Best Of
Re: Long-term project to update old hydronic -- let's start with the Mercoid switch!
The precharge on the expansion tank has to be set with no pressure in the system. If it is at 16 psig with 30 psig in the system then the bladder is expanded as far as it can go, the tank is waterlogged likely because of insufficient precharge.
If it keeps dribbling and replacing water that fresh water will quickly corrode everything in the system, especially the boiler.
mattmia2
Re: Help with boiler
Have a bicycle pump ready to add more air to the expansion than just in case you have lower that 12 PSI air pressure in the empty tank.
- Turn off the valve that feeds the pressure reducing valve.
- Then open a boiler drain or purge valve to let out some water until the water pressure in the boiler goes below 5 PSI on the gauge.
- Now take a pressure test of the air side of the tank with the tire gauge.
- if the air pressure is below 12 PSI then add air pressure with the tire pump.
Re: Help with boiler
Sorry I was being distracted
You are correct.
If you have more that 15 PSI then you want ot lower the pressure to between 12 and 15 PSI
Re: Help with boiler
Since you do not have water coming from the air side of the tank, you are probably in good shape. but the 20 PSI in the tank is not the "empty" air pressure. that is the boiler water pressure compressing the air in the tank. In order to set the tank pressure properly you can have no water in the tank.
This comment explains how the boiler pressure effects the tank pressure and why you need to measure the tank pressure with the water side at "zero" 0 PSI
Re: Long-term project to update old hydronic -- let's start with the Mercoid switch!
you might do a drain down come spring and get an actual volume if water in the system. That is the best way to size an expansion tank
If you improve the envelop that much, Id guess that boiler will be grossly over-sized
A mod con would work great in a home where the radiation may be greatly oversized after the improvements
hot_rod
Re: using a boiler in my shop. can I use PEX?
PureFlow is a Pex-B, per Viega. They have many studies and videos out there comparing their products to cold expansion/ Pex-A and it's quite apparent that they will not allow cold expansion with their tubing. I've personally run across a few instances in the field as well as ran a few tests myself using cold expansion with Pex-B and C with no apparent trouble, but I'd imagine under certain circumstances it'd fail prematurely. The Sioux Chief in particular, being orange in color, when expanded turns white which looks very sketchy but it seems to hold just fine. I did the same with a chunk of cheap BlueFin tubing and it also turned nearly white, but the sidewall of the tubing blew out before the expansion joint did… Technicalities, I suppose, but the point was that Viega does not approve expansion fittings for their tubing.
GroundUp
Re: Burnham 2 started gurgling and water rushing sounds
You’ve got no pressure on the boiler. It should be a minimum of 12 psi cold for a one story house - 18 psi cold for a three story house.
You may have a bad fill valve, but even if that’s true, it won’t lose pressure unless there’s a leak(s) on the system.
Ironman
Re: Radiant floor heating plan help
2" foam, closed cell like Owens Pink or Dow BlueBoard.
The edge insulation is a big deal, and if it is a slab on grade that is a tricky detail to cover the top edge. Usually a metal Z flashing under the siding to cover the top edge of the foam. Then edge foam should go down to frost level. May be a detail in that guide.
Yes to mini splits for AC or shoulder season heat.
Take pics of the tube layout for future reference. A drone is great for that.
Good for you for getting opinions before you start. So many bad installs come by here that could have easily been prevented.
hot_rod
Re: What type of circuit breaker is this?
looks like it is probably a commercial main lug subpanel and the overcurrent protection is on the feeders at the switchgear.
mattmia2