Boiler Install with questions

Frank_63

Background: I live in a 100 plus year old extensively remodeled farmhouse. I bought it in 1979 and according to my wife have been working on it ever since. The previous owners did eye dressing remodeling in 1972-1973. The original boiler was an American Standard 210,000 BTU seven-burner cast iron on propane. It had 3 series loops, upstairs, downstairs, and utility all 3/4 copper with finned baseboard with one B&G circ pump with no zone control, one t-stat. has the baseboard. The only control was with balancing valves. Very little insulation, cheap windows, drafty etc. It ran 180-degree water and it didn’t take long for it to cut out on the high limit. Over the years I did extensive insulating, new windows, building wrap, siding, installed a freestanding wood stove etc. That really emphasized the over sizing issue. I got pretty good at balancing the system when it was running, I guess I was the ODR and zone control. I removed the old boiler a few years ago as I added an addition and redid the dining, kitchen and utility. I’ve been using my wood stove and electric heaters, which gives me flexibility as I do work. I had some military duty during this time, which slowed things a bit. My wife says its time to get some real uniform heat in the house.
I am installing a Munchkin 80M boiler with P/S piping with a Taco 007 on the boiler loop. After reading more info on the “Wall”, I do have concerns now about this unit, but it’s what I have. I have 3 zones with separate t-stats, and 3 separate Grundfos 3 spd circs, and an Amtrol indirect DHW with a Taco 007 circ. I do have 2 stubs in the manifold for future loops. The only new finned baseboard is about 24’ of ¾” Suntemp Imperial 700A on a loop in the addition with return pipe in the unit. The downstairs loop is 62’ of ¾”, in dining, living and bedroom. The upstairs loop is 72’ of ¾” in two bedrooms. I know I am sacrificing some control and uniformity in each room on these series loops. I will remove fins if needed and use the dampers, or what other strategy can I look at. Bathrooms have small electric wall heaters, but I may look at toe kick type units.

I have done heat loss calcs using the Slant Fin software and also the stubby pencil method, both were pretty close. Since I’ve done all the insulating, remodeling etc. myself I know the theoretical values.

Since the low end of this boiler is 27000 BTUs, is it likely I will see short cycling if only the 24’ loop is calling for heat, or even one of the other loops? Knowing my house that is possible if and when I use the wood stove. Would a buffering tank to add volume be a good idea to get longer more efficient run times, which could prolong the boiler service life, and take advantage of the Mod/Con design?

What is kind of a benchmark minimum footage for ¾” finned baseboard on a separate loop? With the existing baseboard and layout there is a lot of ¾” regular copper piping to make the loops. All of this is within the house envelope so it does contribute. The original ceilings were 9.5’ and in the 1972 remodel were lowered to 8’. A lot of the feed and return piping is between the original and the current ceilings.

Boiler has the 925 controller. What is my best option(s) for an add on controller(s), to give DHW priority, individual control of each zone circ with t-stat which also starts the burner and boiler circ on any of the zone calls for heat or DHW. I would also like ODR. I was looking at zone controller/switching relays, either the Grundfos UPZC-4/6, or the Taco SR506. Can I run a higher temp for the DHW if it has priority over a lower temp heating zone, or what is a practical minimum temp to use and still maintain DHW? I know lots of factors to consider. The indirect DHW will replace an Aqua Star tankless propane water heater, 44K-125K BTU. I installed in 1987. I descaled the unit once and put in a rebuild kit. I had run it 3 years before I installed the water softener. Starting to get some leaks on some fittings, but the burner and tubing exchanger looks good. It has been a good reliable unit. An infantry company could take showers as long as there was water and propane available. Not opposed to multiple controls to meet these goals if possible, but trying to keep compatibility, functionality and ease of use and install reasonable for this particular boiler.

I have a 12x15 utility room with 4” concrete over 5” crushed compacted stone that has 60 feet of ¾” copper embedded in the stone. Probably not a good idea to be buried in the stone, but it probably sounded better 15 years ago when it was done. No real design on this or projected longevity. The concrete and stone has 1” perimeter and 2” under, extruded foam. I would like to run low temp water through this, or possibly in the future set it up for a solar application. What type of heat transfer could I hope to get from this, without suffering thermal stresses? No finished floor on the concrete yet, but probably will be a quarry tile. Would installing radiant tubing directly on the concrete and doing a thin over pour of some type of concrete product be a better option? I can probably deal with the increased floor height.

Just some questions:

What is BTU output of ¾” finned copper baseboard versus the ¾” thin wall copper with fins removed or type M or L? With the return line in the finned baseboard unit what would be an estimated BTU increase? Is there an easy calc or estimate to figure this across the different input temps and flows. With the damper closed and convection reduced do these units act more like radiant and what would be a rule of thumb to estimate output? Since a lot of the outside wall perimeter is baseboard how does furniture placement and draperies affect the heat output, convection and or radiant?

I live in a rural area with well water, some sulfur, iron, calcium etc. Everything is run through a whole house filter and Kinetico softener. I use salt or potassium chloride in the brine tank. I know there is residual left after back flushing, that is why I use the potassium if possible. Can these residuals cause any issues with a Mod/Con as long as no continuous make up water is added?


I know this sounds like a novel. I’ve learned a lot from this site, even about steam, which I will probably never deal with. Any thoughts, opinions, product likes/dislikes, ideas greatly appreciated.

Frank_63

clammy

munchkin

mike instead of using all zone pumps use some zone valves and install a differntal by pass valve and use just one system pump ,pipe the unit according to htp and use the vision one kit ,you can run your system pump with the boiler pump off of the boilers central heating pump,defently use the outdoor reset included with the vison one .You can check with your slant fin program the output of the baseboard at lower water temp.I have install munchkins using standard and light commerical baseboard with very good results ,how about towel racks with trv for those bathrooms much better then toe space heaters and usefull .good luck clammy