New Boiler and Piping Questions...

Robert O'Brien

to use for ODR?The 100 doesn't have any.Order the 0-10V adapter and you can use a Tekmar or AQ2000(they should have 0-10V terminals by now) You'll never see 170 supply temps in all likelihood.I prefer Viega Fostapex

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GlenJ

I had some great feedback on the Manifold question I asked a week ago, thanks.

Some background. I am replacing an ancient oil boiler (converted from coal with the Riello burner I'm told) with a Viessmann Vitodens 100. I'm going to re-plumb from the new boiler to the existing cast iron supply lines where they enter through the open basement ceiling. The lines feed 12 existing large cast iron rads.

I think I've narrowed the new system down to the following based on feedback. I will mount the Vitodens 100 on the wall along with the low loss header, Grundfos 15-58 pump, expansion tank, gauges, drain valve, pressure relief valve etc (as outlined in the Viessmann tech guide). I'd like to connect the supply to a 1-1/4" or 1-1/2" copper header that will feed 12 3/4" PEX barb fittings. I'll run a supply line with PEX-AL-PEX to each rad connection and terminate with a 3/4" ball valve (to isolate and balance flow) and a threaded adapter to the cast iron pipe. For the return I'll have the same in reverse...ball valve to PEX-AL-PEX to a return header etc.

Does anyone see any problems with this plan? Can PEX-AL-PEX handle the 170F water long term when run at 20psi? Any recommended brands to use or avoid? Will the expansion of the PEX be an issue at this temperature? Anything I'm missing?

Thanks...