Intermittent ignition lockout?

[Kevin Lawson]

I just hooked up my brand new HTP PH79-50 and I'm getting and F01 ignition lockout code intermittently on the new water heater. Sometimes it will fire on the first attempt, but this morning I had to hit reset 4 times to get it to fire.

Gas: 10’ of ¾” BIP to from the regulator to the inlet of the water heater. Static Inlet pressure = 5.54 in W.C. Dynamic inlet pressure 4.99 in W.C.

Air: 75 equivalent feet of 2” pvc flue piping. When I pulled the flex collar off the inlet the water heater failed to ignite once, and but then fired on the next reset.

Ignitor: Ignitor cable connections are tight. 951 ohm resistance, sparks are observable when you hold the ignitor close to the ground plate. Ground on everything is good.

Model PH79-50 Release 014 Revision 000

Any advice?

 

[DonL]

Air: 75 equivalent feet of 2” pvc flue piping. When I pulled the flex collar off the inlet the water heater failed to ignite once, and but then fired on the next reset.

Do you have plenty of makeup air ?

Good Luck.

 

[Sponsor]

 

[Kevin Lawson]

I spoke with HTP technical support this morning and we resolved the issue.

For future reference: I was running the water heater at low temp (around 112 F) to squeeze every last btu out of the system. This would cause a lot of condensation. The (ceramic?) insulation that surrounds the ignitor was wet from the excessive condensation and it was too close to the ignitor. The spark was shorting through the insulation to the grounded frame. I rubbed off some of the insulation around the ignitor and it fired right up.

It seemed that it was a lot harder to get ignition at lower temperatures, after the heater had been off for a long time. I thought the low temperatures caused the CuNi heat exchanger to contract and be too close to ignitor so that the spark was jumping to the heat exchanger instead of the burner. My guess is that when the system was hot it would keep the insulation at a lower RH and we’d have less of a chance of shorting through it.

Anyway, tech support was very knowledgeable and patient.

 

[Kevin Lawson]

Do you have plenty of makeup air ?

Good Luck.

Yea, the manual allows for 150 equivalent feet of 2".

 

[DonL]

Yea, the manual allows for 150 equivalent feet of 2".

For Fresh air or Exhausts ?

Do you have pictures ?

Good Luck.