any suggestions for Munchkin heating curve

Uni R_2

As far as just setting the ODR curve is concerned, it'll end up being an exercise in T&E. Whatever you do to get it dialed in now may not work next winter when you get the next really cold day, but you can further tune it then.

It's much tougher to manually dial in the curve when you have multiple zones. That said, just keep lowering the water temp at the 68° ODT until you can no longer maintain comfort (I'd be tempted to leave the cold end of the curve alone until it's cold out).

I say comfort because if you are using setback, the excess capacity it requires will ultimately result in the zone not being able to recover in a timely fashion. At that point, you'll have to decide if you want to do less setback, start it sooner or give up on it or stop dropping the curve. If there is no setback, at some point, one of your zones will be unable to stay at temp.

You might want to try physically plotting out the curve, so that you can compare different efforts. I made a <a href="http://boilerbuff.com/forum/index.php?action=dlattach;topic=87.0;attach=344">spreadsheet</a>
to help in doing this and you could put your four data points in it so that you can visualize the curve and also know what temperature your water should be at any given ODT.

I dialed in my curve this past winter and it took a good week and that was with a single zone, a wide range of varying outdoor temperatures, and using pure ODR (all making it much easier). For you it'll take longer and your adjustments will have to be monitored for each zone.

There's not much difference in efficiency between having a curve that is close to ideal and bang on - you've made the most improvement just dropping the maxT to 145°.

Jeff Lewis

I am looking for any suggestions for setting the central heating curve on a Munchkin 199 w/ Vision 1 system. It powers a staple up radiant system with multiple zones. Floor coverings range from concrete slab in the basement to wood on the 1st floor and carpet on 2nd floor. We need to be careful no to overheat the wood floor, but we also have carpet as an insulator in some zones. No mixing valves are in use right now.

Factory default heating curve is 201 degree supply at 5 degree outdoor temp, down to 95 degree supply at 68 degree outdoor temp. For now the max supply temp is set around 145 to avoid overheating some floors.

We are in the midwest where winter temps range 0 to 30 December through February, with colder wind chills at times.

Any suggestions are welcome.

- Jeff

jp_2

don't see

how you can run a cement floor and a carpet floor together and be happy with the results?

ALH_4

Mixing Valve

Sounds like you need a mixing valve to run the concrete on a separate curve. There is no single curve that will provide satisfactory heating with concrete and carpet. If it is bare tube staple up or suspended tube, you *might* run the hardwood foors at the same temp as the carpet. If there are extruded aluminum plates under the hardwood, you might run it at the same temp as the concrete. Or you might run it on its own temp. I think you might need 3 different temperatures in order to provide proper operation because of the widely varying floor coverings.

Carpet is not a good mix with radiant floors in general. It can work, but usually not in colder climates without supplemental heat. You might install a few panel radiators in the carpeted carpeted floor will need much hotter temperatures than the hardwood or concrete.

Unknown

If you don't have a heat load calc, you're guessing. Do the math.

You'll probably need to mix a 2nd temp as well. Though it might be ok, depending, to just limit the slab temps with a 3-way tempering valve and set the curve for the joist heating.

Glenn Sossin_2

Chart

Very impressive chart. Have put into my reference collection

Jeff Lewis

We've only been through one heating season, but it was great this past year. The different floor types are on different zones, so the system seems to handle the heat loss and insulation factors pretty well that way.

Jeff Lewis

Great help. The spreadsheet is well done. Thanks very much.