Best Of

Hydro coils are hard to dial in. What I have found works is once you get your outdoor rest in the ballpark is try reducing the water flow rate through the coil. Up to a certain delta T, the heat output (ie supply air temp) does not change much but you get much lower return water temperature which is what matters for condensing efficiency.

You might appreciate the "beestat" phone app. It can display the ecobee data in various ways, time to heat, estimates temp loss based on outdoor temp, etc. This all can be informative for fine tuning of those supply temps or outdoor resets curves.

Maybe this video will help you a bit, not the greatest IMO, but maybe better than nothing. Looks like his gas valve was failing but he never measured the voltage applied to it.

What does your flashing error code indicate ?

https://youtu.be/5jZBFqZdlFw

It sounds like a one hour lockout. There should be a code while the fan is blowing cold. Time to break out the thermometers and manometers.

My HVAC came he checked few things here and there and suggest to replace the heater 

Another Salesman!

Find a different service provider.

Where are you located?

9 flashes does not seem to be on the error code list, so it may be the control board, its not happy with its self. It may be failing solder joints on the board.

Then @pecmsg's advise is not for you. He was referring to the water side as far as adding chemicals.

Let me read the manual to see if there is a maintenance procedure that will work for you.

Yeah, that "someone" was me. Check the back of your low voltage circuit board like I described above. If that looks OK and if you stay connected with us, we'll move on to the next thing until we figure it out. That's the way it works here.

I agree with @Ironman.

I had an issue with my own house LOL.

Had an old boiler with a Monoflo system 1 zone. The system had a Taco 110. When that failed I put in an 007 and it worked fine.

When I sold the house, I put in a new boiler and an indirect used the same 007 but now had (2) 1" zone valves, indirect and heat. I had put in Honeywell zone valves with a Cv of around 5 I think.

Heating load was only 50 K with a 1 1/4 Monoflo loop. Sounded like a low pressure drop to me. On DHW it was ok with the indirect near the boiler.

On heat the 007 just wouldn't do the job the water was real sluggish getting around the main and this was without the indirect calling.

I took the Honeywell's out and put in 1" Taco valve I think the Cv was 7.5 or 8 and that solved the problem. Maybe I could have swapped to a larger circ for less $$$?