I put this into the radiant heating category because I use radiant heating in my house, but it is not the root cause of my problem. I am seeking advise as I have three different companies looking at my setup and no one agrees on what the problem is and what the solution could be. So I figured I might post my issue here and have the feedback of professionals which are not trying to upsell me a solution
So, during my house reno, my GC used a heating company to set up the radiant heat system on the main floor of my house. My house is pretty small, main floor is an open space with radiant floor heating and the second floor is using cast iron radiators from the 40iest.
The system is setup like this:
- Zone 1 is my radiators upstairs. The thermostat is upstairs in the middle of the landing next to the staircase. The rads are old and the valves are seized in an (wide?) open position.
- Zone 2 is the heated floor. The thermostat is in the middle of the room.
My boiler is a McLain ECO 70 from 2018.
The thermostats are connected to a Taco SR502 2 zone switching relay. My zone 2 has the Priority jumper on (no idea what that means though...).
And that is connecting the two pumps: Grundfos UPS15-58FC.
Here is what is happening:
When it is cold outside at night (goes below 0 Celsius) the rads upstairs continue to heat even if the upstairs thermostat reached the desired temp. Well, even if I turn off the heating with the thermostat, it continues to heat like I it has literally no effect on controlling the temp (my GC changed the thermostat twice thinking it might be the issue but it did not change anything).
The only way I have to lower the temperature upstairs is to set my radiant in the first floor to something like 18 Celsius. Only then I can see the rads getting less hot and eventually stop heating.
The people who installed it play dead.
One said that we need a valve in front of the pump of Zone 1 to stop the water to flow. Cost ~1K.
One suggested to change the position of the Zone 2 pump and was not happy with the whole spiderweb look of the setup from the boiler to the pumps. Cost ~1K.
One suggested to replace the seized valves by thermostatic valves on all the rads upstairs. Cost ~1.2K
Well the last option was also suggested by the first one in addition of putting a valve before the pump.
They all gave me very different explanations of the issue. Sometimes contradicting each other.
I know you can't troubleshoot the thing from the Internet. But I am still curious to know you opinion on what could be wrong here or what question I should ask. And I can provide more details and photos if that helps.