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[Crossir]

Well I screwed up big time! I purchased the Rehau 32mm pipe under the assumption that it was 1.26 ID. I was getting info both ways that it was only about an inch ID or that it was 1.26 ID. Well we all know what happens when you assume! I decided to take a gamble and lost. Anyway, I have 240' of 32mm (about 1 inch ID) for sale at a good price in central New York if anyone is in the market.

[slimjim]

What do you have for a heat load, you should be able to deliver about 200,000 BTUs with that pipe by doubling up the circs if you need to and paying attention to resistance inside the building.

[Crossir]

It was figured that I have roughly 130,000 btuh of fin tube in the house. So I would need that plus our domestic hot water. My plan was to run 1.25 underground and inside the basement to the hx. Then I was going to use mono flows for a smaller hx to heat the  Dhw. Total run, 240' outside and another 45' in the basement to the oil furnace. Also I would want to figure any loss for the wye strainers. Thanks for any advice.

[slimjim]

Honestly, I would love to sell you some pipe BUT, with what you have you will be fine!

[RSI]

You would need to get 1-1/2" pex to be much larger. Your pipe is about 1.032" ID and 1-1/4" pex is 1.054" ID.

How many GPM are you trying to get to the house? If you had just the pipe mentioned in the loop, a Grundfos 26-99 would move around 9 GPM and a 15-58 would be over 6 GPM.

If you went up to 40mm pex, you would get about 15 GPM with a 26-99 and about 10 GPM with a 15-58

1-1/2" pex would be about 14 gpm with 26-99 and about 9 with a 15-58.

[Crossir]

If I am reading the flow charts right, and I may not be so please correct me if needed.
1 gpm= 10000 btuh
With a 20 degree  temp drop I should be in the neighborhood of needing 150000 btuh.
With 130000 btuh of fin tube and DHW I should need at least 15 gpm.

[RSI]

Your btu's per gpm are correct. If you can make it work with 30 degree drop, the pipe would be fine.

[slimjim]

The chances of all your heat zones calling for heat at the same time are very slim and those times will be brief, I had originally thought you were talking about a 240 foot run in one direction, I now see that it's total, RSI is right, you will be fine with a single 26-99 as long as you don't use a lot of short 90's.

[oldchenowth]

For what it is worth Crossir, I am running a metric line from the burner to the house that is about the 1.03" ID and 1" pex from Menards that I figure is 7/8" -15/16" at best. I ran to my HX in the furnace first then 10' to the 40 plate DHW HX back to the metric return line.  Never once starved for heat in the forced air or DHW.  Wife likes it at least 75 in the house all winter and 2 girls in the house that could make the hot springs ice over all at the same time.  My humble opinion is it will work just fine for you.  If it is already installed, I would test it out his year and see what it delivers.  These guys know ALL the technical, I just know what I can afford to fix or replace

[Crossir]

Thanks for all the feedback. Here is the current situation. Slim, I miss spoke (typed), the 240' plus the 45' inside is a one way distance. My house is an old 1850's 3800 sq. ft. Farm house with some miner updates done in the 40's then some other updates done in the 70's. I would like to make sure that there is enough GPMs to add on some extra load, especially the basement where the old inside wood boiler put off lots of radiant heat to satisfy that space. The 32mm is not installed yet. When I called today and asked the supplier of the 32mm what the inside ID is, they again told me that it was 1.26. They would sell it again to some other poor, uninformed sap! After informing them that I just purchased 240' of thier  so called 1.26 ID pex, they offered me  $300 to pay for a bigger pump. So it's not a done deal yet, hopefully they will work with me and offer a refund of some sort. What would be the price of a pump to meet this demand on a 1" line? With it not being pressurized, would it cause any premature pump failure due to cavatiation or anything else of that nature.

[RSI]

If you go the big pump route, I would use 2 in series and only run the 2nd when needed.

You will only be able to gain a couple GPM with a large pump(s)

If they told you it was 1.26" ID, maybe they sent the wrong pipe. I would have to look up the specs but 40mm might be close to that.  What you got is 26mm ID and 32mm OD.

[slimjim]

Good point RSI, check your receipt and see what they billed you for, I don't think it will be necessary but perhaps they will exchange it for the larger pipe, if you don't mind me asking in the open here, how much per foot did you pay for it?

[Crossir]

 Well the distributer made right on the miscommunication/misinformation deal on the 32mm. They are going to refund 100% cost plus the shipping charges. Thanks for all the help in trying to make this situation work. The 32mm may have been enough but I wasnt comfortable putting all that time and money in the ground and it be just short. Anyways, I thank the distributor again for making right and you all for the help. I will be posting here when the next problem arises and I need professional advice.

[slimjim]

WOW! That is awesome, most dealers/distributors won't do that, how about giving them a shout out!

[juddspaintballs]

 

Now for the correct pipe