merging two zones...issues?

R. Kalia

I am thinking about having our contractor merge the two zones in our house into one. Since the people here know much more than our contractor does, I am hoping you will be kind enough to give me some tips.

We have a primary zone with mostly radiators, and a small zone with mostly baseboard. Looking at the call-for-heat times tallied by each thermostat, there is not a big difference...one zone calls for heat longer when the sun is shining, the other calls for heat longer when the sun isn't shining. (Obviously one zone is to the south, the other to the north.)

So I would prefer to have the 2 zones merged (one pump, one thermostat) when I upgrade the boiler to condensing with continuous flow. Any problems with this? For example, will the relative water flow to the two zones change when there is only one pump rather than 2, thus causing one zone to become colder than others? How does one go about balancing this? (Can I use TRVs on the baseboard? I didn't think one could. Also, I don't know which area will get colder, and TRVs will only work in the area that is hotter when the valves are wide open.)

In general, say in new construction, when connecting various radiators and baseboard units, some in parallel and some in series with each other, how does one make sure that the right amount of heat is being delivered to each room? How does one pick the right circulator?

Is there a book that covers this stuff?

R. Kalia

looking for some pointers

I am thinking about having our contractor merge the two zones in our house into one. Since the people here know much more than our contractor does, I am hoping you will be kind enough to give me some tips.

We have a primary zone with mostly radiators, and a small zone with mostly baseboard. Looking at the call-for-heat times tallied by each thermostat, there is not a big difference...one zone calls for heat longer when the sun is shining, the other calls for heat longer when the sun isn't shining. (Obviously one zone is to the south, the other to the north.)

So I would prefer to have the 2 zones merged (one pump, one thermostat) when I upgrade the boiler to condensing with continuous flow. Any problems with this? For example, will the relative water flow to the two zones change when there is only one pump rather than 2, thus causing one zone to become colder than others? How does one go about balancing this? (Can I use TRVs on the baseboard? I didn't think one could. Also, I don't know which area will get colder, and TRVs will only work in the area that is hotter when the valves are wide open.)

In general, say in new construction, when connecting various radiators and baseboard units, some in parallel and some in series with each other, how does one make sure that the right amount of heat is being delivered to each room? How does one pick the right circulator?

Is there a book that covers this stuff?

Uni R

Merging Zones

How are the two zones currently piped?

R. Kalia

piping

The first zone has a pipe going from the boiler to a circulator pump, after the pump then the piping splits into several pipes and up to the radiators; returns the same way.

The second zone has its own circulator pump, then the piping splits into several pipes etc etc.

This seems rather obvious so I am probably not answering your question. Please ask more specifically, remember I am only a homeowner!

Uni R

piping

Nothing wrong with being "only a homeowner"... I am as well. Your zones might be loops. The water comes out of one rad and then goes to the next rad in the system and so on until it gets to the end of the zone. It could also be parallel or parallel reverse return. With this layout a feeder pipe has branches on it that supplies all of the radiators. Likewise there is a collector pipe that all of the radiators dump into and this completes the zone. If the collector runs in the opposite direction then it is called a reverse return. Also, there are diverter tee (monflo) systems. One pipe runs around the zone and it has special tees on it that branch off to and return from each radiator. Was your system ever a single zone? If so, then it could probably be reverted.


You might want to read http://www.heatinghelp.com/heating_qa.cfm and look at loop and diverter tee layouts.


The layout of the piping will greatly impact whether or not you can "unzone" your system. If your kitchen/eating area is the other zone I would leave it as a separate zone. Some people like everything zoned, but I prefer the simplicity of the house being one zone. However, if one room ever warrants a zone of its own it's the kitchen, especially if the t-stat is anywhere in its vicinity.

R. Kalia

ah, ok

> parallel reverse return. With this layout a

> feeder pipe has branches on it that supplies all

> of the radiators. Likewise there is a collector

> pipe that all of the radiators dump into and this

> completes the zone. If the collector runs in the

> opposite direction then it is called a reverse

> return.


The big zone is parallel reverse return (formerly gravity); the small (kitchen) zone is parallel.

But that's not entirely true, because some of the lines have more than one unit on them (in series).

> Was your system ever a single zone?


No.

> layout of the piping will greatly impact whether

> or not you can "unzone" your system. If your

> kitchen/eating area is the other zone I would

> leave it as a separate zone. Some people like

> everything zoned, but I prefer the simplicity of

> the house being one zone.


I do too. What's special about the kitchen?

Uni R

Kitchen

So it's supper time... A huge pot of pasta boiling on the stove, another pot of asparagus is steaming, plus a meat sauce simmering on the stove while the garlic bread is being warmed up in a 400° oven. Everyone is in and around the kitchen. Meanwhile outside the sun's gone down and it is cooling off very rapidly outside. Too bad that the only t-stat is in between the kitchen and the dining room. The t-stat says it is more than warm enough. It's now 73 and you have it set for 68. It turns into a fairly late dinner and by 8pm the thermostat is still happy with the heat of everyone sitting there. Then the evening setback kicks in dropping the t-stat to 65. Then you go to the livingroom and its already dropped to 65 (and feels even colder since you've just eaten) and the temperature will stay that way because the set back has kicked in for the night... That's the special nature of kitchens in long form.


The other scenario is even though it's 73 in the kitchen, the rest of the house is cold and since the t-stat is there it kicks out more heat for the house. Even the kitchen that doesn't need it.

R. Kalia

TRVs

The answer to a too-warm kitchen is TRVs, not a separate zone. Our kitchen has baseboards, but there must be a way to put TRVs on them.

Uni R

Yup

There are TRVs with remote sensors.

lchmb

question

for the minor cost involved to have the second zone and the cost associated with swapping it to a single zone, why would you? Believe it or not, the cost of that second zone opening and running is pennies. Just wondering why you want to remove it?

R. Kalia

reason for one zone

I want to run the boiler such that the circulator is wired to run all the time. The thermostat will turn the burners on/off but not the circulator; only the summer/winter switch will turn off the circulator.

This doesn't work with more than one thermostat.

Uni R

Zones

How is the house zoned now? Which rooms?

R. Kalia

rooms

Kitchen and BR above it are smaller zone. LR,DR,FR,3BR are larger zone. Why?

Tombig_2

A very basic

solution is to just run both pumps from one control. You'll have to see how your existing piping jives with your new condensing boiler.Pri-sec with all pumps continuous?