion tank in order to add the pump's head pressure to the system. Sometimes that will be on the return based on the nature of your system. Since you are using the mixing valve to insure a minimum return water temperature to the cast iron boiler you may need to give up some features in order to accommodate more important features. @hot_rod has more experience on this topic, he will not steer you wrong.

EdTheHeaterMan

To be more specific to your system, I understand it is oversized and you are stuck with it. I also understand you are going to add more load in the future. With that info, I would use 1-1/4" near boiler piping with Tee fittings that are valved off for future use. You may use 1-1/4 x 1" tee fittings or you may use 1-1/4" x 3/4" tee fittings based on what the future may hold. You need to do the math to determine the BTUh capacity of each existing branch and/or future branch off the boiler main supply and return piping. Then select the pipe size accordingly.

Hope you find this info as clear as mud.

Mr.Ed

OldawgBryant

@EdTheHeaterMan Thank you sir! I am going with the 1-1/4" for the main house and then a manifold of 3/4 for garage and future. Most of the near boiler will be steel, but there will be some copper. That B&G book was also very good. I have ordered the Caleffi 1-1/4" mixing valve for the boiler protection, The dirt Mag will be 1" sweat, but I don't think that 1" at that point will hopefully make much of a flow or head difference. I have learned a lot in these weeks on the board, and after reading all of Dan's Books and I am more confident (which could be scary). The toughest thing is the actual piping (more steel than copper) because of the space limitations (I am trying to maintain as small a footprint as possible) even though the basement is wide-open and there will be no shortage of combustion air.
I'm using a Spirovent, so I can keep things tight for the venting. The hardest most time-consuming is the piping and getting everything neat and plumb/level. I am worried about threaded leaks, but I will use the tape + mega on the joints.

mattmia2

I would order the dirtmag in npt and use adapters on the copper pipe because it is a very big chunk of brass and a little tricky to sweat and very expensive if you destroy it in the process.

EdTheHeaterMan

OldawgBryant said:

@EdTheHeaterMan Thank you sir! I am going with the 1-1/4" for the main house and then a manifold of 3/4 for garage and future. Most of the near boiler will be steel, but there will be some copper. That B&G book was also very good. I have ordered the Caleffi 1-1/4" mixing valve for the boiler protection, The dirt Mag will be 1" sweat, but I don't think that 1" at that point will hopefully make much of a flow or head difference. I have learned a lot in these weeks on the board, and after reading all of Dan's Books and I am more confident (which could be scary). The toughest thing is the actual piping (more steel than copper) because of the space limitations (I am trying to maintain as small a footprint as possible) even though the basement is wide-open and there will be no shortage of combustion air.
I'm using a Spirovent, so I can keep things tight for the venting. The hardest most time-consuming is the piping and getting everything neat and plumb/level. I am worried about threaded leaks, but I will use the tape + mega on the joints.

Will the dirt mag handle all the flow with all zones calling for heat. All I can say is the a chain is as strong as its weakest link.

Case in point. My first water chiller system I ever installed, I had no clue... So I asked someone to help me with the design. He worked on government projects 10 times larger than this hotel I was designing. Since the chiller was going to be on the roof and and the Hotel owner did not want to drain it in the winter, We designed everything based on the specific gravity of 40% Glycol. Pipes, Pumps and valves were all designed slightly larger for the project. Once we were done I pumped two 55 gallon drums of Glycol into the system. Then we filled the rest with water. A specific gravity test indicated that we were near 50% Glycol, And I thought that would be just fine. Over time with repairs and the like we would be at 40% within a few years.

We started the chiller and the air conditioners worked fine at 85°F outside. When it got to 90°F outside, the air handlers in the rooms would not keep up. I went over the calculations with my friend only to find that all that extra large pipe and pumps were all for naught. There was one thing that was overlooked in the sizing, There was one section of the design where we did not account for the different specific gravity of the water in the system. I cant remember exactly what it was, but it was not an easy fix. That was my weakest link… We had to dump the antifreeze and run water only… after we did that the cooling system worked perfectly. I had to bite the bullet and eat the antifreeze. I also had to give him a huge discount because from now on, the chiller would need to be drained every winter.

So, All I’m saying is that a 1-¼” Dirt Mag might cost more than a 1”, but if you have insufficient heat when the temperature drops below 15° F in the middle of the winter… Well lets just say this… when you ask the folks on HeatingHelp.com why you get no heat below 15°… Don't’ get angry if "I say I told you so".

hot_rod

Very little pressure drop in a DirtMag, that is why the bell is such a large diameter to keep the pressure drop low as it flows thru.
It is called a low velocity zone. Slow the fluid velocity as it crosses the bell. Air and dirt come out as you slow the speed of the fluid. The media does the rest of the work

Ramp type air purgers use the same idea, increase the diameter of the scoop to lower velocity. Air rises up to the auto vent.

I believe the bell is the same on 3/4, 1 and 1-1/4 DirtMags, just the pipe connection changes for connivence

You will see the same with zone valves, if it is an 8 Cv it could have a 3/4, 1, or 1-1/4 connection, flow and pressure drop will be the same. Just the hole size changes😗



Same concept at play in air scoops

EdTheHeaterMan

@hot_rod, I don't doubt you on this

I only bring up the 1" v. the 1-1/4 because that indicates the size of the piping that it is connected to. If you have a 1-1/4" supply manifold with all the 1/2", 3/4" and 1" take offs out to the system but create a 1" return manifold into a 1" Dirt Mag with a 1" return pipe to the boiler, then all that shared piping will have a higher velocity to move the GPM of the supply, until it slows down in the larger area of the Dirt Mag. This 1" Shared piping may even restrict the total GPM of the whole system... therefor it is now the weakest link. Not the Dirt Mag. All the pipes on either side of it.

I believe that if one was to use a 1-1/4 return manifold and a 1-1/4 Dirt Mag then return to the boiler with a 1-1/4 pipe, you could get almost the same performance if one was to use a 1-1/4 return manifold and a 1-1/4 x 1" reducer and close nipple to a 1" Dirt Mag then do the same on the other side then return to the boiler with a 1-1/4 pipe. The close nipples would not offer much pressure drop. The 1" manifold and other return piping might make a measurable difference.

Don't you agree?

OldawgBryant

@EdTheHeaterMan @hot_rod That's kind of what I'm doing. Nobody had the 1.25" Dirt Mag in stock, but I found the 1" sweat, so that is the only point of 1" and I was going to use 1" unions and iso valves also, so the 1" dirtmag line between 1.25" return would be around 12"-16" +/- long between the 1.25" returns (just for the dirt mag). Of course, the possibility of destruction when I sweat it makes me concerned (I've sweat a lot of pipe and brass fittings, but nothing t like this...)
But if the mass of the dirt mag is designed to slow the flow, then the reducing to 1" kind of works against that also? Mmmmmm Maybe I should try to return that one and order the 1.25" NPT version...
I am pumping to the return (still away from expansion)...

hot_rod

It will look odd with reducers on both ends but the function will not be affected.
Any idea of what flow rates you may be running?

mattmia2

supplyhouse.com has a lot of stuff that shows as out of stock that suddenly they find one in a day or 2 when you order it.

OldawgBryant

@hot_rod 8.7 Max, probably around 8 GPM. I want to do a calculation for the system, I have the pipe diameters lengths and fittings, but not sure how the radiators and the boiler itself work into the calculations. TACO 0010.

EdTheHeaterMan

8.7 GPM should be no problem with 1" copper. I thought you were going higher than that like 13 GPM.

hot_rod

A 1” valve and all 1” piping would be adequate 

OldawgBryant

Excellent. Thank You!

TommyA

Greetings. First post so take it with a grain of salt . And I'm probably too late for @OldawgBryant , but I am currently (as I type!) going through the same process using the Caleffi 280 and wanted to share some real life experience. Similar situation, old gravity system converted to forced circulation many years ago. Time for a new boiler. Not a heating guru...

Regarding the Caleffi 280, great valve but two things to note/be aware of:

1) There is no way to manually open the mixing valve. Meaning, when the system is cold, water is trapped on the cold side of the valve. Add a drain! Luckily for me I just happened to locate my DirtMag right there and was able to use it to drain the return side. Otherwise I would have had to drain many many gallons through the unions!

2) And maybe more importantly, I too was trying to get by with a single circulator (no primary/secondary). But what I noticed was that until the 280 mixing valve is fully open (which for me happens at 158 degrees) you're only getting a trickle of water out to/from the system. Nothing close to what your circulator is producing. So for the hours+ it takes to heat 100 gallons of water, I'm basically back to a gravity system. Which would be okay if it hadn't been modified over the years to include some wonky branches which got no flow at all (cold radiators).
So your mileage may vary, but this week (after my parts arrive from SupplyHouse.com) I'll be reworking the upper section of my piping to create a secondary loop with it's own circulator so I can force all that water around the conveyor belt! Fortunately I can do it in such a way to leave the near boiler piping alone.

EricPeterson

@TommyA - regarding your two points:

• I piped mine so I could bypass the valve in case it was not working to my satisfaction.
  
• my setup has worked perfectly with a single circulator, and I have three zones spread over four floors with lots of baseboard and free-standing radiators.
  

Eric Peterson

TommyA

Sorry, one other thing I forgot to mention about the 280 valve. After the thermostat is satisfied and the boiler shuts down, as the water cools and the valve closes again (for me at 140 degrees), if there is another call for heat, you can't just circulate with the boiler off to take advantage of the residual heat in all that water (my Weil-McLain controller tries to do this, to no avail). This is because the water is just short circuiting through the 280 valve back to the boiler. A secondary circulator will solve this.

TommyA

@EricPeterson Thanks for your comment. And I guess that's why people call pros . I'm pretty much one and done with this whole boiler stuff!

But, and sorry for my ignorance, doesn't bypassing the valve also bypass it's purpose? That is, to eliminate sustained flue gas condensation? I'm running a non-condensing boiler.