HELP! Hooking OWB into existing boiler with domestic coil using plate exchanger

[dparkguy]

Boiler is ordered and I'm in the home stretch of hooking things up. I have a domestic hot water coil in my existing boiler. If my thinking is correct, I need to circulate the water through the plate exchanger and the existing boiler to produce domestic hot water using a "bypass" circulator. So far so good? If a heating zone in my house calls for heat, the "bypass" circulator would have to turn off using a zone valve and zone valve controller. Then my primary circulators would turn on and circulate the hot water through the plate exchanger and then to my hot water baseboard or radiant floor system. View attachment 300074 The two primary circulators are labeled in the picture. I would like to see pictures of this kind of setup. Any help is much appreciated.

 

[NSMaple1]

Would the 'bypass circulator' need to turn off?

(Not exactly sure how you're tying into your system).

My first thought is the 'bypass circulator" would heat the existing boiler, by circulating through the heat exchanger, whenever its temp drops below a certain setpoint. That drop could be from standby losses, DHW use, or a heating zone using heat - so not really sure of the need to interrupt its pumping. Sounds like maybe to get more direct flow to the heating zones - but if you need the boiler to stay hot for DHW anyway, I'm not seeing much of an advantage.

My boiler experience is limited to inside ones though, and not OWBs.

 

[rugies]

Hi if you have your primary boiler water being heated by the heat exchanger coming from the owb then that should heat your domestic coil.

 

[rugies]

I didnt say that right. all you have to do is put your heat exchanger into the circulation of your boiler. The exchanger will heat your indoor boiler water and all funtions will remain the same as they did prior to hookup of owb heat exchanger.