Central Boiler thermostatic valve pipe size question?

LegendsCreekFarm · July 02, 2016, 09:23:56 AM

The thermostatic valve that came with my central boiler I believe is 3/4. My thermopex is 1", so I will be connecting the thermopex to the thermostatic valve by reducing down do 3/4, however, when I come out the other size of the valve and plumb over to the heat exchanger should I bring the pipe size back up to 1" as I am using a 1" size heat exchanger?

I don't know why they sent a 3/4 thermostatic valve when the standard is 1" pex and above. Not sure how to plumb this up.

r.man · July 02, 2016, 09:41:45 AM

I would check with the supplier to make sure they meant to send the 3/4 and if they did ask them how it would normally be plumbed, no sense re inventing the wheel. Other than that I would do it the easiest way, with the restriction already there I don't think it will make much difference.

LegendsCreekFarm · July 02, 2016, 03:53:29 PM

I plan to contact the supplier, however, I looked online and I can only see these valves available in 3/4, so I am wondering what everyone else did with theirs to get to 1" after the valve.

Gearbox · July 03, 2016, 09:37:35 PM

look at the opening of a 3/4 valve and a 1 inch pex fitting I think they are the same opening size .

coxy · July 04, 2016, 06:19:12 AM

don't know never looked to close but some say 1in pex is the same size as 3/4 standard pipe :-\

Roger2561 · July 04, 2016, 06:40:43 AM

I have a CB E-Classic 1400 and I have the 1" thermopex pipe. If you measure the ID of it, it is very close to 3/4" not 1", thus the reason for the 3/4" thermostatic valve. Roger

LegendsCreekFarm · July 04, 2016, 02:09:26 PM

Well that makes a lot more sense. I am going to be using black pipe for everything from the thermostatic valve, to the line that runs to the boiler so I will need 1" black pipe fittings, but will need 3/4" x 1" couplings to get me there. Thanks for the help! I am sure I will have 500 other questions as I get through this install over the next week.

Gearbox · July 04, 2016, 04:26:43 PM

I used brass in mine . The factory said use no steel with a stainless boiler . Pex brass fittings are cheap . you are putting 10,000 dollars into a boiler why go cheap on a $ 100 worth of fittings . I also used the stainless pinch clamps . The copper clamp rings will leak if side loaded .

LegendsCreekFarm · July 04, 2016, 06:08:36 PM

Can you explain why they say that? I wasn't told the same info about using steel pipe with this boiler?

My neighbor used black pipe and his boiler is at least 10 years old. Just want to make sure I do it right.

Holmes · July 04, 2016, 07:48:59 PM

The non pressure boiler is open to the air , the water in the boiler absorbs oxygen, the oxygen makes the steel piping rust. I would use 1" pex. two, 3/4" pipes are mixing water to the outlet so for flow reasons it may help to have the 1" pex.