radiant w injection using zone valves?

clammy

Just looked at a job with loads of issues amd of course one of them is the radiant ,being those i usua;;y that i work for dont every do more then a manual mixing valve (cheap)this threw them for a curve nd being others have came and went all w the same thinking that its messed up .Seems the original contractor had the idea of using standard zone valves as a injection using the boiler pump which also serves about 8 other baseboard zones .Each rafiant zones is using a tekmar set piont controller issues from my quick look was #1 tee s for the injection are about 12 to 16 inch apart w one tee being after a few 90 ,no check or balancing valve of supply so theres alot of migration and the supply temps are pretty hi ,no and i mean no temp gauges any where except the one that came w the 285 btu boiler also no purge valves ,also the supply sensors for the tekmar are on the return instead of the supply guess cause that was the only way to get the loop temps up .I,m a little hesitant on the design being no zone is over 1000 sq ft and of course all 4 zones are all 3/4 through and through .As for straighting out i fiqure on the possiblitly of piping the injection tees w properly spaced tees and adding a spring check and balancing valve on the injection loop and of course some temp gauges or am i better off just bagging that low budget zone valve injection system in loo of some i series valves of yeah no return temp protection .On another note boiler water was quite orange and of course drastically oversized beyond belief also the tubing is black .Is all that worth it to repair and salvage or just thrash it .It always amazes me how million dollars homes in my area have the crappest radiant systems on the planet and the owners are as cheap as sin when it comes to heat .in all cases the kitchen or the driveawy was 80 % more then the whole ac or heating system guess people look garbage espically when no one see it .Thanks for the vent peace and good luck clammy

hot_rod

Black tubing as in rubber tube? How old is the system? How oversized is the boiler? Setpoint controls instead of room thermostats?

Injection mixing is a viable strategy, which tekmar control? Some of those early versions are obsolete.

Sounds like a can of worms, make it worth you while and be clear on their expectations.

clammy

Oninix w barrier system is 21 years old boiler is 285 i didnt get the model # but they had tekmar dial type stats ,the controller just has lights no digital display i really didnt start digging into the controls i was to dizzy looking at the piping and the injection attemp .The worse part is the guy piped everything behind a piece of plywood so the injection piping goes out of the zone valve directly behind the panel and then comes out directly into a tee and of course every tee and 90 have no give no foresight .Boiler is maybe 100 or so over what they need .Have to see if they want to spend and go corrective or go the break and react method which is quite common .Alot of big living goes on no need to fix until its a huge issue then lets band aid cause where moving soon lol I personally wonder if it can be straighten out by a little corrective piping byrepiping the inje ction tees properly and adding a chk on supply and balancing valve and putting the supply sensor on the supply also adding some temp gauges .I just wonder how much those zone valves will cycle open close and cycling the boiler also it s all 20 plus years old whats ur thinking right track on corrective being re do wont happen peace and good luck clammy

hot_rod

The ZVs will cycle depending on how much "temperature' they need to inject. if the boiler temperature runs close to required SWT then less cycling. if you are mixing 180 down to 100 for example they would cycle more.

Tough to jump into systems like this without the original design and load calc. It could take a day and $$ just to reverse engineer e and confirm the system was ever calculated and designed to the job. And if the building has changed in the 21 years, a new load calc should be the first step.

I think any controls of that vintage should probably be upgraded.

I'd look carefully at the condition of any cast boiler connected to rubber hose for 21 years. Any indication of previous service work, failed expansion tanks, for example may indicate O2 ingress.

Has the system performed well, any cold rooms, excessive fuel costs?