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Author Topic: Pressurize a HEATMOR?  (Read 4435 times)

jgrosh

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Pressurize a HEATMOR?
« on: January 07, 2017, 10:01:19 AM »

I bought  a used 200CSS, about ten years old. I'm tying it into my oil boiler in the basement. System pressure in the house system runs at about 25psi.
I know that HEATMOR says the furnace cannot be pressurized. I'm wondering if anyone has tried pressurizing any of these units? What would fail, if anything?

If anyone has successfully pressurized one of these jackets, I'd love to hear about it. Warranty issues don't apply so much to me since my furnace is old and I'm not the original purchaser. I'd love to send my house system water straight out to the HEATMOR, just like I did with my old stove, which was a homemade job with a little less capacity than the 200CSS. I'm not relishing installing the water-to-water heat exchanger and the additional circulator.

If it's absolutely clear that bad things will happen if I pressurize the 200CSS, then can anyone help with suggestions on flat plate exchanger sizing and a good brand for price? My loop from OWB to oil boiler is about 160 feet total in 1 1/4" copper and I need to transfer about 150--200K BTU/H.

--John
south-central Pennsylvania
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John Grosh

RSI

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Re: Pressurize a HEATMOR?
« Reply #1 on: January 07, 2017, 10:09:08 AM »

Pressurizing it is a very bad idea. The water jacket isn't made for it and would likely fail right away.
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jgrosh

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Re: Pressurize a HEATMOR?
« Reply #2 on: January 07, 2017, 12:29:31 PM »

I'm curious how the water jacket would fail. Would the pressure warp the metal? Would it leak?

What do the furnaces that are designed for pressure have that the others don't?

--John
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John Grosh

hondaracer2oo4

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Re: Pressurize a HEATMOR?
« Reply #3 on: January 07, 2017, 12:45:01 PM »

There was someone over at hearth forum that tried to use two 275 home heating oil tanks for storage in his basement 10 feet below his owb. The 5 psi that the water gained from the owb caused the tanks to bow out and was in danger of failing.
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mlappin

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Re: Pressurize a HEATMOR?
« Reply #4 on: January 07, 2017, 02:28:35 PM »

It doesn’t take but a few pounds to cause a 55 gallon drum to fail, I used to pressurize em to force cold waste oil out of em in the dead of winter, never had one blow, but also wasn’t usable again.

Pressurized boilers are designed for pressure, most OWB that are a open system aren’t, the shape of it plays a large part and the thickness of the metal plays a BIGGEST part, pressurized boilers may also have stay pins welded in between the firebox and water jacket to help prevent bowing.
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RSI

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Re: Pressurize a HEATMOR?
« Reply #5 on: January 07, 2017, 03:21:48 PM »

It doesn’t take but a few pounds to cause a 55 gallon drum to fail, I used to pressurize em to force cold waste oil out of em in the dead of winter, never had one blow, but also wasn’t usable again.

Pressurized boilers are designed for pressure, most OWB that are a open system aren’t, the shape of it plays a large part and the thickness of the metal plays a BIGGEST part, pressurized boilers may also have stay pins welded in between the firebox and water jacket to help prevent bowing.

I tried the same thing. End bulges out and they tip over. Wouldn't take much more pressure to peel the crimp open.

The flat areas of a firebox and outside of the water jacket will not take more than a few PSI before they are bulging. A boiler has to be designed to take pressure.

Either de-pressurize the indoor system or use a plate exchanger. if you have 1-1/4" copper piping then I would probably just use a 100 plate. Will have less restriction and not that much more expensive.
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fireboss

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Re: Pressurize a HEATMOR?
« Reply #6 on: January 07, 2017, 03:39:13 PM »

You have to put a heat  exchanger in between to keep the two of them separate
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jgrosh

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Re: Pressurize a HEATMOR?
« Reply #7 on: January 08, 2017, 04:18:48 PM »

Thanks for the feedback. I suppose I will have to install the flat plate heat exchanger.

RSI mentioned the possibility of depressurizing the house system. But won't the fact that I have a two-story house with radiators on the second floor generate pressure in the system at the lower floors? I'm thinking of the weight of the water column. (Perhaps that only applies if an upper-floor radiator were opened up to allow air into the system?)

--John
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John Grosh

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Re: Pressurize a HEATMOR?
« Reply #8 on: January 08, 2017, 06:15:06 PM »

Before I bought the boiler I have now I thought about doing the same thing you are talking about. With the original set up I was looking at you could go either way. I'm glad I went with the flat plate in that now I have 2 seperate systems that can run as designed independently. I have 11/4" copper in the house and I used a 70 plate with 11/4" ports as I wanted about 200,000 btu. I couldn't be happier. The heat exchange is plenty for a quick recovery when zones call for heat or to heat my dhw. It takes an extra circulator but it doesn't need to be very big. I have a taco 007 and it does just fine. Maybe someone can correct me if I'm wrong but isn't the idea of a pressurized system to keep air out?
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Re: Pressurize a HEATMOR?
« Reply #9 on: January 08, 2017, 06:52:46 PM »

Thanks for the feedback. I suppose I will have to install the flat plate heat exchanger.

RSI mentioned the possibility of depressurizing the house system. But won't the fact that I have a two-story house with radiators on the second floor generate pressure in the system at the lower floors? I'm thinking of the weight of the water column. (Perhaps that only applies if an upper-floor radiator were opened up to allow air into the system?)

--John

With a system like that you want to keep it pressurized.
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hondaracer2oo4

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Re: Pressurize a HEATMOR?
« Reply #10 on: January 08, 2017, 09:17:45 PM »

Air out and corrosion to a minimum.
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