Redoing my boiler setup. Wondering if I should swap the zone side...

rsilvers

I am sure I don’t need two loops. I just wanted it. But that is an interesting idea with the mixing valve. My hot water loop on the system I am taking out had that. I am very open to that. 

Pex to me looks modern. I assume young home buyers see copper and think it’s an old system. I really wish my walls had Pex because of the burst resistance, though I know nothing in this room will freeze. 

Zman

PEX will not handle the heat as well if you have a boiler malfunction.

NoelAnderson

The Cross motor will not work in that position. It needs to be rotated 180 degrees so the Cross name is facing upright. (See the picture in my post above.) It would also be a good idea to use a magnetic dirt separator when using the Alpha II pump.

rsilvers

Yeah but I just flip it later when I configure it, right?

rsilvers

The well water is extremely iron rich (stains white clothes brown), so perhaps a MDS is a good idea.

NoelAnderson

If your cord is long enough to reach the controller. The MDS is for rust produced by other components in your system, Iron boiler, pipe, radiators, pumps, and tanks.

rsilvers

The controller can be moved as it isn't wired yet. I ordered the MDS.

rsilvers

Zman said:

PEX will not handle the heat as well if you have a boiler malfunction.

This is a vacation house that is changing to heat-pump as primary heat, and oil as backup.

Uponor hePex doesn't actually burst even at 210 degrees F at 150 psi after 720 hours - 10x the max pressure it will ever see. The actual pressure that it will burst at 200F is 240 psi - 20x the pressure it will be run at.

https://www.uponor.com/getmedia/1dda1b8c-5963-4d81-8f32-d8a3ba4f38bf/hydronic-piping-product-guide.pdf?sitename=USA

I will call Uponor Tech services and see if anyone does this. Searching around, it seems like no one does in the US. Maybe in Germany? I don't know.

rsilvers

The Cross Manifold has a circulator controller. I can connect that to the secondary circulator pump. 

Do I also have the primary circulator turn on from the same wire, or do I leave that on the HydroLevel Outdoor Reset Aquastat?

DJD775

I don't see in the instructions where the pump is connected to controller. I doubt that if there is a terminal to power a circulator it is rated for multiple circulators.

rsilvers

There is no AC terminal on the Cross. There is 24v circulator out terminals and you connect their optional relay that uses that to switch AC power. 

A friend who owns an HVAC and oil fuel company says that I should connect the secondary pump to the Cross controller and the primary pump to the HydroLevel Outdoor Reset Aquastat. That sounds likely correct. 

rsilvers

Is a copper press connection (on both sides of the fitting) a valid way to connect copper to Pex? Or must it be a copper press or sweat on one side and expansion on the other? I searched and can’t find anyone using copper press itself onto Pex.

rsilvers

Trying to simply the layout.

DJD775

rsilvers said:

There is no AC terminal on the Cross. There is 24v circulator out terminals and you connect their optional relay that uses that to switch AC power. 

A friend who owns an HVAC and oil fuel company says that I should connect the secondary pump to the Cross controller and the primary pump to the HydroLevel Outdoor Reset Aquastat. That sounds likely correct. 

That should work.

rsilvers

I called Uponor Technical services. He said the "design temp" (what you can design around) for HePex is 200F degrees at 80psi for continuous 25 year service. They warranty it for that. The way it is certified for this design temp is that it needs to be able to withstand 3x the design pressure - so 240psi at 200F. That is the actual burst pressure. In fact, that is how they came up with the 80 psi rating - they found the burst pressure to be 240psi, and divided by 3 - and that became the design limit. He said in Europe, it's like 80 percent Pex and 20 percent copper, and in the US it's the opposite - most people use copper for near boiler. He thinks the reason why is that it is rigid, and pipe-fitters like that for fixturing. I am sure tradition plays a role.

rsilvers

Made some progress. 

rsilvers

It is operational. Before and after:

DJD775

You cleared up a lot of space around the boiler! Everything working as expected?

rsilvers

When I first fired it up, it was nice to see the air bubbles through the pipe to help bleed it. The flow meters were great because I could see that one zone was not flowing and I needed to try harder to purge it. I succeeded. After it got up to temp, three threaded connections that I had sealed only with MegaLoc started to leak. I shut down, added Teflon tape and more MegaLoc, and it has been fine since. I suspect that the fact that MegaLoc is easy to clean means that it is somewhat water soluble. I was sure I used a lot of it and got it into the root of the threads the first time. I ignored the advice of people who said they use Teflon tape along with the thread sealant because I decided to trust the instructions on the can.

A knowledgeable friend said he uses https://www.henkel-adhesives.com/us/en/product/thread-sealants/loctite_55.html

rsilvers

Currently I have no check valves in the pumps. I think I should add one to the secondary pump but keep none on the primary pump. My reason for none on the primary is that there would be no way to dump the pressure to the left of that pump if I wanted to service the line, unless I made the left-side flange one with a purge on it or added a separate one.

SuperTech

Is that 3/4" PEX for the supply and return from the boiler? The tappings on the boiler are 1 1/4", do you really think it was a good idea to restrict it down that much? It looks like you ignored a lot of good advice besides the recommendation of using Teflon tape.

rsilvers

It’s 1 inch HePex, which is good for about 100,000 BTU at a 20 degree drop, and the new boiler is going to be 85,000 BTU.