Proper Operating Temperature for Weil-Mclain boiler

RickCol

I have an older Weil-Mclain CGM-4 boiler feeding a radiant in-floor heating system using Entran II tubing. There have been many problems with Entran, and lower water temperatures seem to be recommended to extend tubing life.



The boiler internal thermostat is set to 140 F - the lowest setting. The boiler temperature gauge reads aroudn 132F. The hot water copper tubing connecting to the Entran is reading 92F on the surface of the tubing.



Are there proper operating temperatures?



My heating company says there is a problem and that I need to install a recirculating manifold to lower the water temperature - for a cost of $2000. I think I am being sold a bill of goods ...

Zman

Condensing boiler

The way you have your system set, you are causing condensation in a non-condensing boiler. The condensate is acidic and will eat the boiler and flue pipe.

You are correct that you should run as low a temp as possible in your tubing. Running lower temps will also  lead to greater comfort as the system will only heat the floor as needed and will overshoot your indoor temp less often.

I would suggest a mixing setup with outdoor reset.

If you elect to not upgrade, set your boiler so that your return water temps are greater than 140.

Carl