First time doing heat load calc: Whoa, is my boiler 2x oversized?

jesmed1

Trust the calcs based on actual fuel usage. That's the most accurate heat loss calculation there is. And remember that some of that oil went to heating water in your indirect tank, not heating your building. So your actual heat loss will be somewhat less.

Based on comparing your fuel usage and ours, I estimated you at 45,000 BTU/hr, but that was neglecting the fact that some of your oil went to heating DHW. So your actual heat loss could be less.

EdTheHeaterMan

I agree with you. How many square feet is your home? How many stories? How old is the home? and what infiltration number did you use?

Also are you using that boiler for DHW in any way? Like an indirect?

seized123

@EdTheHeaterMan is it me you’re agreeing with, about the WGO-2?

If you're asking me and not Jesmed, our house is a 2-story 30 yo modular cape, 1700 sq ft finished, with an unfinished, uninsulated but heated garage and basement (if you count them it's more like 2500 sq ft), cinder block walls, half below grade. The garage is very leaky and I think a lot of energy goes into it even with its thermostat all the way down. Four zones, both garage and basement have a zone. The basement, where the boiler is, has an exposed joist ceiling no insulation between it and upstairs. The garage, oddly enough has a finished ceiling and I feel like there must be insulation in there. Indirect DHW heater.

For infltration I went with "standard house, some insulation" rather than "tight construction, heavy insulation," since I don't think my house is tight compared with today's standards for new construction (but you pointed out that the form is kind of old, so my house might indeed be tight by their standards). My selection gives a factor of .018, and with an estimated 20,000 cubic feet of house, and a temp difference of 56F, (65 - 9), I got just under 21,000 btu/hr for the infiltration.

It was confusing how to deal with the garage and basement given that they are heated but unfinished and I wasn't sure how to treat the floor which is just concrete.

pecmsg

getting a Blower Door test done will tell you how much leakage, where the leaks are and where improvements can be made.

EdTheHeaterMan

I was agreeing, until I saw you have the indirect. Indirect DHW = WGO3. In your case you are sizing for your DHW demand. That happens sometime, where you must size for the DHW demand while the space heating is much smaller. In your case, it is not that far off. I have put 3 section boilers in 2 bedroom ranch with only 1200 sq ft of living space, that had a heat loss of 22,000 BTU. The hot water demand required the larger firing rate .

seized123

Okay, WGO-3. That way I wouldn't even have to move the flue ducts due to the smaller size. And I assume then I can use the same nozzle size, .85 x 70b.

EdTheHeaterMan

Correct, you can swap the burner and turn it on. The settings will be fine for a day or two, until you can the combustion test completed.

I would check the wiring on the burner. I believe the boiler less burner does not come with the aquastat relay. You may need to bring that ofer from the old boiler also. You have the new Carlin 70200s and you will want to know if the wire from the Aquastat relay has two or three conductors with a ground. RED WHITE BLACK & GREEN or just 2 conductors WHITE BLACK & GREEN. You will want to get a 3 wire + ground to set up the Carlin 70200s properly.

seized123

Good info @EdTheHeaterMan . The aquastat does come with it, here's the model:

https://www.supplyhouse.com/Weil-Mclain-381-300-000-Electronic-Aquastat-w-LWCO-High-Limit-or-High-Low-Limit-Combo

The Weil-McLain 3-section they have is the WGO-3R:

https://www.supplyhouse.com/Weil-McLain-386-701-013-WGO-3R-85000-BTU-Output-Cast-Iron-Gold-Oil-Boiler-Series-4

about which the brochure says:

R = Reduced input version—a burner nozzle change maybe required, refer to the burner instructions or boiler's rating label for correct selection. No separate/additional damper kit required.

Also, the photo shows the included circulator on the supply side, which I've heard is supposed to be better for reasons I don't yet understand. Right now the old circulator is on the return side with the expansion tank. If I raised the new boiler to the same height, there would not be room below the zone valve manifold to put it. If it's that important to have the circulator on the supply side, I could put the boiler on only one or two blocks instead of four to create more clearance above, although I'd rather not because then I'd have to relocate my tigerloop, which is bolted to a cinder block under where the return pipe enters the boiler, and which needs clearance below it because it has the integrated filter. But if it makes that much difference I'll do it, it's not that big of a deal.

EdTheHeaterMan

Need Pictures of the existing boiler set up.

Perhaps about 10 to 12 feet further back that this photo, so I can see the pipes that connect the boiler to the rest of the system.

seized123

SuperTech

I would completely re-pipe it. You would really benefit from installation of a micro bubble resorber air eliminator, install a Caleffi fill valve and backflow preventer with the pressure gauge at the air eliminator on the supply and move the circulator so it's pumping away from the expansion tank. I would recommend installing a new digital aquastat, L7224U or Hydrostat 3250. Install the Carlin 70200 primary control and use all three wires to the burner so it's constantly powered up. Set the burner for 15 second pre purge and 30 seconds post purge if you have a solenoid valve on the oil pump. I'd install a clean cut pump if you don't.

This would bring your new boiler into the 21st century. It still won't be as nice as a new EK-1 F. That WGO-3 installation you have functions but it could use an awful lot of improvement in my opinion. That's just how I would do it.

SuperTech

That black iron pipe on the pressure relief valve is against code. That pipe should be non-ferrous to prevent rust from building up in it and preventing the relief valve from functioning. I'd use 3/4" type M copper

SuperTech

I'd also be cautious about putting the old burner on the new boiler and running it. The new Peerless WBV-03 boilers now have baffled in between the sections to improve the efficiency a little, but this changed the combustion and draft. I'm not sure if new Weil McLain boilers have the same thing going on or not. Check the manual just to be safe. You can always remove the baffles if this is the case

EdTheHeaterMan

I can see 2 options here.

1. Just keep the circulator in the same place and do the boiler as the original.
2. Raise the zone valves in one large sweep. cut 5 pipes above the ZV and get 5 couplings or valves to put them back together. That will leave the circulator pump on the supply as designed . But you will want to connect the expansion tank at the air vent opening to gain the best advantage of the new circulator location.
   

Based on your skill level with soldering copper piping, You will need to decide what you are comfortable with.

Both options are correct.

seized123

@SuperTech thanks, those are a lot of objects I'm going to have to look up to see what the heck they are.

But does this Aquastat look okay, it's what comes with the WGO from SupplyHouse (or from anyone, I think):

https://www.supplyhouse.com/Weil-Mclain-381-300-000-Electronic-Aquastat-w-LWCO-High-Limit-or-High-Low-Limit-Combo

And is it that important to pump away? If so, I'll do it. And if I do, can the expansion tank stay on the return side where it is, with the circulator on the supply side? (There's not much space to put both a circulator and an exp. tank between the boiler and the zone manifold, and there's no way I can move the manifold.) To put the circulator on the supply side I'd have to put the boiler lower, on fewer blocks, which I'd rather not do, but if it's that much of an improvement…

As for the burner, get ready for another rabbit hole: I've been planning on getting the 'WGO-3R' that SupplyHouse has, they say it could be delivered early next week (or so…). 'R' stands for Reduced Input. Beckett's spreadsheet on their website says that for the 'GO-3R' use an L1 head and a 0.65 x 60B nozzle, and they mention the BR100 chassis. The spreadsheet also says that for the WGO-3 (not 3R) it can be the same as what I have, F3 head and 0.85 x 70B nozzle. I gather it would not be a big deal to change the head on my old AFG to an L, I think I need a different air tube. BUT… I called Beckett's tech services just to check, and the guy said no big deal, the 3 and 3R are both basically WGO-3's, I can throw on the old AFG and use that nozzle size. (That would be nice.) So I'm wondering, is the situation that the physical 3R boiler is identical to the 3, it's just that IF you throw on the L1 head and that smaller nozzle it becomes the 'reduced output' 3R? (The 3R does not come with any particular burner ) And maybe some sellers decide to sell it as the 3R because, well reduced input is good. So if I buy a 'WGO-3R' from SupplyHouse but put my old burner on it, do I have a WGO-3? The guy at Beckett definitely said it's not a problem to slap the old burner and nozzle on the '3R.' (I hope you appreciate just how confusing this is to yours truly.) Now, SupplyHouse only has the '3R', but I see that a WGO-3 is available and possibly (possibly) shippable soon on ecomfort.com, whatever that is, but I'm comfortable with SupplyHouse. And if I got that '3' from ecomfort or whomever just so I don't have to change heads or worry about nozzle size, but it turned out it didn't matter …. Opinions? Do you think all that is the case? In any case I can just trust what the Beckett guy said ….

Moving on, if you mean the horizontal 6" nipple between the pressure relief valve and the discharge pipe, it's brass, the lighting probably makes it look dark.

BTW, speaking of overthinking, I had some time to kill and looked more into Energy Kinetics, mostly on this forum. I want one! (Someday.) I'm starting to believe people about the 30% savings and longevity, clearly lots of techs are saying they love them, but what I mostly believe is that the customer service sounds phenomenal, and that's huge. Things go wrong with everything, but if the company's there for the customers ….

Having said that, given that we may not be in this house in ten years, and maybe not in five and maybe not in three or four, I consider that with an EK, even if I saved $1000 a year, when you consider the difference between the probable cost to have an EK installed on the one hand, and this WM on the other, especially if there's no labor charge because I manage to install it myself (which is now much more intimidating now that I have to consider putting in a micro bubble resorber air eliminator - c'mon, did you just make that up? - and a backache preventer and a Caleffi reverse cake icing nozzle 😉 no, really I appreciate all the suggestions, each one is a learning experience for me), that's a lot of years to make up the difference,, and if I end up losing money what's the point of all that efficiency? If this were our forever house, that would be different. But an EK and the new roof and driveway we need … you get the idea, that would be a lot of Mallomars.

seized123

And thanks @EdTheHeaterMan , picture's worth a thousand words (kWord).

Roger

Thank you for doing your research and considering an Energy Kinetics boiler, @seized123 - we're known for super quiet operation, tons of hot water, and of course longevity and energy savings. The combination of low mass and thermal purge virtually eliminate oversizing efficiency losses, so you have all of the upsides of the full firing rate (fast hot water recovery and pickup for heating), without the downsides of concerns about undersizing.

If we can help out, please reach out to our customer service team at (908) 735-2066 or to Jay McCay, our national sales manager at (908) 328-7154, or PM me.

Since you're researching heating overall, here is a good hydronic reference used in the NORA gold certification training.

Here's another run down on calculating your heat loss using heating degree days; I think it validates your general calculations. You can also remember that you have hot water usage in your annual consumption, so the hourly heat loss will be high from that impact as well. If you are interested, look at summer fuel deliveries to find out how much fuel you use for hot water (make sure the tank was filled each time for an accurate number).

Best,

Roger

seized123

@Roger thanks for the documents, very helpful.

I probably won't get an EK boiler for this house, but at this point that is solely due to the probability of our moving in the next few years; we'd never recoup the investment. I would love to bequeath one prematurely to the next owners, but I'd rather save the money for an EK in the next house.