The idiot tries to drop voltage...

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I think we are sorted now.


It seems to have been a combination of the high voltage from the street coupled with the meter not able to measure the resistors properly. Under load, they seem to be doing their job properly.


Today we will do a full test, so the contactors will come into play. I will fine tune it from there and we should be all set.


Thanks again to those who offered constructive help.
 
One resistor for the control system, including the coils.


All is working as it should- with both coils pulled in, I am seeing 484VAC. I wil check it again in the morning, after stuff has "burned in".


I am not seeing a significantr rise on tank one yet... Might be a thermocouple wire problem. I'll check the temp again in a few minutes and again tomorrow.

Timer shuts it down about now (5:00PM) and it will turn on again 6:00AM tomorrow.
 
Trying to drop AC voltage to an inductive load with a resistor requires a quite different resistor value than dropping to a resistive load. The voltage drops across R And L (coil is mostly L) add at right angles to one another. I would probably try to find a big 100 watt dog-bone style resistor on the surplus market - relying on a 5 or even 20 watter being run close to ratings is asking for trouble in the long term.

A transformer is a far better solution. One rated properly for the task, however is usually stupid expensive. Could be a couple hundred for a 50 VA unit - certifications are expensive. That being said I did replace the control transformer in my old AC with a cheap toroid from MCM once. It was the only thing I had on hand with a 240v primary. The whole unit got replaced less than a year later. I wouldn't do it as a long term solution - but it got it running that night. You would need a tube plate supply transformer (500 - ish volts is common) - or the proper control transformer. If you do something like this, put the trafos in its own UL rated enclosure and wire it to code.
 
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