3/4 \"piping to Munchkin

Ron Schroeder

> The gas pipe sizing is required due to the burner <BR>
> modulation: The larger sized pipe allows a bank <BR>
> of fuel to allow the gas flow changes in the <BR>
> event that the regulator can not react quickly <BR>
> enough. <BR>
<BR>

kevin coppinger_4

I had a propane supplier....

hook up a T50 munchkin for the HO at a job I was doing a heat conversion. I asked for 3/4" pipe (as HTP requires) to the boiler and when I came back to fire it up they had done 1/2" tracpipe....it is only a 25' run and that will carry plenty of btu...but I was under the impression that it was more for pressure purposes w/ the gas valve that 3/4 is the norm...am I wrong to insist on the 3/4"? kpc

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Rely_2

gas pipe

what is the total run of gas pipe from the step down regular to the boiler? propane operates at 10-13" WC vers natural gas 4.5-7" WC

kevin coppinger_4

from the bottle...

where the reg. is is maybe 25'...kpc

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Steve_35

I called HTP and asked about that

They told me the reason they require 3/4" is because too many people either don't know how to size pipe or don't care.

IOW, size the pipe correctly and all's well.

Guy_6

piping

The gas pipe sizing is required due to the burner modulation: The larger sized pipe allows a bank of fuel to allow the gas flow changes in the event that the regulator can not react quickly enough.

Steve_35

Not according to the tech folks at HTP.

And think about that for a second. If they were counting on a "bank of fuel" they'd require larger pipe when you had shorter runs to maintain that bank.

They're trying to address to poor isntallation practices of some contractors. Pretty funny when you think those same contractors are doing the piping and design for the boiler as well which is at least as critical as proper gas pipe sizing.

kevin coppinger_4

if that's the....

case...why don't they just put in a 3/4" gas cock at the gas valve? kpc

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Steve_35

Beats the heck out of me.

Maybe because they're $0.50 more?

Ron Schroeder

Kevin

Pitman is correct on all accounts, but on the other hand you should get what you ask for. And yes if you figure in the savings on using 1/2" gasvalve and that nipple to the gas control times the nuber of units built you know why they use that size.

jwade55_3

Here is what I know.

And it isn't much, but I've been called in on several jobs, where there had been nuisance boiler faults, typically F9/F10 codes. After looking over everything, taking all readings, etc the only thing left was the CSST 1/2" gas line. Had it changed to 3/4", and in these cases, the problems went away, knock knock

J

kevin coppinger_4

THAT is what....

I am concerned about....nothing like a new install to go bad and the customer lose confidence in you....ty,kpc

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Guy_6

Past

I WAS a tech guy at HTP, and the explanation that I gave was what I had been told by the engineers that designed the boiler, which actually IS what you are saying- 1/2 inch MAY work if done properly, and all the fittings/regulator/etc. are condusive (sp?) to flow.
The 3/4 inch will work regardless. As stated above- who wants to face an irate customer only to tell them that the boiler is acting up because it was not installed per the manufacturer's guidelines.

Ted_9

Hey Guy, can you tell us if you are still in this field and which company or brand. I just though it would be useful.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Steve_35

So you can run 200' of 3/4\" on natural and all is well?

My point was and is that proper sizing is required. By requiring 3/4" gas line HTP is trying to reduce the number of jobs where improperly sized gas piping is an issue.

My question to the HTP tech I spoke with was is 3/4" REALLY required to have proper function of the Munchkin. His paraphrased reply was, "No, the pipe needs to be sized properly and most of the problem installs aren't."

In fact I look at HTP natural gas sheets and they are less stringent than the design sheets I have from the local utility. In addition, HTP's sheets make no reference to adding to the TEL for fittings.

The bottom line is the 3/4" sizing is an effort on HTP's part to reduce the number of problem installation due to poor gas piping design. There are many instances where 3/4" will be undersized particularly with gas.

But back to the OP's question of is the 1/2" sufficient. You mention it's a 25' run of propane. If the Munchkin is the only thing on the line and the TracPipe is connected directly to the regulator and directly to the drip leg tee at the Munchkin regulator and the length is no more than 25' you're only drawing gas at about 55% of max capacity. Check the pressure when the unit is running. That's the main criteria in the final analysis. Can the piping deliver the required flow at the required pressure.

radmix

gas pipe

I just installed a munchkin m 80 last weak. I told the gas company to install 3/4 inch pipe but the installer insisted that 1/2 inch pipe on a two stage regulater with a 25 foot run would work.as soon as I turned the boiler on f09 fault. I called htp they said if there is more then a 1 inch drop in water column the boiler will go into fault. I called the gas company back only to recieve a very bad attitude. the installer said that he knows propain he has been doing this for 20 years and htp does not know what there talking about.But when he changed the line over the boiler fired off with no problems. HTP also told me that the inside diameter of the flex gas pipe is smaller then the black pipe.

Brad White_40

Of Flex Gas Pipe and Attitude

You are spot-on about restriction in flexible gas connectors compared to hard pipe of the same diameter.

Ever blow into one? Ghostly! (Do NOT ask how that came about, for the sake of decency, please...)

What your posting also illustrates is how some folks, like your gas company technician, are so impressed with what they think they know that they will resist all facts and evidence to the contrary. Wonder how we evolved as a species? Pure dumb luck I suppose.

Ron Schroeder

radmix

1/2CSST is rated for either 82k or 94k at 25 feet to close for a T80 but you have 30k leeway on a T50 therein lies the diference. But as I said before Ken should as you sould be given what you specify noy what they choose to give you.