Indirect heaters

Wayco Wayne

I was talking to a sales rep and he told me there was a big difference between horizontal indirects and vertical indirects. I didn't know this and usually use the horizontal when I can to save space on the footprint of the boiler and indirect heater, for example a Buderus with the tank on top. He said the horizontal makes for slower recovery. What say you all.

Unknown

Maybe he was talking about

The HL Phase 3 indirect ? Normally , they stand up , but you also have the option of laying them down - they come with 2 brackets for this . I think they lose about 30% of their output when you lay them down .

Alan(CaliforniaRadiant)Forbes

If the surface area

of the HX is the same, why would the recovery change?

Maybe when you lay them horizontally they go into sleep mode.

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Unknown

I think it has to do with

the positioning of the inlet and outlet of the domestic pipes. When you lay the tank down , both tappings are in the middle , and some of the hot water is basically trapped in the tank . I think you also have to replace the dip tube with a special bendable one. Or it could be going into sleep mode . Im gonna see if I have the instructions and check it out.

Paul Pollets

Myths

Horiz indirects actually have a slightly higher recovery. The water stratifies in vertical tanks and would be slightly cooler at the bottom of the tank. The horizontal tanks rarely exceed 24" in height. Recovery rates have more to do with input and pump flow than height. What manufacturer makes a horizontal tank with lower recovery rates than a vertical? Recovery rates are usally specified.

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heatboy

Would you agree..........

that recovery is a function of boiler output, pumping and pipe sizing more than anything else?

The only horizontal tanks I have used are Viessmann's and I believe gallon per gallon, the horizontal tank does better. I know that you can draw more than 90% of the tanks capacity before it starts to go cold, with no re-heating that is. So a 53 gallon horizontal has 50 gallons of hot water available. The 53 gallon vertical will draw about 70% before it starts to go cold, which means there will be 37 gallons available. They both will give 160 GPH continously with a Delta T of 100° (40° to 140°) if piped and pumped correctly. I'm not sure about other manufacturers like Buderus, etc. ME or Cheese could probably compare the Buderus tanks since they use quite a few of them.

hb



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hr

I agree with Ron Jr.

I have a Phase 3 indirect mounted horizontaly under my Weil GV. There is a slight derate factor included in the manual when mounting them horizontal. They supply a special dip tube for horizontal, mounting which helps. The HX area doesn't change, just the ability to squeeze all the hw out.

Perhaps if the the tank was designed specfically for horizontal mount ( cold in at the very bottom and hot out at top dead center) the output would be the same or better. I believe the H & C tapping locations hold the key.

hot rod



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ScottMP

Buderus Indirects

There definatly is a difference between Horizontal and Vertical tanks. I wish I had the reason.

Buderus rates their tanks differently.

32 gallon vertical -- 155 gal/hr with a 116,000 BTU/HR

36 gallon horizontal- 97 gal/hr with a 73,000 BTU/HR

They may be rated lower for horizontal since the smaller boilers sit on top and they are showing what those boilers will do. I suppose you would need a curve to extend the output to the same input ratings. ONE of you out there must know how to do this.

The 79 gallon model is also rated differently. Again higher recovery with higher input. Are they the same at the same input ????

Scott

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Wayco Wayne

I was thinking

perhaps its because the spiral of the loops cut through the statification of the potable water because the loop is sideways instead of the HX being at the bottom where the coolest water is making the delta larger and thus more heat being exchanged faster. Just a thought.

heatboy

It would.........

certainly be closer if the boiler outputs were the same. Boiler output mean nothing if the indirect is not piped or pumped correctly. If you have a 125K BTUH boiler, but you only pipe the HX of the indirect in 3/4" (I have seen this time after time) how can you expect to utilize all 125K for recovery? You can't. Pressure drop and GPM through the HX is always the biggest variable, right? I know the difference between Viessmann's and Crown/Burnham's HXs in their indirects are huge. The pump you can use on Viessmann's indirect may (probably) not work on Crown's indirect due to the steep pressure drop through the HX. Lots of variables!

hb

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ScottMP

Typing before thinking

I think the difference is the size of the heat exchanger. The Horizontal heat exchanger can not be as long due to sagging in the tank ie;support.

The horizontal HX cannot accept as much input as the vertical can

Scott

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kf_2

Phase III in horizontal application.

When the Phase III is used in a horizontal application the performance is reduced by 25% because of 2 reasons:

1) The boiler supply tapping, which is normally at the bottom of the tank-in-tank heat exchanger in the vertical position, now enters the top of the tank and the cool return water is pulled from the bottom of the tank.

2) The normal dip-tube is replaced by the horizontal dip-tube that is perforated along the entire length of the bottom of the tank. So in this application the cool inlet water makes up a much larger percentage of the tank capacity.

The Viessmann horizontal tanks are manufactured specifically for horizontal applications. The coil type HX runs almost the entire length of the BOTTOM of the tank bringing the hot boiler supply directly into the bottom of the tank where it is needed.

kf