Grab some popcorn!
I purchased a bi-level house in 2016 that has all infloor radiant heating. It utilized a heatmor manifold system (mounted in a hallway and in the garage) with 4 loops for upstairs, 4 for downstairs and 2 in the garage. The heating source was a water to water radiator with an outdoor wood burner and had a 40 gallon water heater as a backup. The house was built in 2001 and the heating system was never really service.
100% of the valve systems were clogged and none would open or close, so those were the first things to be ditched, the electronics for the pump control (1/25hp groundfos) didn't work correctly so basically I ran it on max temp test mode to kick the pump on.
The 1st winter was pretty awful, the wood burner was also neglected and didn't work right, so I tried using both the wood burner and the back up electric water heater, but the first month my electric bill was over $500 dollars, so the electric water heater wasn't used again.
Fast forward to Sept 2018, the backup electric water heater started to leak so it was time update the system.
I piped in a takagi propane unit in place of the electric water heater, so I could use that as my main heat source and keep the wood as a backup, so I piped in a ball valve to partially by pass the water to water radiator for the wood burner. I wanted to keep some heat going outside to help keep it from freezing.
However I've ran into some issues. I cannot get more than 1gpm flowing through the system (the heatmor manifolds don't have individual flow meters, so the takagi was the first time I could see flow). I tried burping the system, closing the garage loops off, different pressures, 1/6hp pump, and a few other things. For a while I was getting about 2.2gpm through the takagi and that seemed to be perfect.
Since I was going to be home all week I decided to burn wood and turn the propane off, but now I am only getting about .5-.7gpm and have gone through burping, changing valves, pumps, etc. for the entire system again and nothing seems to work.
I've been able to hook a hose up to the valve on the cold intake side of the takagi and it bumps the gpm up to about 3.0gpm but comes back down slowly. I've messed around with this for 15+ hours over the weekend so far and am out of ideas!
-Water is seperate from wood burner, and wood burner has antifreeze in it as well.
-The system has 2 pumps, a 1/25 grundfos and a 1/125hp recir pump on the cold side, all valves/zones are open.
-There are no flow meters at the manifolds and I have 2 pressure gauges on the cold/hot side when I added the pex.
-I had the 'radiant heating guru' company come in and check everything out in 2015 and they were absolutely no help and only helped take about $200 bucks out of my pocket to say "well it looks good to me!"
-With flow averaging about 1.1gpm I ran through 8 gallons of propane per day from my last fill up. The takagi is the only propane appliance. House is about 1700sq including the heated garage and it was probably an average temp of 32F during those 35 days.
Here is a google drive link to pictures: https://photos.app.goo.gl/SRmWd6W7iaVSeZFF8
Please let me know if you have any suggestions, concerns, or ideas to help increase the flow of the system!