Using a boiler DHW coil as a HX for a hydronic loop?

delcrossv

Settling in on a 19HE as a replacement boiler and in my size range I can order with up to two DHW coils. Can those be used as a HX for a hydronic loop ? That would solve dissolved air entry into the loop and associated corrosion issues.
In this case I'd just pipe it like a conventional HW loop? (compression tank etc?) but with a bypass to adjust temperature?

mattmia2

Yes. Aquastat on the boiler to heat it for the hot water loop but not cause it to steam on a heat call. Needs a relief valve.

Don't need a bypass in most cases, what do you think you need it for?

Hap_Hazzard

This article discusses various options for running a hot water loop off a steam boiler. The Systems Help Center has some other articles you might find helpful.

Derheatmeister

We installed a reverse indirect on a system without o2 barrier to mediate between a Viessmann and PB tubing..Works great.