Buffer tank ,Mod Con, how to?

Ronbo

im no pro but

i would think the hot water heater should stay on priority 1 by itself.

what temps are you running?

mage182

Heating Temps

The heating zones are on an outdoor reset. Min temp 120, max temp 160. Usually it sits around 130-135.



The IHW tank runs at 170.



If everything is piped to be equal, and the larger the load the better, then isn't it a good idea to remove the priority? I haven't had a problem with hot water so far since we only have 1 bathroom right now.

NRT_Rob

you could argue that either way

but I would stick with priority. You have a reset curve because you want one, presumably, so defeating it on a DHW call isn't ultimately that great of an idea.

scott markle_2

Series loop?

Ronbo,



I want to help but it's hard to understand what your saying sometimes.



If you think you can turn all of your zones into a big series loop, then this forum is doing you a big disservice, you may get a fantastic delta, but unless you have a really big pump your flow is going to be pathetic. Even if creating a giant loop didn't wreak havoc with distribution (it will), it's not going to transfer any more energy piped that way.



Is the wall is getting soft?



Trust me integrated zoning reset controls are the way to go, the problem is as much about control as sizing. You seem adventurous.. put in a 400 house control and the 527 stats you need to go with it. All the documentation a technically literate person needs will come along with hardware... If you get stuck, well it's not that cold down in jersey... and I'm sure you will be able to find a sympathetic contractor willing to sort things out without charging you service rates.



BTW- Are you saying that even after putting all your zones on one thermostat and turning your maximum modulation to 20% your still short cycling?





Online vendor for Tekmar- http://www.pexsupply.com/Tekmar-400-tN2-House-Control

furnacefigher15

Ronbo

Does the boiler still short cycle?



"1st off- 4 pipes at 4 gpm=16gpm vs 1 pipe = 4gpm seems odd to me but I guess if 4 gpm is 20 degrees cooler vs 16gpm 5 degrees cooler

So the savings(btuh) i reap (condisatinting )goes directly toward current water heating yes? wont it just be applied to my already low of 20%? meaning to take advantage i would have to run hotter temp?"



To answer this question, No don't just run them all in one loop, but I would try to match the gpm capacity of the pipe to the amount of heat emitter on that pipe.



Meaning each size pipe has a peak gpm capacity before velocity noise becomes an issue.



I'll give the common pipe sizes found in a home.

1/2 inch is good to 1.5 gpm

3/4 inch is good to 4 gpm

1 inch is good to 8 gpm

1 1/4 is good to 14 gpm for copper and 17 gpm in steel

1 1/2 is good to 22 gpm for copper and 25 gpm in steel



To find the btu limit of the pipe, multiply gpm by 10,000 (20 degree delta drop)

So on a 3/4 inch zone loop, 40,000 btu / 600 btu per foot (180 ) = 67 ft baseboard



"zone1 has 43' of baseboard and 100' coppper supply/return zig zagging about the ceiling in basement to feed it. about 18 elbows heat loss is 15,285 in this area i could add/use 2000 more btuh for this area

zone 2 = also in basement can be joined to zone 1 if needed and is 12' of base with 26' of s/r pipe copper pipe 7 elbows. heat loss calculation is 7000 in this area.

zone 3=has 68' of baseboard, 93' of s/r copper and a toe kick 5150 btu.and could use another 2000 btuh to help out. heat loss is 25,038 in this area.

zone 4 = 46' baseboard 130' s/r pex 3/4"



So like I was saying in an earlier post, Zone 2 is too small of a zone for your boiler, and should be run in series with zone 1 or zone 4, or have about 50 feet of baseboard added to it, or be eliminated all together. Zone 3 is at it's limit, and should be left alone.

Ronbo

better

Ty all, i am leaving them run in parallel and adding the small zone2 to zone 1. But can I throttle back 1 afterwards to reduced the BTU into that zone to even things out? That zone gets warmer than most. I know that will change the return temps a bit but I'm getting to good numbers now and ill be adding some BTU to zone 4 soon. Im hoping to add some radiant floor heat from under the floor in zone four at the end of the loop so ill get a better delta there and some much needed heat to that bath floor

furnacefigher15

Sounds like a plan

I like the idea of adding a infloor loop to the end of a existing zone loop. This is called load stacking, and is a great approach to create lower return temps.



You can throttle the btu output, by tinkering with the flow in that line, or if you put the the zone 4 in series with zone 1, but have zone 4 get the flow 1st and zone 1 get the flow from the output of zone 4, you will lower the water temp to the zone 1 loop by a few degrees, and that alone may be all you need.

Paul48

reading

for someone else