Caldera Niagara with no heat and only circ pump working. How to diagnose?

[jasolution]

Here is a video showing the issue

https://www.youtube.com/watch?v=1E39q_Alazw

The heater display works and when you press pump 1 and 2 buttons or air button, the LED symbol displays like normal, but the pumps don't actually turn on. The circ pump IS running, but there is no hot water coming out of the heater.

Here is a pic of the lights that are lit on the control board when I open the panel cover http://screencast.com/t/drM9ux8iq1

I have power cycled the unit and removed the filter (which was very clean).

Thanks!

[Chas]

The most common reason for this is one leg dropped from the 50A breaker which feeds the sub panel. When you power cycled, did you also cycle the main breaker which feeds the sub?

If one leg trips only, and if you're lucky enough to get the correct leg, the control system and lights can continue to operate (circ pump included), but no heat, no jets.

The breaker usually has a single handle which controls two breakers, and one leg CAN trip without tripping the other, though it's not supposed to happen. Turn off the 50A firmly, and then turn it on. If that doesn't fix things, you will need to check to see if the breaker is bad, or a wire has fried. An electrician would be a good person to have check those items...

HTH

 

[jasolution]

I was hopeful that this was the problem, but I tested and am getting 120v on each of the leads at the hot tub. Just for kicks I also replaced the 50 amp breaker in the main panel, too.

When I press the button for pump 1, pump 2, or the air pump, I hear something clicking on the main control board, but the pumps never fire up. I pulled the heater relay board out and while I couldn't do any actual testing on it, there are no burn marks anywhere on the front or back. This one has me stumped!

Jason

[Chas]

Well, 120 on each lead at the hot tub is not a valid test. You need 120 to neutral on each hot, but you also need 220 from hot to hot.

You may have a bad wire, or a loose connection.

 

[jasolution]

Ok, so I'm getting 120 volts on each hot to ground, but only 37 volts from hot to hot. Would this indicate a problem within the relay board or upstream in the subpanel?

Thanks!

Jason

[Chas]

This could be sub panel or main house panel -

Check that both sides of the breakers have 220 between them - at the main panel first, then the sub panel.