Lochinvar LVL065g -- Resetting after blowup.

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I need help in getting this HWH restarted. This model does not have a pilot light, and is an ON-DEMAND ignition, and Honeywell controls.

STATE today:
-- Heater heartbeat comes on with power, and NO call for heat, showing no errors -- [one flash / 4 sec]
-- Call for heat, starts blower, heartbeat shows normal, with no errors. [on/DIM/on/DIM///etc.]
-- Fan runs for five minutes like this but there is NO fire, and no visible spark in sight glass.
-- Fan pressure switch circuit in fan closes, and voltage that started at ~ 12v goes to 0v, showing that both the FAN temp and the pressure switch is working when the fan is ON.
-- Flammable vapor sensor reads 17k, I think. NOTE, I SEEM to remember it was at 50k?? a few days before?? I mention this, since I may need to reset this on the Honeywell controls, and in any case, I KNOW that it was exposed to raw propane recently.
-- TIMES OUT after five minutes, with SIX flashes, / 1 sec / ONE flash / 3 sec --- NO "pilot OR ANY flame/light or ignition sparks seen at all. Remember, this is POLOTLESS ON DEMAND ignition.
-- Flashing of 6/1 stops after five minutes, and then it RE-tries again to turn on the fan and light the gas, which fails again after 5 minutes.

-- open combustion chamber to check alignment of ignition wire and fuel.
-- Check operation of spark, since I had to solder a new connector on where the ignition wire went into the control.

-- Looking at some of the SERVICE TIMING DOCs, if there is NO power and there is NO gas pressure, and then you REAPPLY gas, it spews a startup of raw propane of 10 (?15) seconds. But, there is NO MENTION of this PRIMING the chamber on any warning label on the HWH, or in the manual.

The instructions cover these two procedures, but not one that is CRITICAL:
1. Turning power BACK on, (ASSUMING that the gas pressure was NEVER REMOVED).
2. Turning GAS OFF
3. [[ They FAILED to say what the procedure was, of how to TURN the GAS BACK ON, after depressurized. ]]

You can guess what I did after repairing a huge leak in the piping from one of the two regulators in the system, one of which was not in service but connected to the system, and 20 years old.
1. I turned the GAS VALVE to the HWH to ON, which had NO PRESSURE on it at all -- As expected, it hissed as it filled / re-pressurized the hoses and HWH. But, what I did not know, nor did it tell me, it primed the chamber with raw propane!!
2. I smelled NO LEAKING GAS.
3. I turned on the power to the HWH.
4. BOOM!! --- The chamber was PRIMED with raw gas, just from REPRESSURIZING the HWH, with NO power. Within 5-10 seconds I turned the power on the HWH, which immediately ignited the gas in the chamber and also in the exhaust fan that was not yet running. It blew 3 - 5 pieces of the exhaust fan enclosure all over. I immediately turned off the gas valve to the HWH, and blew out a small insulation fire on the gas hose covering. IF, AFTER turning the gas back on, ASSUMED correctly that there would be a lot of RAW gas

In this instance, I manually turned the HWH power to ON, after re-pressurizing the gas.
But, imagine if I had a whole house propane-based generator, and ran it completely out of gas
, like would occur in a hurricane. As soon as there is some gas back in the lines, the HWH would immediately PRIME the chamber. If, within 30 seconds I restart my generator, unbeknownst to me, that would trigger the SAME EXPLOSION and FIRE by the HWH. Only this time, I would not be there to to see, or blow out that small fire.

The SANITY check I'm requesting is, why it is this designed this way?? After I got everything as back to normal as possible, the lines were RE-pressurized again, and it primed the chamber again for 10-15 seconds, only I had a FAN blowing on the HWH, with the garage door open, and I did not add any power, until I could not smell gas and waited over 15 minutes. I then tried to get it to start firing up and failed. But, there has been pressure on the HWH now for several days, with no leaks.

I need to ensure that I'm not missing anything, before talking to product managers at Lochinvar about their oversight that I think needs correcting. Am I dumb, or maybe they at least owe me for a fan that shouldn't have blown up?
Hey, wait a minute.

This is awkward, but...

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