DIY Boiler Install - Opinions?

JaToTheD

Hello,
Aside from 'Have a professional do it', any advice on the setup below? Are there folks here willing to look at the system setup in the image below? That is a Lochinvar WHN-110 ModCon boiler, with P/S piping, 2 zones with circs, and a Taco 3-zone relay. The 3rd incomplete zone is for future use (garage, once it's insulated). I am currently in IT, but have a background in Hospital Facilities services - prior licensed boiler operator, so I do have some plumbing experience. I have spent several months reading the I&O and other materials for all of the equipment here. I'm hoping that if I've made any glaring omissions or mistakes that someone can point them out. (By the way, I'm not sure if anyone else uses Sketchup for this sort of design work, but it works really well!)

Thanks in advance!

delta T

I too use sketchup, usually not to this effect though, where did you get all the models for the components?

To answer you questions, I see nothing wrong with the way it is being piped, I would however consider using zone valves and one ECM system circulator before using individual zone circulators. While there is nothing acutually 'wrong' with the way you are doing it, you will likely lose efficiency by overpumping the zones. What kind of radiation are you using (baseboard, radiant floor, panel radiators, etc...)? Has a heat loss been done in order to determine the sizing of the boiler? A 110,000 btu boiler sounds awfully large for a house small enough to only need two zones. If you sized based on the garage addition too, it may make sense, but only if the garage is large and poorly insulated. Once you determine the amount of heat needed for each zone and take into consideration the radiation you are using, you can determine the flow rates necessary for each zone. I bet you will find it hard to get a pump that will be small enough to achieve the required flow. You would be surprised how little you usually need.

Please make sure you are right about the heat loss, as over sizing a boiler, especially a ModCon, will cause lots of headaches down the road, and you will not be pleased with its performance.

delta T

Oh also, as detailed as your drawing is, I don't see a condensate neutralizer, make sure you install one. Also, you don't need the air scoop air eliminator above the expansion tank, just the micro bubble resorber you have shown at the top of the supply before your manifolds.

JaToTheD

Thanks Delta T! It is a small house (1200 square feet), poorly insulated, old doors and windows(working on those issues too). I did do my own heat loss calculation of the house, and with just the house, The boiler is oversized, but with the unattached garage, (it will be converted to a woodworking shop) I think I'll be right in the ballpark. This boiler has 89k btu output, and my heat-loss calculation came in right around 58k (before the garage). I'm using baseboards in most areas, but have 2 kickspace heaters for the Kitchen (3370-10360 btu output each). I live in Montana in an area where it got down to -30f a few times this past winter.
I found most of the items for sketchup in their '3D Warehouse' - lots of the fittings were PVC or other materials, but I resized them to scale, and changed the color. I also custom-built a lot of the items (like the Taco 4900 air separator, air scoop, and boiler fill valve). I'm happy to share all of those components on here if you'd like, or I can post them to the 3d warehouse in Sketchup.

Ironman

58k btus? That's 48btus per sq. ft. which seems high even for the design condition that you're describing. I'd recommend re-doing your heat loss calc with the construction data for what the house will be AFTER you've tightened it up. Then do the same for the garage. Then size the boiler for that. You'll probably get by with the 085 model.

And, look at using the KHN model which has a 10 to 1 turndown to minimize short cycling.

Steamhead

Spend your money on tightening your thermal envelope first. Then buy a smaller boiler.

Zman

I like the design. I also agree with the comments above. They make an 80 or 85 model which would be more than enough.
Look for the Lochinvar firetube with 10-1 coming soon

Ironman

Zman said:

I like the design. I also agree with the comments above. They make an 80 or 85 model which would be more than enough.
Look for the Lochinvar firetube with 10-1 coming soon

Zman, it's here: it's the KHN model.

Zman

Thanks for pointing that out Bob. I get confused with all the acronyms...

hot_rod

Consider the Lochinvar Nobel model also if you like that brand. They have several combis with 10- 1 turndown, a 120,000 I believe is the smallest size.

It has a rather unique DHW function fire tube boiler with plate HX and the option to keep the boiler "hot" for near instant DHW.

I'm going to try one in my home this season.

Being a fire tube you may not need primary secondary or hydrosep, depends on emitters, etc.

Ironman

Zman said:

Thanks for pointing that out Bob. I get confused with all the acronyms...

Z, I get confused with a lot of stuff. I just left a customer's house and three minutes later couldn't remember their last name when asked.

I think I've got half-timers.

NY_Rob

You need to supply details regarding your emitters...

Fin tube, cast iron, radiant, etc?

If fin tube... the length of actual fin tube (not the overall loop length) in each of the zones?


The WHN-110 has a minimum output of 22K BTU's... in a 1,200 sq/ft home your radiation per zone may be insufficient to support that high output at condensing temps (below 130F).
There are mod-cons with lower total output and 10:1 turndown ratios that may suit your needs- but more info about your emitters in needed.

JaToTheD

Thanks for everyone's responses - all very helpful. I will definitely redo my heat loss calc, and consider a smaller boiler (perhaps the KHN version). I was wondering if the condensate neutralizer was required or not, and it sounds like it is, so I'll add that. The emitters in zone one are fin tube (slant/fin fine line/30), and are 36' total. Zone 2 is 32' of fin tube, and the two kick-space heaters (Beacon/Morris K84s - 3370-10360 Btu output each). Zone 3 (planned for next year) will probably be about a 30k btu hydronic unit heater for the wood shop/garage.

Ironman

Realistic output of standard 7" baseboard is about 500 btus per lineal foot of element @ 170* AVERAGE water temp (180* supply, 160* return).

This means that either of your zones would be well below the minimum firing rate of the WHN and you would have short cycling which would greatly reduce the life of the boiler and decrease its efficiency.

Again, look at the KBN 085 or HTP's UFT 085. Both are 10 to 1 turndown.

NY_Rob

The 36' fin tube zone is going to make that 22K BTU minimum output boiler short cycle.

The very beginning of the MOD-CON condensing zone (which is only in the 86-88% efficiency range) starts with 130F Return Water Temperature. Even 120F RWT only gets you 90% MOD-CON efficiency.

With that in mind and using a standard 20F degree change in temp between SWT (Supply Water Temperature) and RWT...
Start off with a 130F SWT and a RWT of 110F which gives you an Average Water Temp of 120F and 90% efficiency from your MOD-CON.
-120F AWT gives you 210BTU/ft from fine line 30 baseboard.
-Your 36' of baseboard at 120F AWT will only radiate 7,560 BTU's.
-The boiler can't supply less than 22K BTU's.

Something's got to give... so the boiler short cycles.

NY_Rob

Here's a pretty standard Condensing Chart to illustrate the effects of return water temps on MOD-CON efficiency...

NY_Rob

Here's the Fine Line 30 output chart....

DC123

Bob, out of curiosity, do you see an advantage for the Lochinvar Noble over the NTI Vmax? Both are 10:1. I guess that the Noble has one of the lowest minimum outputs for a combi, but with that model, your DHW production is only 2.6gpm at a 77F rise. Seems that having the small indirect in the Vmax may offer more flexibility...

bob eck

You could use the Lochinvar Noble 150,000 BTU input combi boiler that delivers 3.6 GPM domestic hot water and you can down fire the heating side of this boiler to match the heating BTU load of the house. This way you get a higher GPM on the domestic hot water side plus you can adjust boiler heating side to match the house BTU needs. 10-1 turn down. SS Firetube heat exchanger. You do not want to have to many secondary pumps vs the primary pump you could over pump the secondary side of your heating system. You could use one secondary ECM pump with two or three zone valves. Watch your water quality you might want to flush out the old system and then install a Dirtmag from Caleffi to catch any iron in your system. You do not want that in your system it can clog up the heat exchanger and the build up in the heat exchanger can cause hot spots and to much heat in certain spots in the heat exchanger can cause flow problems and cause the heat exchanger to get to hot and to leak and fail prematurely plus that iron can get in the plate heat exchanger and cause that to fail plus the iron that gets caught up in you heat exchanger acts as a insulation causing you to use more fuel to heat your system water and that iron can also kill you ECM circulator pump.

Wellness

I second delta T's comments. Besides his concerns about over pumping, zone valves are more energy efficient than having individual pumps on each zone.

Mark Eatherton

JaToTheD said:

Hello,
Aside from 'Have a professional do it', any advice on the setup below? Are there folks here willing to look at the system setup in the image below? That is a Lochinvar WHN-110 ModCon boiler, with P/S piping, 2 zones with circs, and a Taco 3-zone relay. The 3rd incomplete zone is for future use (garage, once it's insulated). I am currently in IT, but have a background in Hospital Facilities services - prior licensed boiler operator, so I do have some plumbing experience. I have spent several months reading the I&O and other materials for all of the equipment here. I'm hoping that if I've made any glaring omissions or mistakes that someone can point them out. (By the way, I'm not sure if anyone else uses Sketchup for this sort of design work, but it works really well!)

Thanks in advance!

Why two air eliminators? Also, make certain there are check valves installed in the two circulators. Also make sure that the manifold piping increase and decreases according to the connected flow rates, on both the supply and return.

How are you going to purge your boiler loop? (not sure if thats a purge cock down low or not.)

Also, the boiler pump should be pumping away from the PONMIPC, otherwise you may hear whales in heat when the boiler gets hot from micro bubble steam flash at the heat exchanger interface to the fluid.

Lastly, whatever your closest heat loss calculation proves to be, the real time load will probably be half that amount. Unless you are also doing DHW (which it appears you may be eventually doing) do not oversize the boiler.

I live with a reverse indirect for DHW and only have a 32K net output boiler. Only one person or one machine can use hot water at any point in time, but it works great.

Also, condensate neutralizers are mandatory under all codes. You are not allowed to discharge anything into a sanitary sewer that would be detrimental to the piping system without first treating it. It's just not being properly enforced by the AHJ's out there, yet...

ME

hot_rod

Another option would be a multi-function device called a hydroseparator.
This would clean up the piping and provide dirt, air, magnetic and hydraulic separation. Expansion tank connected as shown assures all is well with the PONPC.

nubbyboilerdesign

Delta T
I need help setting up a new system
Can you please help laying the piping for a 3 zone system

nubbyboilerdesign

Can you please contact me at airductsllc@gmail.com.
I am willing to pay you pleaae help me or anyone who is reading this

HVACNUT

@nubbyboilerdesign
This is an old thread. It might help if start your own. Click on the pencil and start typing.
The more details the better.