Peerless 63 series "L" boilers

Hap_Hazzard

Peerless makes two versions of their 3, 4 and 5 section 63 series boilers, one with an "L" in the model number and one without. (See the ratings chart, below.) The "L" versions have lower energy input and output than their counterparts and are slightly less efficient.

Looking at the replacement parts for each leads me to guess that the "L" boilers have fewer burners than their counterparts, but I don't see any description of what the differences are in their literature. The "L" boilers are only about $100 less, so you're definitely paying more per BTU and getting a slightly less efficient boiler, so I'm wondering what the upside is, other than potentially getting a boiler that more closely matches your radiant load. Would a boiler tend to last longer with a smaller fire under it? Would it be even less efficient to use an oversized (by about 75 ft.²) boiler?

I'm also wondering if it's possible to upfire an "L" boiler if I decided to add another radiator or two somewhere down the road by ordering the replacement burner assembly and gas control for the non-"L" version.

Does anyone have any experience installing both versions of these boilers?

ethicalpaul

I bought the 63-03L after researching some of that same information. I went with the L due to EDR size match, I don't care about a tiny efficiency difference or $$/BTU vs having an oversized boiler (again).

I think @Dave0176 recently posted about changing out the burner tray (and maybe some exhaust parts as well) to convert one. I'll look for it. Edit: here it is! https://forum.heatinghelp.com/discussion/170347/peerless-repipe

I think it's a pretty straightforward part swap.

Dan_NJ

I've been dealing with a 63-04 and I wish the original installer had the presence of mind to suggest the 63-04L which would have been a better match the existing EDR. He didn't add up the EDR at all AFAIK. The 64-04L would have provided a path for future expansion without a need for a big new install or frankenstein setup of some kind. As it stands now I am about 40% oversized. Not the end of the world but would be have been better off with the L.

Hap_Hazzard

Have you looked into doing the conversion to the "L" burners?

ethicalpaul

You can switch it!

Dan_NJ

As it stands it only really cycles on pressure when the temperature dips below maybe 25F, and then not continuously, so i'll leave it as is. The Cycle Guard probably helps in that regard. It's the near boiler piping that really needs a re-do. Not something I can take on myself.

Hap_Hazzard

Sure you can! If I can do it, anybody can.

STEAM DOCTOR

Weil Mclain has same thing. EG-30 and EG-35 for example are the same block with different burners. The drafthood is different. Relatively easy to swap.

wz25

I'm Dave's customer re: the Peerless repipe and downfire. I can confirm that the only difference between the 63-03 and -03L is the manifold. Dave swapped them out, adjusted the gas input, tested combustion, and we were good to go.

The motivation for downfiring was getting the boiler EDR closer to our radiators' capacity. Can't speak to impact on efficiency based solely on this, but I expect any downside would be more than offset by going from >40% oversized to ~10%.

JUGHNE

Did ChrisJ do the down fire on his boiler like this??

Chris_L

The current Peerless literature tells a different story about efficiency. I just copied this from the Peerless website:

It indicates that the "L" models are slightly more efficient, not less.

JUGHNE

To me that stands to reason: same amount of iron and water for steaming with less fire under it. Also less short cycling if that is an issue.
Just a little more efficient for the "L" on steam, less efficient on water. It is really splitting hairs but those are the numbers.
But why less on water?

Hap_Hazzard

Chris_L said:

The current Peerless literature tells a different story about efficiency. I just copied this from the Peerless website:

It indicates that the "L" models are slightly more efficient, not less.

Actually, what's changed is that they discontinued the standing pilot option. The spark ignition AFUE for steam was always a little higher on the "L" models. I was looking at the standing pilot numbers, because that's what I have now, but it looks like you can't get it anymore.

JStar

The L burner tray does indeed have less burners. One consideration about that is that the flame pattern and impingement under the sections changes. If I remember correctly, the L burners are not directly between sections, so the flame spends a little extra time under metal instead of going right through the boiler passages. Probably insignificant, but something to think about.

Hap_Hazzard

JUGHNE said:

But why less on water?

Yeah, I can't see any reason for that. I'm not even sure I understand why the Ls are more efficient with a spark ignition and less efficient with a standing pilot. ¯\_(ツ)_/¯

Oh well. It's a moot point if you can't get the standing pilot anymore.

Chris_L

Yes, I realized after I posted that the Peerless spark-ignition efficiency numbers haven't changed--but you can't get a standing pilot boiler today from any manufacturer.

Standing pilots were prohibited by efficiency standards that came into effect several years ago. Apparently, the energy consumed by the pilot is greater than the heat loss and electrical energy associated with the spark ignition.

But if I remember right, the efficiency numbers are based on the assumption that people leave their standing pilots on all summer (i.e., in the non-heating season), which I don't do with my two standing pilot, millivolt boilers.

Hap_Hazzard

I always turn mine off in the spring too. I always felt that the pilot wasn't really wasting fuel, because most of the heat goes into the boiler, so there's that much less work for the burners to do when they come on.

ethicalpaul

I know he has a lo/high fire setup. I don't know the details though. @ChrisJ ?

ChrisJ

ethicalpaul said:

I know he has a lo/high fire setup. I don't know the details though. @ChrisJ ?

My boiler is only 1 stage, my A\C is 2 stage.

ethicalpaul

I'm so old

JStar

I tried to convince Chris to go two stage, but apparently THAT was too much, and not the thousand other things he's done to his boiler.

Hap_Hazzard

@JStar, can you say more words about how that two stage conversion works? Do you use the "L" version burners or the non-"L"?

JStar

I use a Robertshaw 700 series two-stage gas valve triggered into low fire with a vaporstat. As the boiler builds pressure, it trips the low fire valve and simmers until the system satisfies. I try to set the vaporstat at whatever pressure is needed for steam to fill the mains. This can be done on any existing atmospheric boiler.

Fair warning: the manufacturers don't endorse this.

Hap_Hazzard

So you're downfiring the larger burner array rather than upfiring the smaller one?

I assume this two-stage valve isn't available with a new Peerless, is it?

JStar

Correct. Low fire is roughly 60% load. Combustion results have always been safe and efficient when I've done this.

Since Peerless doesn't approve of this, they won't build it this way. You can do it on your own if you assume the liabilities.

Hap_Hazzard

Sounds like another reason to prefer the 63-04 over the 63-04L. I probably won't be replacing my boiler for another five or ten years though. Plenty of time to change my mind.

Thanks for the info.

ChrisJ

JStar said:

I tried to convince Chris to go two stage, but apparently THAT was too much, and not the thousand other things he's done to his boiler.

I guess I never saw the point.
Even with 5 TRV's my pressure rarely if ever exceeds 1" WC and I see no reason to put a bigger burner in (go back to EG-45) because it didn't really benefit anything.

I just upgraded the wiring harness because I got tired of WM's rat's nest.

ethicalpaul

JStar said:

Correct. Low fire is roughly 60% load. Combustion results have always been safe and efficient when I've done this.



Since Peerless doesn't approve of this, they won't build it this way. You can do it on your own if you assume the liabilities.

This is very interesting to me. I have an understanding that as you change the gas pressure delivered to an atmospheric burner's manifold, you change the combustion gases.

I also have an understanding that things like two-stage gas valves exist and that some manufacturers don't approve. And they also don't approve of adjusting the firing rate.

They often say "3.5" period. But during boiler maintenance, doesn't the tech adjust the manifold pressure to minimize harmful gas production and to maximize efficient fuel burn?

Is it that those adjustments are very fine compared to down firing or the use of staging?

Is it one of those things that has gotten tightened over time due to increasing knowledge about CO risks, etc, and that in the past it wasn't considered a "big deal" to modify?

JUGHNE

I have had the same question Paul.
However you are not just changing the gas pressure/flow,
IIRC the amount of gas flow also dictates the air flow pulled into the burners. Most likely there is a fine line of adjustment.
Manufactures most likely assume not all boilers get combustion tested and by stating 3.5"WC and the air is fixed then their piece of the liability pie is lessened.

For instance the gas top burner is varied only by the gas flow and supposedly life is good........not going to go there concerning combustion testing!.....that would throw this thread into chaos.

ethicalpaul

Thanks @JUGHNE I appreciate it.

In the past, techs would just adjust the valve until the flames looked pretty and blue, right?? Or did they always have at least a physical manometer (tube type or similar)?

The gas top burner: it actually is scary if you think about it. There's not even a flue!!

JUGHNE

30 years or so ago you just turned it on and walked away.
Maybe adjust the air a little for the blue.

For the most part, gas pressure was assumed to be good.

JStar

Older systems had burners with primary air shutters so you could really get them tuned in right. Now, there's typically no more shutter. They assume a fixed rate of fuel/air mixture plus a hefty amount of (extremely inefficient) excess secondary air.

My philosophy is that you can do whatever kind of work you want as long as you verify its consistent safety while operating.

With the two stage valve, your combustion numbers might show extra secondary air in low fire, but the fuel savings of using 60% load makes up for stack losses.

ChrisJ

JStar said:

Older systems had burners with primary air shutters so you could really get them tuned in right. Now, there's typically no more shutter. They assume a fixed rate of fuel/air mixture plus a hefty amount of (extremely inefficient) excess secondary air.



My philosophy is that you can do whatever kind of work you want as long as you verify its consistent safety while operating.



With the two stage valve, your combustion numbers might show extra secondary air in low fire, but the fuel savings of using 60% load makes up for stack losses.

But the burner will just run 40% longer? No?

JStar

Sounds logical, but no. Low fire is nearly matched to the radiator load (it's adjustable), so once the mains are full of steam and hot, low fire produces enough to cover your emitter load while maintaining a slight back pressure. Commercial boilers do this with more controlled modulation. They ideally run 24/7 in low fire. Startup and shut down are the biggest points of break downs.

Hap_Hazzard

So… no CycleGard then.

JStar

Nah. I haven't touched one in years. This big stuff is all float type LWCOs like 150s, 63s, and 157s. If the LWCO shut a boiler down every hour, the boiler operators would throw them in the dumpster.

Hap_Hazzard

Let alone every 15–20 minutes.

I've come to the conclusion that buying that CycleGard was probably the dumbest thing I've done. It's hard to believe they're still on the market. Why design an LWCO to work with foaming boilers when the cure for foaming is to skim and not add any chemicals that make it foam? Maybe there are some places where good water quality is unattainable, but there are a lot more CycleGards out there than there are such cases.

JStar

I'm assuming, like anything else, it's to accomodate the worst possible conditions. Controls for residential systems need extra safety features to make up for a lack of full time on-site operators.