Two Questions on a New Radiant/Infloor Install

OUBrew

I had an in floor system installed when I built my home 12 years ago. I went cheap and it cost me. Several issues but we eventually made it work. It was an open system and was run off a 130K Polaris. It always bothered me so this fall I decided to clean it up. I got several estimates and made the decision to do the majority of work myself. I drew up the schematic with the Boiler tech advisor and went to school on hydronics. I have a whole new respect for the really good professionals out there. I piped the new system Primary/Secondary at 1". I have 3 new zones...one 8' baseboard run and two wall hung vertical radiators. Those are run off the top manifold. I want to run those at 170-180deg. After the mixing valve I have the old/original manifold run to the in floor system. Water temp set from the mixing valve to 120deg.

I ran the new radiant zones to a Taco 3 zone relay. I have one bedroom in floor run to a single zone relay and the other two in floor runs connected to 2 Goldline SP-30 Set Point Controls. I have connected both zone relays to the TT connection on the boiler. I hired a local heating/plumbing company to come out and run the 3/4" gas line to the new boiler and perform a combustion analysis. I also requested they fill the system zone by zone and purge all of the air. He was on-site for 8 hours yesterday and called me when he left. He was a very cordial professional and was not condescending about my work...even though he had some concerns and questions. Not the way their company designs pipe run/systems etc. He said the system was up and running and putting out heat. My wife said radiator in master bath was warming up.

I got home and hour later and went down to check his work and see the boiler in action. I noticed something wrong immediately. Pumps were overheating and sounded like they were running dry. 2 radiant zones and the basement in floor. Pumps too hot to the touch and supply piping cold on push side of the pump/warm on suction side. Pressure on Secondary piping top manifold read 5psi. Eventually went to 0psi. First thought was major air still in the system. I shut everything down and went zone by zone to see what kind of air was in there. Quickly found out there was a lot of air remaining. I spent a couple of hours letting the zones flood until I could see no air pockets bubbling in my 5 gallon bucket. I let it run several minutes each after the last sign of air. I was able to get 5 out of the 6 zones air free. I could not get one of the radiator zones unblocked. There was NO water coming out of the drain end on the manifold. I ended the night with that one zone unfinished...frustrated.

Two questions...

1) How can I get the air out if it remains blocked?? Any tricks of the trade?

2) Can I connect the Goldline SP-30 set point controllers to the TT connection on the new boiler? There are 6 low voltage connections on the controller (C, R, 1, 2, 3, 4) as seen in the attached pic. I am wondering if 1/2 are contact points that would close the circuit and message the boiler the in floor sensor is calling for heat and the pump is running? Please note the awful wiring job was done by the original installer. I have corrected with conduit and box connections on the new install.

Thanks in advance for the help. I welcome constructive criticism on any of the project. My biggest regret is that I did not size the secondary line at 1 1/4".

hot_rod

purging can be a challenge, isolate the system into bite size pieces.

If you have a large radiator loop it can be tough to get a good flow rate to evacuate all the air from those large vessels. Do they have working air vents up top on the radiators? Those work in conjunction with the central air purger.

The initial purge assures that you have flow in every loop. The central air purger works for days, maybe weeks afterwards as the water is heated, additional air needs to be removed.
Also water needs to be added behind that evacuated air. Is the water makeup valve left open? Gauge pressure staying up?

Usually heat at the radiator tells you you have flow. Cold rads and excessively hot pumps indicate a no flow condition.

OUBrew

Thanks! There was initial heat at the radiator and then went cold. The air must have moved through the line and blocked the flow. It is on the longest run...maybe 100-120' on the entire loop. There is an air vent at the top of the radiator.

hot_rod

Yep, air will find it's way to the highest point, even when the circulator turns off. Is it a good working automatic vent at the radiator? or manual?

OUBrew

No..unfortunately it's a manual vent.

OUBrew

I did open it last night when I was getting no return water on the drain side and there was a steady stream of water coming out. No air. The air must be locked after the valve and before the drain. Pretty simple loop...a few bends but nothing crazy

Ironman

You need to get the pressure higher for purging - around 25 psi. The fill valve may have a manual bypass. Opening that will introduce full house pressure into the system, but you need to be careful because the relief valve will pop at or near 30 psi. Sometimes, it's a two man job: one has to keep an eye on the pressure while the other purges. Or, you can install a Caleffi fill valve which allows one man to do it. You just set the dial to 25 while purging and back to 12 - 15 when done.

Does the system hold pressure with make up water turned off?

OUBrew

Thanks. I will check that tonight and get back to you. My thought is yes it does.