Steam boiler - hydro loop - need heat exchanger...JohnNY

Bob Bona_4

I wouldn't use a FP, like MD says, the water's too mucky, and is going to coat the innards with slime. Flushing sounds like good intentions, but won't happen, humans being what we are.

An RH8 will cost you just under 8 bills, no getting around it, but is the better choice.

Lately, I have been re considering this scenario, since I run into this often, and I feel that for all the work and material and potential service issues associated in HX's, I have scrapped that idea and propose small boilers. The costs are almost comparable, and the clients now have many options available for expansion down the road.

JohnNY

Please help.

I need to bring a hydronic loop up 4 stories using the condensate from a steam boiler.
The typically-prescribed arrangement doesn't work in this application as, I believe, the weight of the water is holding the flow valves closed.

An Everhot copper HX is really nice but it costs almost $800. There HAS to be something else!

Any of you recent ISH attendees have any tricks up your sleeves?

Anyone else?
Anyone?

Bueller?


Thanks in advance.


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Brad White_9

John

What is the BTU load and what temperature do you require?

Definitely make it a separate closed loop, sure.

A plate exchanger may be a good bet with good straining upstream and a backwash arrangement, especially if the temperatures are close (e.g. you want 180 degree water with 190 degree condensate).

Overall the $800 does not sound too bad for something with large passages and a proven track record though. Even an indirect will set you back at least that much I would think, and take up more space. If you are talking one small room that is another matter but you still have to spend something...

Unknown

Is there

a coil port in the boiler ? If not , what about an inexpensive indirect ? I'm not sure about prices but I think a budget tank can be had for considerably less than that sidearm coil . We've used tha Phase 3 line on a few jobs for hot water heat and it worked good .

Ken_40

Absolutely.

Phase III or W/M Plus? Either way, you should be in good shape with that configuration.

JohnNY

I'm looking for...

...170 degrees in my hydronic loop energized by 190 degree condensate.
I need about 10,000 BTUs total.
Unfortunately, there is no coil port.

Thanks guys.



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Mark Hunt

How about


a flat plate HX?

Mark H

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Brad White

For that load

a small brazed plate exchanger would be ideal IMHO. Just put a good strainer and a dirt air separator upstream on the condensate side and if you are ambitious, back-wash ports (drain valves) inside the isolation valves. For the 1.0 GPM you seek, small potatoes.

EDIT: Mark types faster and with fewer words

Mark Hunt

It ain't easy


with a glass of Dewars!

Mark H

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JohnNY

I'm nervous...

...using a flat plate with a steam boiler.

Would a strainer on the inlet of my pump cause cavitation and premature pump failure?

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Mark Hunt

Here ya' go John


CLICK HERE!

Mark H

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Mark Hunt

I have

never had that problem.

Mark H

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JohnNY

Freakin'...

...sweet.

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Brad White

Done all the time

Your typical wye strainer has little resistance. If in doubt go up a size. The Spirotherm Dirt Separator is a nice item but pricier than a good wye strainer. I would use an iron strainer, bronze has always been up there.

Mad Dog_2

The Flat plate is great ....AS LONG AS

someone is flsuhing it down a couple of times a year - they won't! Steam condensate will form carbuncles inside the indirect, if they don't stay on top of maintenence it will clog up in short order. But in any case, as the boys said, a very good strainer. The equivalent sized Flat plate will not be cheap either. That $800.00 price sounds a little high. John, I have pulled ALOT of hot water and radiant zones off of steam boilers. I can always get them to work be they can be problematic and noisy. By The time you are all said and done piping them up, you have 95% of a boiler install. Have you considered a tankless water heater? Last, you still don't have a completely separate heat source. I know...you are trying to keep cost down for them, but I often find that WE wind up with all the headaches. Also, perhaps a Brad White Combicor is an option? I still use any one of these strategies, but when I can get them to go for a little more $$$, a seperate heat source is the best way in my opinion. Mad Dog

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DanHolohan

It's not the weight of the water closing the valves,

it's the limit of the height, based on atmospheric pressure. The air pressure is actually keeping the water in the loop on these open-system jobs. In NYC, your limit is 34 feet straight up.