Heating my garage with a boiler

[paco_06]

Well, the bad thing is that I don't necessarily think 50k is too small for my building, actually I think it would be spot on. According to whatever calculations the seller used, I need 50-60k btu .... Only calculation I used was an actual heater I already have, it's a 75k btu forced air torpedo heaters that runs on kerosene. On the coldest of days, it takes 30 minutes to knock the chill off and about an hour to bring the building up to 50 degrees or so where it's comfortable.... Honestly, I think the heater I bought is in the 25kbtu range and if my building were 1000sqft it would be more than enough. I'm not sure of the water temperatures, but I know the pipes are hot to the touch and I can't tell that the return is any cooler than the incoming. My water pump is twice the size of the one for my house and half the distance, so all's good there. Unfortunately, this unit only puts off as much air as maybe two vents in my house and my house has eight.

I've talked to the company via email a little and he says they can't take it back in exchange for a larger unit because it's "used" now although nothing has been hurt. I actually added it to the for sale section here to see if I can offer someone a deal. I'll end up getting a 100k unit in the near future and if no one wants the small one, I guess I'll just send it back with instructions where to put it. Lol.

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[NSMaple1]

Well, the bad thing is that I don't necessarily think 50k is too small for my building, actually I think it would be spot on. According to whatever calculations the seller used, I need 50-60k btu .... Only calculation I used was an actual heater I already have, it's a 75k btu forced air torpedo heaters that runs on kerosene. On the coldest of days, it takes 30 minutes to knock the chill off and about an hour to bring the building up to 50 degrees or so where it's comfortable.... Honestly, I think the heater I bought is in the 25kbtu range and if my building were 1000sqft it would be more than enough. I'm not sure of the water temperatures, but I know the pipes are hot to the touch and I can't tell that the return is any cooler than the incoming. My water pump is twice the size of the one for my house and half the distance, so all's good there. Unfortunately, this unit only puts off as much air as maybe two vents in my house and my house has eight.

I've talked to the company via email a little and he says they can't take it back in exchange for a larger unit because it's "used" now although nothing has been hurt. I actually added it to the for sale section here to see if I can offer someone a deal. I'll end up getting a 100k unit in the near future and if no one wants the small one, I guess I'll just send it back with instructions where to put it. Lol.

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I am thinking it's in your water temps. 'Hot to touch' isn't a measure. Anything over 120-130 and you won't be able to hold your hands on it, and that isn't very hot for a W-A HX supply temp. Without accurately measuring temps in & out, it's just guessing. Then second on the list would be flow. (Or, it might all be about the flow, without knowing temps or how much you are flowing). Their design specs are likely based on real hot supply (maybe 180?), and pretty decent flow. Do you have all the specs or a spec sheet? It should by rights give some many BTU/hr at certain supply temp at certain GPM. One or both of which you likely aren't meeting. I doubt it is the HX itself. But you never know...

 

[CUCV]

Exactly, temperature and flow are critical in getting the BTU's out of the air handler. The Air handlers in my house turn the fan on and off when the temp is below 140 degrees. I opted to skip the aquastat in the garage and the fan just runs when that zone is on and calling for heat. I agree the design spec is most likely for 180 degree inlet water with a 20 degree delta T or 160 degree return water temp.

 

[paco_06]

I am thinking it's in your water temps. 'Hot to touch' isn't a measure. Anything over 120-130 and you won't be able to hold your hands on it, and that isn't very hot for a W-A HX supply temp. Without accurately measuring temps in & out, it's just guessing. Then second on the list would be flow. (Or, it might all be about the flow, without knowing temps or how much you are flowing). Their design specs are likely based on real hot supply (maybe 180?), and pretty decent flow. Do you have all the specs or a spec sheet? It should by rights give some many BTU/hr at certain supply temp at certain GPM. One or both of which you likely aren't meeting. I doubt it is the HX itself. But you never know...

Well, the lines for the heater are every bit as hot as the lines for my house. It all comes from the same supply. The heater is half the distance from the boiler as the coil in my house, maybe 25'. And the pump is 1/3 HP where my house has a 1/8hp. Plenty of hot water getting there, it's just not doing anything with it as the return line is as hot as the supply line, which is odd to me.

As I'm typing this, I'm thinking I just need to call them and explain the situation. I probably just have a faulty unit, or at the very least it's misrepresented. I do know this, no way it would make my building 70 degrees, unless it were 60 outside. Lol

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[NSMaple1]

Without actually accurately measuring the temps, you don't really know and are just guessing. Which would likely lead to a wasted call. 140 pipes can likely feel as hot as 160 pipes. And it also doesn't mean the heater is out of spec, if you don't know if you are meeting the specs.

You could call & ask them what the supply specs are, or ask if they could send them to you. But I think I would arm myself with some hard data before calling.

I just checked the EBay link - I bought some stuff from OFS when I re-did my boiler, no complaints from that. But it wasn't a unit heater.

 

[cantoo]

To get the heat you need to move air. If the fans are too small it isn't going to put out heat. Heat going in at 180 and coming out at 175 likely.

 

[NSMaple1]

To get the heat you need to move air. If the fans are too small it isn't going to put out heat. Heat going in at 180 and coming out at 175 likely.

Do you know how many cfms yours are?

 

[CUCV]

A point I intended to make earlier was on my building the radiant floor heat I put in is sized for 80KBTU/h, on that same building several contractors quoted 300KBTU/h total in air handlers (these same contractors quoted radiant install as well) Point being I'm not well versed in sizing air handlers but seems like the contractors quoted much larger units when going that way vs. the heat loss of the building. In my house I have less than 60KBTU/h heat loss but I have qty 2 60KBTU/h air handlers.

 

[cantoo]

NS, they don't list the CFM's on the website, they just say that they are sized to the exchanger.

 

[NSMaple1]

NS, they don't list the CFM's on the website, they just say that they are sized to the exchanger.

OK. I see paco's is rated at 516 cfm so was just looking for a comparison.

Also on re-reading, it sounds like his unit is doing pretty well about what could be expected. Heat loss was calced at 40-60k, and he's got a 50k rated unit. Which should mean it would maintain whatever temp inside was used in the calc. And it sounds like it will do and is doing that. But if it is only sized for heat loss (maintaining), it won't have much left over for raising temps (recovery) and would take a long time to do it. So if raising temps inside on occasion were a concern, something around 1.5 or 2x what was sized for by the calc should likely have been selected.

There was also input from some others on how theirs do in recovering - and I think a lot of those also had infloor going. Huge difference there too.

Sounds like a bigger one or a second one is needed to meet the desired outcome - but it's not the fault of the current one.

 

[paco_06]

OK. I see paco's is rated at 516 cfm so was just looking for a comparison.

Also on re-reading, it sounds like his unit is doing pretty well about what could be expected. Heat loss was calced at 40-60k, and he's got a 50k rated unit. Which should mean it would maintain whatever temp inside was used in the calc. And it sounds like it will do and is doing that. But if it is only sized for heat loss (maintaining), it won't have much left over for raising temps (recovery) and would take a long time to do it. So if raising temps inside on occasion were a concern, something around 1.5 or 2x what was sized for by the calc should likely have been selected.

There was also input from some others on how theirs do in recovering - and I think a lot of those also had infloor going. Huge difference there too.

Sounds like a bigger one or a second one is needed to meet the desired outcome - but it's not the fault of the current one.

Thanks for that! I think you just explained it the best I've heard!

I inspected mine yesterday just to double check there's nothing wrong with it and can't find anything.

I'll go ahead and get a 100k unit, I think I'll be much happier in the long run. My thing is once the water gets there, I want it to be used! Just seems like this heater is sending back too much hot water, which will be great in a smaller building as you wouldn't burn as much wood.... In my case, I feel I'm burning more than I should because it never shuts off.

Maybe you need to be a salesman for this sort of stuff! It's very aggravating that I CALLED beforehand to make sure I was getting the right stuff for my application!!!! Now, guess what, no returns because it's used....

Got any suggestions on a 100k unit for me?

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[NSMaple1]

Thanks for that! I think you just explained it the best I've heard!

I inspected mine yesterday just to double check there's nothing wrong with it and can't find anything.

I'll go ahead and get a 100k unit, I think I'll be much happier in the long run. My thing is once the water gets there, I want it to be used! Just seems like this heater is sending back too much hot water, which will be great in a smaller building as you wouldn't burn as much wood.... In my case, I feel I'm burning more than I should because it never shuts off.

Maybe you need to be a salesman for this sort of stuff! It's very aggravating that I CALLED beforehand to make sure I was getting the right stuff for my application!!!! Now, guess what, no returns because it's used....

Got any suggestions on a 100k unit for me?

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I haven't even had any experience with any unit heater, so can't offer much for other suggestions.

There aren't really any short cuts w.r.t wood consumption. The more heat you want or put into your space, the more wood it will take. If the current one isn't pulling enough heat from the water, a bigger or second one will pull more, which will cost you more wood. I don't think the one you have now is really costing you much wood from running so much, if it isn't pulling out what you want like you say.

Not sure how you have this rigged up though. Is the idea that when the heater isn't being used or setpoint is reach, both the fan & the flow stop? Or does it flow all the time and only the fan is controlled? If it flows all the time, piping losses can cost you wood. Especially if your underground pipe is questionable.

 

[Bstull34]

Well, don’t know if your interested in this set up, but I heat my house, water, and 30x40 shop with mine.

 

[cantoo]

paco, When they are selling them they never take into account that you will open the doors they just calculate how much to heat the area. I bought the 70,000 figuring it would be overkill to maintain the temps I want. I'll just mount the other one and use it only for recovery after the doors are opened. Have you considered just getting a 2nd 50,000 BTU unit and setting it a few degrees below your main one? Running 2 will likely be a little more electricity but not sure how much than running a 100,000 BTU with a bigger fan would be. You already have it.

 

[paco_06]

Well, don’t know if your interested in this set up, but I heat my house, water, and 30x40 shop with mine.

Yes, that's what I have. I already heat my water, house, and now my garage.

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[paco_06]

paco, When they are selling them they never take into account that you will open the doors they just calculate how much to heat the area. I bought the 70,000 figuring it would be overkill to maintain the temps I want. I'll just mount the other one and use it only for recovery after the doors are opened. Have you considered just getting a 2nd 50,000 BTU unit and setting it a few degrees below your main one? Running 2 will likely be a little more electricity but not sure how much than running a 100,000 BTU with a bigger fan would be. You already have it.

Well, I'm about to find out. Lol. Just ordered one. Hopefully their cfm ratings are correct, I'll be going from 516 to 1250, but of course it'll be a little louder. I just figure that going by cost alone, these are just sorta cheap generic heaters. Next closest thing I can find is a 150k that's built a little different, but they're around 800 bucks.

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[NSMaple1]

Yes, that's what I have. I already heat my water, house, and now my garage.

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Does the garage have it's own separate loop?

 

[Bstull34]

Yes, mine does

 

[NSMaple1]

Yes, mine does

Was asking about pacos.

 

[paco_06]

Does the garage have it's own separate loop?

Yes, completely sperate from the house. Thermostat controls both pump and heater fan.

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