On Oct 17, 12:16 am, wrote:
Dear Readers,
My Burnham MPO boiler was installed in August. I've an indirect water
heater attached as well. The domestic hot water works fine and heats
up on demand as expected. Now that heating season has begun, I find
hydronic system with very very weak heat output. The new circulator
is running fine. The manual says there is a 15degree differential
between the "high limit setting" and a call for boiler ignition. I
see the high limit is set at 200F. I raise the thermostat to call for
heat, but I watch the boiler thermometer go down to under 90deg F and
never come on. The only way it does come on is if I run the hot water
too.

Any ideas or suggestions on what is wrong would be appreciated.

Regards,
Anthony Falcone

In the end, the DHW was properly wired to the relay. However, the
hydronic heat loop was not so properly wired. Furthermore, there was
a TON of air in the system and we had to bleed it out about 5 times
over 3days.

Thanks very much to all for the advice.
Regards,
-Anthony Falcone