# Heat master g100



## logfarmer (Dec 13, 2019)

I’m looking into the heat master g100 boiler and have a few questions for you experts out there! House is 1800 sq ft 2 story, built in 1983,(900 sq ft per floor) moderately insulated, new windows. I have a propane air forced unit that does the main floor, and a separate system for the 2nd floor which is a heat pump with electric back up heat. 2nd floor never had heat/air when we bought the house, just installed it upstairs 2 yrs ago. Now, would I run the pex pipe up the back of the house like my line set is for the upstairs unit? Insulated of course! But I will also be building a 1200 sq ft garage right next to the house that I wouldn’t mind running heat into either. Would I be asking too much from the 100 series to do this? Would be 3000 sq ft total and would like to heat water along with it. I live in southwest Ohio. Thank you for any info I receive.


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## Medic21 (Dec 13, 2019)

logfarmer said:


> I’m looking into the heat master g100 boiler and have a few questions for you experts out there! House is 1800 sq ft 2 story, built in 1983,(900 sq ft per floor) moderately insulated, new windows. I have a propane air forced unit that does the main floor, and a separate system for the 2nd floor which is a heat pump with electric back up heat. 2nd floor never had heat/air when we bought the house, just installed it upstairs 2 yrs ago. Now, would I run the pex pipe up the back of the house like my line set is for the upstairs unit? Insulated of course! But I will also be building a 1200 sq ft garage right next to the house that I wouldn’t mind running heat into either. Would I be asking too much from the 100 series to do this? Would be 3000 sq ft total and would like to heat water along with it. I live in southwest Ohio. Thank you for any info I receive.


Yes, you need a G200 for that heat load.  I believe @E Yoder may be a dealer or installer for Heatmaster.  I have a Crown Royal but, the Heatmaster is just as good a unit, good choice.


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## E Yoder (Dec 14, 2019)

I am a HeatMaster dealer. 3000 sq ft is for heating one well insulated building. 3 different blowers in a moderately insulated building(s) sounds like it will stretch the G100. I'd agree that a G200 would be a better fit, unless you don't mind 8-12 hour burn times (between loading). 
Keeping the garage turned down to maybe 50° most of the time might allow you to get by with a 100. 
I've run insulated piping up the side of the house. I'm more concerned about the heat exchanger freezing than I am the pex piping. Insulate the heat exchanger very well and you should be fine. I'm assuming there are no closets inside to run piping up through?


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## ChemicalWaste (Dec 17, 2019)

I have the opposite setup with a heat pump downstairs installed 3 or 4 years agao and forced air gas in the attic, but a poorly insulated 3300 sqft house built in 1873 with original windows and 12 foot ceilings downstairs and 10 ft upstairs. Looks cool until you have to heat that empty space.

Anyway, I had a place to run the pex to the attic from inside. Eventually i will build a bulkhead around it so its not so unsightly, but the heat is at least in the house. My HX hasnt frozen yet and its in an unconditioned attic. And im heating the whole place with a GS200. It provides plenty of heat for generally 10-16 hours depending on weather. Tonight, its having a fit for some reason. Still heating the house, but we're mad at each other right now.


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## maple1 (Dec 18, 2019)

ChemicalWaste said:


> I have the opposite setup with a heat pump downstairs installed 3 or 4 years agao and forced air gas in the attic, but a poorly insulated 3300 sqft house built in 1873 with original windows and 12 foot ceilings downstairs and 10 ft upstairs. Looks cool until you have to heat that empty space.
> 
> Anyway, I had a place to run the pex to the attic from inside. Eventually i will build a bulkhead around it so its not so unsightly, but the heat is at least in the house. My HX hasnt frozen yet and its in an unconditioned attic. And im heating the whole place with a GS200. It provides plenty of heat for generally 10-16 hours depending on weather. Tonight, its having a fit for some reason. Still heating the house, but we're mad at each other right now.



Is there anything at all you can do to get your heating equipment out of the attic? That seems to have you lined up behind an 8 ball right off the bat - I know it gets done sometimes, but it just makes no sense to me at all to put heating equipment in an unheated attic. Just the simple heat always wants to rise physics of it all is bad enough to work against, let alone also trying to do it in an unheated space. Just wondering if since you got some pipes run up there, you could run some pipes up to the upper level to feed some rads or not.


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## logfarmer (Dec 19, 2019)

Thank you all for the info! E Yoder, I have no interior closets that line up with each other from downstairs to upstairs. I “could” build a chase to go inside the house if I really need too, would have to ask the “boss” on that tho, since it would be ran up thru our room! My first thought on the 100 boiler would be I would only use heat in the garage when I need to work out there or for a party or two in the colder months and not really heat it much, but if I go with the 200 I might as well keep heating it just leave the thermostat set like said at 50 or so would be just fine. I use a wood stove for our primary heat(downstairs) that is now. I just started reading about these boilers last wk and it made me think it would be nice to heat the whole house “evenly” from one unit and really not have to use the electric back up heat upstairs due to it cost a pretty penny when it is needed. Yesterday our high temp was 23*f and the house lost one degree about every 1 hr with 10-20 mph winds. I feel the house has decent insulation but to some, maybe not. Underground pipe, does it matter using thermo pex or logstor? I’m not gonna go cheap on that for sure. Any guess on price per ft with either? Thank you


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## logfarmer (Dec 19, 2019)

Another note, I thought the water continuously circulates thru the heat exchangers even when it doesn’t call for heat? I could be wrong, all new to me how these outdoor boilers work. Thanks


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## 3fordasho (Dec 19, 2019)

logfarmer said:


> Another note, I thought the water continuously circulates thru the heat exchangers even when it doesn’t call for heat? I could be wrong, all new to me how these outdoor boilers work. Thanks



I think most people circulate water continuously and turn the fan on/off as necessary to satisfy the thermostat.  I've tried it both ways and found that if you only run the circulator(s) during a call for heat you need a couple minute delay for the blower fan to allow hot water to get to the heat exchanger (depending on circulator flow and piping distance). Constant circulation prevents freeze ups so in my case I run some glycol in my loop to the house.   Freeze ups may not be an issue if your lines are deep enough.  Right now I'm experimenting with running the circulators full time and find that when the blower fan is not running I'm putting about 9kbtu/hr into the house just through natural convection through the duct work and the floors seem to be a bit warmer as well.  I still have not decided which method is best for me.   There is some energy savings by only running the circulator(s) during a call for heat but in my case both circulators are on low speed and only draw 8 watts each.   

I work with a guy that runs a older OWB and swears he cut his wood consumption down by only running the circulator during calls for heat.  I don't know what he has for underground lines but probably the cheap stuff - corrugated tubing with the wraps of foil insulation between the pex lines.


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## 3fordasho (Dec 19, 2019)

logfarmer said:


> Underground pipe, does it matter using thermo pex or logstor? I’m not gonna go cheap on that for sure. Any guess on price per ft with either? Thank you



I think both are good, another to look at is Rehau.  Just make sure you know what the true inside diameter is.  Some listed as 1" is not 1" id and some is.  I don't think you want to go less than 1" true id but that depends on your heat load, distance of piping, and circulator pump.  Sometimes 1 1/4" is required.  Central boiler is selling a newer version of thermopex that is cheaper and more flexible - less insulation however.

I went foam in trench and 1" pexalpex and performance seems good so far, I continuously monitor temps on both ends.  There are lots of ways to screw up foam in trench so beware of that and I went into it knowing the risk and the possibility of redoing it later if water penetrates it at some point.

I've seen the Rehau for ~11-12$ per foot from an outfit in Wisconsin, shipping was about $300 however.  I've seen the Central boilers new version of thermopex for 8-9$ per foot. (the more flex less insulation version)

buyer beware on underground piping.


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## Medic21 (Dec 19, 2019)

logfarmer said:


> Another note, I thought the water continuously circulates thru the heat exchangers even when it doesn’t call for heat? I could be wrong, all new to me how these outdoor boilers work. Thanks



with a G Series if you don’t run the circulatorall the time you will have to run a shunt pump. Chances are you may still need one.

As far as lines.  Any closed cell foam. Stay away from the new 25mm Thermopex as it will not be big enough for anything.  Your dealer should have the new stuff from Heatmaster, like I said closed cell Foam only.  The wrap crap is worthless and you will have to do it over eventually.


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## ChemicalWaste (Dec 19, 2019)

maple1 said:


> Is there anything at all you can do to get your heating equipment out of the attic? That seems to have you lined up behind an 8 ball right off the bat - I know it gets done sometimes, but it just makes no sense to me at all to put heating equipment in an unheated attic. Just the simple heat always wants to rise physics of it all is bad enough to work against, let alone also trying to do it in an unheated space. Just wondering if since you got some pipes run up there, you could run some pipes up to the upper level to feed some rads or not.


It's in the cards to insulate the attic. There really isn't a great way to solve the issues other than to turn the attic into conditioned space, which won't be hard, it's just not the top priority right now. It had a worse effect for ac in the summer than heat in the winter i think, but they're both terrible.


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## logfarmer (Dec 19, 2019)

Medic21 said:


> with a G Series if you don’t run the circulatorall the time you will have to run a shunt pump. Chances are you may still need one.
> 
> As far as lines.  Any closed cell foam. Stay away from the new 25mm Thermopex as it will not be big enough for anything.  Your dealer should have the new stuff from Heatmaster, like I said closed cell Foam only.  The wrap crap is worthless and you will have to do it over eventually.


Thank you for explaining the pumps running or not. I could probably get away with convection on mild days myself


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## logfarmer (Dec 19, 2019)

3fordasho said:


> I think both are good, another to look at is Rehau.  Just make sure you know what the true inside diameter is.  Some listed as 1" is not 1" id and some is.  I don't think you want to go less than 1" true id but that depends on your heat load, distance of piping, and circulator pump.  Sometimes 1 1/4" is required.  Central boiler is selling a newer version of thermopex that is cheaper and more flexible - less insulation however.
> 
> I went foam in trench and 1" pexalpex and performance seems good so far, I continuously monitor temps on both ends.  There are lots of ways to screw up foam in trench so beware of that and I went into it knowing the risk and the possibility of redoing it later if water penetrates it at some point.
> 
> ...


I wonder if I will have to go up to 1-1/4” pipe to get to the 2nd floor of my house from the ground? Not sure if 1” will be big enough, I don’t know! Or I might have to use a bigger pump?


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## Medic21 (Dec 19, 2019)

logfarmer said:


> Thank you for explaining the pumps running or not. I could probably get away with convection on mild days myself



it’s not an option on the gassers.  A shunt  pump is required.  Sometimes the main circulator is adequate, usually not.


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## Medic21 (Dec 19, 2019)

logfarmer said:


> I wonder if I will have to go up to 1-1/4” pipe to get to the 2nd floor of my house from the ground? Not sure if 1” will be big enough, I don’t know! Or I might have to use a bigger pump?



how many BTUs will you be needing?  I run 1 1/4” on my setup with a primary/secondary loop only because I pull domestic hot water, 110,000btu to heat the house and a 50,000btu heater in my garage.  Im right at the edge of 1” capabilities with adding the garage heater.  I wanted room to expand later if I wanted to.


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## maple1 (Dec 19, 2019)

logfarmer said:


> I wonder if I will have to go up to 1-1/4” pipe to get to the 2nd floor of my house from the ground? Not sure if 1” will be big enough, I don’t know! Or I might have to use a bigger pump?



They aren't related. Pipe size depends on how much btus you need to move from boiler to load.


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## E Yoder (Dec 20, 2019)

A single air handler typically can be heated with a ¾" line as a secondary loop. It's easier to purge air out from a high attic loop. Larger piping would be a lot harder. 
I usually pipe something like you have with a larger continuous primary loop through the flat plate heat exchanger. Then pump secondary loop(s) off to the air handlers that start and stop with each call for heat.  A mixing (shunt) pump on the boiler will mix the return water so return water temps aren't an issue. With that in place I typically aim for a larger temp drop  (Delta t) on the main loop than people do with copper baseboard systems which aim for 20F, forced air is much more forgiving. 
Heatmaster has the Rhinoflex pipe that's a solid foam filled pipe, similar to thermopex/rehau.


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## logfarmer (Dec 20, 2019)

Medic21 said:


> how many BTUs will you be needing?  I run 1 1/4” on my setup with a primary/secondary loop only because I pull domestic hot water, 110,000btu to heat the house and a 50,000btu heater in my garage.  Im right at the edge of 1” capabilities with adding the garage heater.  I wanted room to expand later if I wanted to.


I honestly don’t know how many BTUs I’ll need. Isn’t there a formula for that?


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## Medic21 (Dec 20, 2019)

logfarmer said:


> I honestly don’t know how many BTUs I’ll need. Isn’t there a formula for that?


How many btu is your furnace and how big of a heat exchanger will you be using?


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## logfarmer (Dec 20, 2019)

Medic21 said:


> How many btu is your furnace and how big of a heat exchanger will you be using?


I figured it out, need 70k btus for the house.


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## Medic21 (Dec 20, 2019)

logfarmer said:


> I figured it out, need 70k btus for the house.


Are you saying your furnace it 70k?  Do you plan on running a plate exchanger for domestic hot water?


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## logfarmer (Dec 20, 2019)

Medic21 said:


> Are you saying your furnace it 70k?  Do you plan on running a plate exchanger for domestic hot water?


Well I have the 2 units, 1st floor is 35k btu and I actually think the unit upstairs is smaller I will have to check at some point. I do plan on heating the water also. At this point I do not know the sizes of the exchangers I will need for the units or water heater, I haven’t made it that far. Just trying to collect as much info as I can now. Sorry I do feel like an idiot about this stuff and asking these questions!


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## Medic21 (Dec 20, 2019)

logfarmer said:


> Well I have the 2 units, 1st floor is 35k btu and I actually think the unit upstairs is smaller I will have to check at some point. I do plan on heating the water also. At this point I do not know the sizes of the exchangers I will need for the units or water heater, I haven’t made it that far. Just trying to collect as much info as I can now. Sorry I do feel like an idiot about this stuff and asking these questions!


Not at all.  That’s where we all were at one point.  

1 inch Thermopex or any of the closed cell line sets should be enough.  You will want to go to the plate exchanger first then two the furnaces.  with the house and garage you may want to look at a primary secondary loop system or run a separate line to the garage.


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## logfarmer (Dec 20, 2019)

Medic21 said:


> Not at all.  That’s where we all were at one point.
> 
> 1 inch Thermopex or any of the closed cell line sets should be enough.  You will want to go to the plate exchanger first then two the furnaces.  with the house and garage you may want to look at a primary secondary loop system or run a separate line to the garage.


The plate exchanger is for the water heater correct? I wonder if it will be better to just do a separate run to the garage?


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## Medic21 (Dec 20, 2019)

logfarmer said:


> The plate exchanger is for the water heater correct? I wonder if it will be better to just do a separate run to the garage?



Is the garage attached? It gets real expensive at$12-$15 a foot for lines.

Yes a 20 plate exchanger will supply you with all the hot water you would want.


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## E Yoder (Dec 21, 2019)

If the garage is attached a secondary loop through the house is most likely a lot cheaper. 
If you pipe it with domestic water first, downstairs air handler, upper air handler, garage it should work fine. Garage blower will occasionally blow cool air but you'll never notice.


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## logfarmer (Dec 21, 2019)

Medic21 said:


> Is the garage attached? It gets real expensive at$12-$15 a foot for lines.
> 
> Yes a 20 plate exchanger will supply you with all the hot water you would want.


The garage will not be attached, depending on which side of the house  we build on it will be 15’ away or 25’ away.


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## logfarmer (Dec 21, 2019)

Ok I need to clear this up, how does a “loop” work with theses boilers. Would it be a line set feeds the downstairs unit then go to upstairs unit, then back to the boiler? I feel I’m over thinking this


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## Medic21 (Dec 22, 2019)

logfarmer said:


> Ok I need to clear this up, how does a “loop” work with theses boilers. Would it be a line set feeds the downstairs unit then go to upstairs unit, then back to the boiler? I feel I’m over thinking this



the big pipe is the primary loop and the pumps are in the secondary loops. Primary just circulates back to boiler.


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## maple1 (Dec 22, 2019)

Closely placed Ts being a critical detail...


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## Medic21 (Dec 22, 2019)

And, depending on where your boiler is placed you can use the Thermopex from the house to the garage if it’s closer.  Save some money.


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## logfarmer (Dec 22, 2019)

Medic21 said:


> the big pipe is the primary loop and the pumps are in the secondary loops. Primary just circulates back to boiler.
> 
> View attachment 253949


That looks very nice!! Did you do that yourself?


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## logfarmer (Dec 22, 2019)

Medic21 said:


> And, depending on where your boiler is placed you can use the Thermopex from the house to the garage if it’s closer.  Save some money.


Well I was wondering if You could just go from the house out to the garage! That would save some money in one location that I might build the garage.


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## Medic21 (Dec 22, 2019)

logfarmer said:


> That looks very nice!! Did you do that yourself?


Yes


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## E Yoder (Dec 24, 2019)

logfarmer said:


> Ok I need to clear this up, how does a “loop” work with theses boilers. Would it be a line set feeds the downstairs unit then go to upstairs unit, then back to the boiler? I feel I’m over thinking this


This might sound too elementary but it's a way of thinking I learned from Dan Holahan- Think of it as a train carrying degrees F in, dropping them off using a heat exchanger, then traveling back empty to refill at the boiler/ OWB. Two ways to move heat, move the train faster or drop off more degrees F, depending on the type of heating system you would aim to use one method or the other (or a combination realistically). 
A primary loop typically circulates all the time from the OWB to the house at a higher volume (enough to supply the typical heating load at a cold day) the secondary loops pull off the main loop using supply and return tees as needed to heat your house. Typically starting and stopping flow with each call for heat from the thermostat. 
There are various ways to do it, but I usually pump the primary loop through the hot water heat exchanger since I want it hot all the time anyway, then pump a secondary loop (using close tees as in the picture) through the bottom, then the top air handler. By doing one secondary loop the top loop has less chance of freezing since it circulates when the bottom air handler runs. 
It takes several relays, but isn't terribly difficult to wire.


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## Medic21 (Dec 24, 2019)

I simplified mine.  My secondary pumps run all the time.  First one is the hot water exchanger and the others are heat exchangers for the forced air systems.  One is in the garage so I didn’t want it to freeze if we shut off the heat.  

The 15-58 pumps don’t use much electricity on the first setting.


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## Medic21 (Dec 24, 2019)

simple drawing. The concept is pushing enough BTUs into the house. BTUs is gpm. Let’s say you move 10gpm and have a 20 degree delta t. That’s roughly 100000 BTUs. The reason to use a primary/secondary system is to allow the efficient use of those BTUs.

what goes into the first tee for a load has to come back out the second tee. So if you take 5 gpm out there is still 5 gpm going through the section between tees. After the load takes the BTUs it needs it mixes back into the 5gpm water at 180 degrees leaving the rest for the next load.  

my primary loop is 1 1/4” ID pex and 1 1/2” copper with 1” copper loads. The whole reason is 1” pex would not deliver enough BTUs for the load I have on it in the house. If I ran 2 1” line sets I could have done it that way. This is more efficient to handle the load and cheaper based on the cost of Thermopex.

my system is overkill based on the ability to expand it into a floor heat later if I desire.  I can push more BTUs than my furnace is capable of so if I ever swap it for a larger one the piping is there. I plan on building a larger shop with floor heat in the future so I designed the system to handle that from the house.


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## logfarmer (Dec 25, 2019)

E Yoder said:


> This might sound too elementary but it's a way of thinking I learned from Dan Holahan- Think of it as a train carrying degrees F in, dropping them off using a heat exchanger, then traveling back empty to refill at the boiler/ OWB. Two ways to move heat, move the train faster or drop off more degrees F, depending on the type of heating system you would aim to use one method or the other (or a combination realistically).
> A primary loop typically circulates all the time from the OWB to the house at a higher volume (enough to supply the typical heating load at a cold day) the secondary loops pull off the main loop using supply and return tees as needed to heat your house. Typically starting and stopping flow with each call for heat from the thermostat.
> There are various ways to do it, but I usually pump the primary loop through the hot water heat exchanger since I want it hot all the time anyway, then pump a secondary loop (using close tees as in the picture) through the bottom, then the top air handler. By doing one secondary loop the top loop has less chance of freezing since it circulates when the bottom air handler runs.
> It takes several relays, but isn't terribly difficult to wire.


Thank you EYoder, makes since to me now. Have a merry Christmas.


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## logfarmer (Dec 25, 2019)

Medic21 said:


> View attachment 254074
> 
> 
> simple drawing. The concept is pushing enough BTUs into the house. BTUs is gpm. Let’s say you move 10gpm and have a 20 degree delta t. That’s roughly 100000 BTUs. The reason to use a primary/secondary system is to allow the efficient use of those BTUs.
> ...


That drawing is what I needed for sure now it clicks in my head. Thank you for answering my silly questions. Have a merry Christmas


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## Medic21 (Dec 25, 2019)

logfarmer said:


> That drawing is what I needed for sure now it clicks in my head. Thank you for answering my silly questions. Have a merry Christmas


You’re welcome.  Like I messaged you your more than welcome to come and look at my setup, I got a buddy close also that has a different style of setup also.  Anytime you want.

Merry Christmas!!


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