Harman P43 not working with UPS

[TheGeneralLee]

Hello all, happy new year.

I've been running a P43 harman the last couple winters and one issue I have is if we lose power at the house while the stove is running, smoke slowly leaks into the house. I do have a vertical run on the exhaust of about 6' but it's mounted on the north side of my house where the wind usually blows so I suspect that's why smoke comes back in the house.

To help prevent this issue, I bought an APC 750 UPS, the one recommended by harman. I let the battery charge, then pulled the UPS plug to test running the stove off the battery. It didn't work. The stove's blower "throttles" up and down like its struggling with low power. To troubleshoot the problem, I even tried a larger 1500 UPS and found the same result.

It's important to note I'm testing the UPS only when the stove is running, not at start up. I understand the igniter draws too much electricity for a UPS. I never plan to use the UPS to start the stove, I just want an extra few minutes to properly shut the stove down when we do lose power.

Any ideas why my P43 isn't working with the UPS?

 

[bogieb]

Hmm, I just tested my P43 (it is in the process of shutting down right now) and had the same thing happen. I don't know if that is normal as I never tested my P61a either (an oversight on my part). However, it is important to note that the Harmans are not supposed to "run" on the UPC, but rather shut themselves down gracefully. Maybe that is how they save enough juice to go thru the 15-30 minutes worth of fan needed for the exhaust?

I would be curious to see if this is the way it works for others with Harmans. In the meantime, I'll go check the P61 . . .

 

[bogieb]

Yep, the P61a (which was already shutting down too), also does the fan off, bump of fan, fan off, bump etc. This stove has enough vertical run and almost no horizontal run that I'm not worried about smoke too much - more about protecting the electronics.

However, the P43 has very little vert. run so I do somewhat worry about smoke. I actually got my UPS for the main floor since the previous Hasting DID leak smoke badly at even a power flicker, and it would run normally on the UPS. Unfortunately, the P43 was near the end of the shut down (no live coals), so didn't get to see if there was an issue with smoke. Will try it again later though.

 

[Harmanizer]

It's normal for the Harmans.When they detect a non sine wave input they go into controlled shut down mode which pulses the combustion blower to help remove smoke.I remember reading about it in my manual.

 

[Harmanizer]

Found it.Page 34 of my manual.When power is lost a fully charged UPS will power a safe,combustion blower only shut-down.Your appliance will pulse the blower every few seconds until the fire is out.

 

[bogieb]

I knew it said it would shut down controlled, but didn't recall the it mentioning the pulsing blower. Frankly, to lazy to look because I thought my memory was perfect (as if - LOL). Thanks for the confirmation!

 

[lbcynya]

Your stove is responding as designed...

 

[gfreek]

Your stove is responding to a non perfect (modified sine wave) type of power., as stated it goes into shutdown mode. Harman started doing that a few years back on their models.. If it was Pure Sine Wave, it would stay running as normal...If I'm wrong someone correct me please.. Pure Sine Wave UPS are more expensive....

 

[bags]

As already mention it is normal for the pulse bump of the exhaust blower just to evacuate the smoke as the fire burns down. I never tested mine either and we had a power outage here last week due to the rain and storms. It caught me off guard some to because i thought it would run more consistently during the shut down. I had read the manual but long forgotten what i read about the UPS.

I have an APC 750 for my P68. It shut the stove down fine and did the bump of the fan off and on in cycles for some time as the fire took quite awhile to burn out. Sounds and acts weird at first just because it's different.

 

[TheGeneralLee]

It's normal for the Harmans.When they detect a non sine wave input they go into controlled shut down mode which pulses the combustion blower to help remove smoke.I remember reading about it in my manual.

Thank you very much for the quick reply and thank everyone for the follow-up comments. Question answered perfectly, I appreciate the help. Stay warm!