Multiple heating element failures

[wayneskid]

I'm posting (for the first time) on behalf of a friend with an "interesting" problem.

The heater is a Bradford-White 50 gal. low-boy heater that supplies hot water to the in-floor heat loop for a concrete floor in a detached shop. The house and the shop are supplied by a private well. They are located near Bend Oregon.

The system was installed in 2011 and in 6 years the installing contractor has been called out 4 or 5 times for failures. Each time, one or both elements were found to be bad. Each time both elements were replaced.

I happened to visit shortly after one of the failures and found:

• The wall tstat was calling for heat
• The circ pump was running
• Ambient temp was 60 F
• Both hot and return manifold temp was 45 F
• Voltage at both elements was 240v
• The upper element measured open
• The lower element measured 13 ohms
• The lower internal thermostat was closed.
• Strangely, the upper internal thermostat was open, even when its temp setting was turned up.

The contractor seems unable to sort this out. Any bright ideas from the plumbing wizards?

Thanks,
Wayne

 

[phishfood]

Something does not sound right.

If the upper thermostat is open, you should not be getting 240V at the upper element.

You should not be getting 240V at both elements at the same time.

If the ECO is tripped, you should not be getting 240 anywhere below the top of the upper thermostat.

This is not making sense to me.

 

[wayneskid]

I see your point phishfood. I may have scrambled my notes, or something may have changed between the voltage measurements taken with power on and the resistance measurements taken with power off.

I'm in Alaska and my friend's place in in Oregon so I can't just hop over and check it out.