water not being heated in water boiler?

Question

Have a Hydrotherm model HC-165 hot water boiler with 4 zones. Occasionally the water temperature in the
boiler drops below the pre-set temperature of 160F even though the different zones are "calling" for hot water.
All thermostats are set to a higher temperature than than the temperature in the house. Water flows
from the boiler to the different parts of the house, but its cool water.
I check the temperature in the boiler, and its around 60F. Confirmed all transformers connected to
the boiler are outputing 24V, NG pilot light is on, zone valves that control water flow to the different
parts of the house are open.
If I reset the circuit breaker switch for the boiler, it fixes the problem. Boiler starts up and the
water inside it gets heated up. works fine for a few days or weeks and the problem re-occurs.

A while back I replaced the thermostat that plugs into the boiler but that didn't fix the problem.

Any idea what could be wrong?

I bypassed the tstat (crossed the 2 wires going to the tstat) and still the same results. There are no safety switches.

Answer 1

really doesn't matter,

Answer 2

The circuit breaker trips it is not big enough for the load or some load has a small internal short. Check your load requirements by checking ever thing that is on the 24 volt circuit and seeing if the total amperage is smaller than the "VA",/24, rating of the transformer your fine there. Then look at finding a short.

Not knowing your electrical background I need to ask you if you are not confusing a circuit break for a roll out safety switch. The safety switch would be down by the burners.

Answer 3

The new tstat may be bad get a volt meter and see if the contact is made through the tstat. If this contact is made check the over temp safety switch and all other safeties in the circuit