Converting a steam boiler to hot water

Last year my old boiler finally kicked, I purchaed a Smith GB200 in a pinch to replace it. I was wonder if it was possible to convert my steam boiler to hot water. I know i have to get rid of the pressure and low water switches and put in a temp switch, but will the boiler handle the higher pressures? Will the 2" outlet being reduced affect the boiler? I do plan on replacing all the 1 pipe radiators and pipes with new baseboards, I just hate to have to get another new boiler for this.

 

To be certain you need to contact the manufacturer. Sometimes hot water boilers will have internal baffles that a steam boiler does not have.

ASME code, Section IV (Heating Boilers) specifies a maximum allowable working pressure of 15 psi for a steam boiler and various pressures for water boilers. Most low-pressure (sect. IV) boilers are rated 30 psi when in hot-water heating service. Your boiler may be dual rated for 15 psi steam / 30 psi water.

You want to keep the low-water cut-out as long as it is not integral with a water feeder. The pressure switch probably has a maximum setting of 15 psi and that may be too low for hot water service. The gauge glass will need removal and one of the tappings can be used for the aquastat.

Reducing the outlet size will not be a problem.

 

It's a steam boiler - not meant for hot water heating... besides, with it being natural gas, that will be a good chance to get a modulating condensing boiler and really save (>30%) on your heating costs.

 

By the Time you spend the money on parts and controls for the conversion you are already half way there on the cost of the boiler in some cases.

 

WHAT???

As I originally stated you need to contact the manufacturer to be sure but most residential steam boilers are dual rated for 15 psi steam service and 30 psi hot water service.

The only thing necessary to change it over is the removal of the gauge glass and high pressure control then the addition of an aquastat and high temperature cutout. Of course you will also need the expansion tank and circulating pump (with control) but these will hardly be equal to half of what a new hot water boiler would cost.

I would tend to agree with Who that you might be better off with a new modulating / condensing boiler if your plan is to install a completely new heating system in your home.

At any rate I suggest that you very carefully consider what you are planning. Going from 215 degree steam to 180 degree (or less) hot water you WILL need more radiation surface in the house to have the same level of comfort as you now have with the steam. Add to that the enormity of replacing all the existing piping and just installing the replacement boiler may be in your best interests.

 

You think controls for a HW boiler are gonna cost $4000 ? I kinda doubt that. Hopefully he's checked with the manufacturer and gotten good advice from them. Many boilers are rated for both services, maybe his is ... it sure would be a shame to scrap a 1 year old boiler.

 

Just to close the book on this one, the Smith GB200 is NOT suitable for conversion to hot water service. It's single rated for steam. Max pressure 15 PSI. That's what WHO was saying in his previous post...