Heat master g100

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logfarmer

Feeling the Heat
Oct 25, 2015
258
Ohio
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.
 
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.
 
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?
 
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.
 
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.
 
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
 
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
 
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.
 
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.
 
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.
 
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.
 
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
 
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.
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?
 
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.
 
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.
 
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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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?
 
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!
 
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.
 
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?
 
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.