Adding radiator after modulating boiler installation

Brad White_200

I would install tees in the mains with valves "ready to go" for the new radiator. This way you will not have to drain anything at all. Just tie in the new radiator, add a drain valve to the runouts if you like, fill, bleed and vent. You are in business.

So long as the radiator you install matches the others in type (cast iron to cast iron versus fin-tube or panels), you should be fine. Mixing different types with different thermal masses will show up with the low-mass served rooms feeling cooler.

(Constant circulation mitigates this, especially if you have thermostatic radiator valves. If you have outdoor reset on top of this, you may have a bit of the cold room effect from time to time.)

If the manual says do not use petroleum based compounds or it will void the warranty, I would not argue that point. Do what they say. Life is short enough as it is.

Yeshwant

Replacing radiator after modulating boiler installation

I am having a new Knight mod/ con boiler installed in a hotwater system. At a later date I would like to replace one of the radiators in the house which happens to be a steam radiator, with a hotwater radiator, as is appropriate. Are there any problems with this? Do I need to take special precautions or procedures apart from turning off the system, draining it, replacing the radiator and refilling the system? Are there any compounds I should not use (the manual mentions petroleum-based sealing compounds). Is it true that this could void the warranty?

Yeshwant

anyone care to help me?

Yeshwant

Can you give examples od petroleum-based compounds?

Pipe dope? Can it be safely used?
All my emitters are cast iron radiators. We will have ODR, but not constant circulation. The boiler is sized to run more time than not. Thanks.

Brad White_200

Just look at the labels

Some pipe dopes use mineral spirits as a solvent. Properly done, little if any should get into the lines. I imagine the prohibition or caution may have more to do with certain types of glycol but just the same, check the labels. If in doubt, call the manufacturer who places restrictions on that.