OWB Pipe 1" or 1 1/2" ??

[pipe76]

Recently took delivery of a central boiler 6048, the run from the house is about 120 ft. My plumber insists on the 1 1/2", while most everyone else uses 1 in." Any thoughts?

 

[Husky137]

I've got 1" on mine without any problems, as recommended by CB. Has your plumber done an install of one of these before?

 

[Marklambert61]

pipe size

1" pipe will carry more than enough water needed...

With standard type pump you good to about 300ft.


Mark...

 

[HardyOWB]

Mine is 150ft from the house. One inch pipe = no problem.

 

[tanker]

your heat exchangers,either plate type or sidearm are 1",no need to go the extra expense of 1 1/2",won't do the job any faster or better

 

[bassman]

1 inch is the norm but how much to go to 1 1/2 ???
just make sure it is insulated well.

 

[hink]

the rule of thumb in the heating industry is to move 1gal. per min for every 10,000 btu's you are trying to produce. This is for a conventional hot water system opetating at 180 degrees. Other factors would be heat exchanger efficiencey and if it is feeding a warm air coil. If you were to stay with 1" you could more than likely change the pump to one that will move more water( if you needed to). I've never dealt with an owb so I'm not sure what a standard pump would be. You can probably access pump data on a pump manufacturer's web sight.

 

[pipe76]

Pipe question

Hi all , thanks for the replys. My plumber was telling me the calculations didn't work with the 1 " and that by useing a 1 1/2" it was better, something about the pump not having to work as hard, not sure. I bought pipe in bulk because two of my friends are putting them in aswell, so the pipe wasn't too much more expensive.

 

[Sawmill]

The pipe may not have cost much more but wait until you start buying fittings. I know where there is a couple of OWB's that are farther from the house than yours and they only are using 3/4 inch. They are in an area that get below 0 on many nights and have no problem. How are you going to insulate the 1 1/2 inch.

 

[pipe76]

the pipe is from http://www.pinnaclesupply.com/tsp_2.html, not as good as thermo pex, but should do a good job. I hear you on the fittings, bigger pipe, bigger fittings. I guess all in all hopefully it wont be bad for the system.

 

[HUSKYMAN]

Its not just bigger fittings, you have to snake everything down to 1" for your exchangers, fittings on your boiler, etc. By going to 1.5" you have about $100 in extra fittings I am guessing, along with the potential to have a lot more leakage

 

[Crofter]

With no insulation between feed and return lines you will have more temperature drop from boiler to heat exchanger with the larger dia. lines than you would with the smaller. Some loss of efficiency.

 

[tanker]

well his plumber is gonna have a sh!! fit when he can't speed it all up going through 1" fittings glad I'm not a profesional Iwould have had to argue with Central Boiler on this if I had known any better.My run is 155' and running a Taco9 pump

 

[bassman]

fittings bigger than 3/4 are very pricey and can be 4 times as much but you have the pipe so whatever iys done.
now lets look into insulation .
what are you planning on doing ??

 

[windthrown]

Recently took delivery of a central boiler 6048, the run from the house is about 120 ft. My plumber insists on the 1 1/2", while most everyone else uses 1 in." Any thoughts?

Sounds like he is making money off the piping and fittings. 1" PEX inside diameter is about the same as 3/4" copper. Most all heat exchangers are 3/4" or 1" fittings as well. As other have said, 1" PEX is fine. That is what I plumbed ours here with, and what the majority of OWBs are plumbed with.

 

[windthrown]

Hi all , thanks for the replys. My plumber was telling me the calculations didn't work with the 1 " and that by useing a 1 1/2" it was better, something about the pump not having to work as hard, not sure. I bought pipe in bulk because two of my friends are putting them in aswell, so the pipe wasn't too much more expensive.

Now, there is a line of bull, the pump not having to wark as hard with a larger diameter PEX line. I would look for another plumber if I were you. In actuality, you want to locate the pump at the lowest point in the line, as in an open system there is low pressure and your pump will fail (in time) mainly from cavitation (bubbles forming on the impeller). Adding a little pressure by putting the pump low or increasing the line back pressure will acturally help to avoid typical Taco pump failure. *shrug*

 

[oneoldbanjo]

The interior volume of 1.5" pipe is more than double the interior volume of 1" pipe, and this will cut the velocity of the water in half (velocity - not flow). A 1" circle has 0.79 square inches, while a 1.5" circle has 1.77 square inches of area. The benefit of this is that fluid flow through pipe experiences friction loss - and the larger the pipe the slower the velocity of the fluid the less friction loss that will occur and the higher the flow will be. You can reduce the pipe size to 1" when you get inside and will still benefit from the larger 1.5" pipe between the OWB and house. I don't know if it is necessary - but it won't hurt a thing to do this.

My OWB is about 130 feet from my house and uses 1" and works fine.

 

[HUSKYMAN]

The interior volume of 1.5" pipe is more than double the interior volume of 1" pipe, and this will cut the velocity of the water in half (velocity - not flow). A 1" circle has 0.79 square inches, while a 1.5" circle has 1.77 square inches of area. The benefit of this is that fluid flow through pipe experiences friction loss - and the larger the pipe the slower the velocity of the fluid the less friction loss that will occur and the higher the flow will be. You can reduce the pipe size to 1" when you get inside and will still benefit from the larger 1.5" pipe between the OWB and house. I don't know if it is necessary - but it won't hurt a thing to do this.

.

It will only hurt his wallet, to the tune of a couple hundred bucks, and there will be more than twice as many places for leaks to occur

 

[oneoldbanjo]

It may hurt is wallet some to increase to a 1.5" pipe, and I would only use the larger pipe if necessary. Using 1.5" pipe will significantly reduce the head loss in the pipe as the calculations for friction loss uses the "Velocity of the fluid squared" - so increasing to 1.5" pipe will cut the friction losses into 1/4 the loss that occurs in a 1" pipe. I don't know if that will get the pump into a cavition condition - somebody that knows more about these little pumps will have to let us know what the operating parameters are for these pumps. In my own installation the Woodmaster dealer used 1" PEX and my OWB is about 120 feet from my house. He supplied the design of my system to Woodmaster and they confirmed the installation would work - and in the 5 months that it has been in service it works fine.

I don't see why the number of fittings would double. The OWB only needs to have one fitting in each of the supply and return line that increases the 1" pipe fitting on OWB to 1.5" diameter - and the same needs to happen in the house in the return line as the 1" to be used with all the heat exchangers will need to be increased to 1.5" to connect to the PEX. At the furnace you would be adding a pair of 1"/1.5" brass or stainless couplings and at the house you probably would use a pair of 1"/1.5" PEX couplers.