Lochinvar/Caleffi Mechanical Schematic: Whats wrong with it? Pics attached

Zyzzor

Hi guys, thanks for all the great knowledge found on the forum. After a lot of back and forth with the pro's in my area, I've decided to go with a lochinvar boiler/indirect HW setup. My pex lines are all installed on 3 floors and terminate in the basement. I've been reading the caleffi idronics series, and talked to a tech rep last week, and I think I have a system figured out........ My questions. 1. I've put a caleffi hydrolic separator in the indirectWH/ main loop.... is that a bad idea? as I have hydrolic separators in the caleffi mixing stations and there's a pump on the loop? 2. What pump should I use for the indirect/main loop? thanks for any ideas! Pics attached

STEVEusaPA

I’d put the indirect on the boiler side of the separator.
The PEX looks like a mess, to out it nicely

Zyzzor

Oh, yeah, the pex is a mess currently. I left it all long and put pressure testing manifolds on everything while pouring concrete on 2 levels. That will get get sorted for sure.

Zman

First, please clean up the spaghetti. Shorten the upper loops and move the manifolds up, hard pipe to the near boiler piping.

The way you have this drawn, the indirect will not work. The water will just shortcut through the separator and very little will go to the indirect. Water is lazy and will take the path of least resistance.

What are the design temps of your radiant loops? Why the mixing? If the radiant temps are close to each other you can do domestic priority and outdoor reset control for heating. The system will be more efficient and house more comfortable.

Zman

This is what Lochinvar recommends:

unclejohn

I would think that if the WH is on a priority and the other pumps off it would work. Or you can add a pump for the WH and that should also work.

Zyzzor

Thanks for the lochinvar drawing! very helpfull. Yeah, I see what you guys are saying about the 4in1 separator.. I'd be better off with a separate air/ and dirt/mag, letting the separators on the manifolds do that work....Yes DHW will have priority...The reason for the mixing is that my tubing is in concrete slab= Low temp, between between 90-105, I think....I'll be zoning with circuit actuators on the top manifold (3 zones). The bottom manifold will be one whole zone although I originally had it as 3 zones, but after reading a lot of comments about micro zoning a boiler cycling I decided to gang them all together. I'll redo my drawing and repost later today, and see what you guys think

Zyzzor

Fyi, this is new construction, and when I started this project 3 years ago, I was gonna do a tankless for two floors and a combi for radiant and the lower bathrooms....I'm glad I didnt go that route...I know some folks scoff at the DIY'ers but when I got estimates for the system during planning, the two that I got came within 5 bucks of each other at 60K....No way I could afford that so I had no choice.... Thats the story of this whole house... my girlfriend, her dad, and I have done almost everything. Attached are a few photos from over the last 3 years during the process. I need a day off!

HomerJSmith

How would you move water thru the Lochinvar HX in your original drawing? What about flo checks? hmm.

hot_rod

In your drawing you need to add a circulator on the indirect. Connect it to the boiler DHW priority so it kicks up to high temperature.

Those Caleffi pump stations do have a LLH built in, so you need to eliminate that also if you use a hydraulic separator.

Stick with the Sep 4, it solves a lot of issues.

Zman

I would be willing to bet that all the assemblys in you pictures could run at the same temp. A room by room heat loss would be needed to confirm.
If they can run at the same temp, you could lose the mixing valves and really simplify things.

Zyzzor

Thanks @hot_rod ! If I wanted to utilize the Separators on the manifolds, I could then put an air sep on supply and dirtmag on return and it would provide the same service, correct? here is that drawing with the added priority pump.

Zyzzor

@Zman I have concrete slabs on two floors so because of the thermal mass, I'm hoping to mix them down to between 90-105 degrees. I'd like to maintain the indirect around 125-130. Thanks for all the input.

hot_rod

Why not run the boiler 95- 100 at design, set the outdoor reset around those numbers.
The boiler will kick up for DHW on it's own, wire the indirect to DHW contacts in the boiler. No need to run it at high temperature and mix down.
Depending on the Lochinvar minimun flow rate, you may be able to direct pipe. If you are individually zoning at the manifold, you may not meed boiler minimum flow requirement, so a hydrosep would still be a good option.

I like the sep option so you get all 4 functions in a neat clean piping. I also like the indirect before the sep for quick DHW, no need to heat the sep and piping for indirect call.

Zyzzor

@HomerJSmith Yeah, I added a pump to the new drawing above. The caleffi manifolds have check valves in the Separators from what I can tell. I probably need a few more. Where do you suggest I put them? Thanks!

Zyzzor

@hot_rod Aaah OK! I get it now. Yes.... Thank you so much for the sketch. I understand what you're saying. I do like the sep4 concept. I'll redo my drawing and repost I ordered my manifolds today from my local ferg rep....I'm guessing you are the same hot rod on all the Caleffi videos..... Those are great! I've learned sooo much! Appreciate your commitment to folks like like me.... thats pretty cool!

hot_rod

Zyzzor said:

@hot_rod Aaah OK! I get it now. Yes.... Thank you so much for the sketch. I understand what you're saying. I do like the sep4 concept. I'll redo my drawing and repost I ordered my manifolds today from my local ferg rep....I'm guessing you are the same hot rod on all the Caleffi videos..... Those are great! I've learned sooo much! Appreciate your commitment to folks like like me.... thats pretty cool!

Thanks, glad to add my 2 cents.

Zyzzor

@hot_rod here's my updated drawing per your advice. How's this look? I'm thinking that I order the 1" Sep4 and put in 3/4"x 1" x3/4" tees for the manifold branches with check valves. Thank you for the heads up on outside reset. Its a concept Im still wrapping my noggin around. I'd love to see an idronics on that!

Zman

You don't need the mixing stations at all. If they are thermostatic, they will mess up the outdoor reset.
Control the DHW with priority and use the boiler's outdoor reset to control the heating water temp. No mixing valves required.

psb75

I think you should look at Hot Rods simpler drawing and study the concept of outdoor reset and you will save some money on the build and the operation of your system.

hot_rod

I agree, abandon the mix valves, here are some examples.
1: the boiler will be most efficient under two conditions, the lowest return temperature and lowest firing rate. Keeping below 130 will increase the efficiency a bit.
2: Running at low fire also as you expose a lot of boiler HX surface to a small flame.

Idronics 25 goes into good detail on both low operating temperatures as it relates to mod con efficiency, and also the details about outdoor reset.

Possibly you can run. the 105 and 90° zones at one temperature? Maybe 100°. need to get to design condition to know that.
One rule of thumb id if zone temperature requirements are within 10° of one another, no need to do additional mixing. You are a bit beyond that, but you load calc and design may have enough fudge that both would be fine with 100° SWT.

AND, if that is true, that boiler will be very efficient running 100° and lower for heating loads

You want to install the "System Sensor" from the boiler about 12" or more downstream from the hydro sep supply to the system. It will see an accurate "blend" temperature there.
Dial in the ODR and that system may run 80- 100° SWT it's entire life, that would be great!

Zyzzor

thanks @Zman @hot_rod and @psb75 I need to do more homework on outdoor reset. Thank you so much for all the feedback!