1 1/4 thermopex cut to length?

[hartkem]

I need a 160' of 1 1/4 thermopex for my EKO 40 boiler. There are several central boiler dealers around the northern part of kansas city, missouri and none of them are willing to cut a roll. They act like no one ever uses it and im crazy. I have 500 gallons of remote starage which is why I think 1 1/4 might be a good idea. Im not opposed to using the 1 inch stuff but don't want to regret a bad decision. I thought about foam in trench but would prefer to stick with a quality premanufactured product. Im heating a 3000 sqft modern house. I have a 011 Taco pump for the primary loop to the storage tank 160' away. I need to make a purchase in the next week or so.

Thanks

 

[Bob Rohr]

I need a 160' of 1 1/4 thermopex for my EKO 40 boiler. There are several central boiler dealers around the northern part of kansas city, missouri and none of them are willing to cut a roll. They act like no one ever uses it and im crazy. I have 500 gallons of remote starage which is why I think 1 1/4 might be a good idea. Im not opposed to using the 1 inch stuff but don't want to regret a bad decision. I thought about foam in trench but would prefer to stick with a quality premanufactured product. Im heating a 3000 sqft modern house. I have a 011 Taco pump for the primary loop to the storage tank 160' away. I need to make a purchase in the next week or so.

Thanks

Remember the id inside diameter of 1-1/4" pex is 1". So the same as 1" copper. 1-1/2" PEX is 1-1/4" id. Sold in 100 foot coils. I know a supplier in KC that has two 100 foot rolls of 1-1/2" pex if you need.

 

[goosegunner]

I have a name of a guy in WIsconsin that I bought my Logstor from. The 1" logstor has an inside id of just over 1". I am pretty sure it is about the same as 1 1/4" Thermopex but you would have to verify.

pm me if you want the info. Shipping might be high but for you. He cut to what I wanted and shipped it on a pallet.

gg

 

[hartkem]

Goosegunner,

Im sure your correct the 1 1/4 thermopex is around 1" ID. Im trying to decide if I should pursue the thermopex or logstor or go the foam in trench route with 1" pex al pex which also has 1" ID.

 

[greg in MN]

Remember the id inside diameter of 1-1/4" pex is 1". So the same as 1" copper. 1-1/2" PEX is 1-1/4" id. Sold in 100 foot coils. I know a supplier in KC that has two 100 foot rolls of 1-1/2" pex if you need.

I installed 1 1/4 central boiler thermopex with my Econoburn and as I recall it is 1 1/4 inside measurement. Maybe someone has a piece laying around and can measure it.

 

[katman]

I put in about 90 feet of 1 1/4 thermopex and connected to 1 1/4 copper after transition from underground. It is a great product. I can't recall inside diameter but I think it is larger than 1 inch. Make sure you get the compression fittings Central sells to make you transition foolproof. I paid $18/foot for the thermopex. In my area it would have cost about the same for foam in ditch. The lowest price contractor wanted $12/foot for foam and the high bid was $28/ft. Add in the cost of pex and the thermopex was an easy decision. Give yourself a little extra if you have any bends and pick a warm day to lay out the thermopex. I did mine during the winter and getting the coil memory out required a lot of sunshine.

 

[Bob Rohr]

The Central products list the tube as CTS which means copper tube size. The outside diameter is the same as copper tube.

So 1-1/4" copper tube has a outside of 1-3/8" ID varys based on wall thickness with copoper Type L m or K, K being the heavy wall.

So if 1-1/4" pex is CTS 1-3/8 od then the inside would be the wall thickness less. If the wall is 1/8" that would provide about a 1-1/8" id. So a bit larger than 1" copper id, but smaller than 1-1/4" copper id.

The tube supplier should be able to supply a pressure drop chart or multiplier for their tube. Then you could determine the pressure drop with various GPM flow rates.

My HDS program show 1-1/4" pex with a suggested 11 gpm flow of 180F at 3.9 fps. 1-1/2" pex 15 gpm flow 180F 4.1 fps 4.1 feet of head per 100 feet of tube.

To move 150,000 BTU/hr at a 20 degree ∆T would require 15.5 GPM 1-1/2" pex.

Undersizing the pipe will cause installers to up the size of the pump to try and over come the flow restriction. increasing the pump increases the cost, operating power, and leads to excessive velocity. It can also shorten the life of the circ, especially on open systems that do not provide enough pressure to prevent cavitation.

hr

 

[salecker]

Go with the foam in trench.
might cost a couple bucks more but it can't be beat.