Old Stove Sentry SF503A Backup for Harman P Series Stove?

[lowb35]

I just upgraded this year from a Heatilator/Quad CAB50 to the mighty Harman P68. I like not having to clean the stove every.single.day beyond scraping the burnpot and after getting used to the brief nuclear reaction in the firebox on startup, it does a better job of maintaining a set temperature in my house.

I have a question about the battery backup system. I have a Stove Sentry SF503A with a deep cycle marine battery that was my backup for my old stove. Even though the unit was manufactured quite a while ago, I bought it as new old stock so it's been in use for 5 burning seasons total so far. I was prepared to swap out the inverter when I got my new stove, but the dealer said that my current system would work just fine with my Harman. When they installed it, they set the dip switches to run on a non-sine wave battery backup so it wouldn't go into shut down mode. However, I wanted to double check on this since the Stove Sentry SF512 was the one specifically designed to work with Harmans, while the SF503A was more generic for "any" (older) pellet stove with an igniter.

I've seen some older forums indicating that the SF503A which puts out more power could also be used with Harmans. While both these units are modified sine wave they were designed specifically for pellet stoves and since the P68 is using older technology I *think* it will be okay (no way I'd use it with a more modern digital display or wifi enabled stove) but wanted to see if anyone out there has ever seen this specific inverter used with P series stoves.

This is where I saw that the SF503A was OK for Harmans, but it looked like it was being used with another model stove. https://www.hearth.com/talk/threads...izing-modified-or-pure-sine-preferred.139504/

Edit/Update: I contacted SEC America and they said that the SF503A wouldn't hurt my stove. They recommended their newer pure sine wave unit (Model 933) but since my stove is already configured for non-sine wave backup I'll stick with what I have for now.

 

[Ocelot]

That's a good question. I think it would depend on how clean a sinewave it puts out whether the stove would see it as too modified and trigger shut down or not. I currently use an old APC Smart 1000 UPS on mine and it will run the stove for over an hour, depending on how high it's set. I have a 5700 watt gas generator on a manual transfer switch for 6 circuits, and I like the APC UPS because besides voltage regulation, it completely filters the input voltage if I need to use the open-frame generator for any length of time.

I don't remember the exact numbers, but on my Harman P43, the running watts varied from the 90's to just over 100 watts and would jump up slightly when the auger motor would run. I haven't tried it with the igniter, but that's only 306 watts additional, so it would run that as well.

My plan when the APC ever dies is to use a good quality inverter with a UPS function and some LIFEPO4 batteries which would give many hours of use.

 

[lowb35]

Supposedly even the older SEC America units were developed to work with pellet stoves so even though they're modified sine wave, as long as the P68 dip switches are configured correctly the stove will continue to run. I just wanted to make sure the power quality was similar between the two units. The SF503A can output up to 750w and the only reason why I'd switch to manual is to extend battery time. I think the longest I ran my old stove on backup was 6.5 hours. The power draw on the CAB50 was 5.1A on start and 3.0A running according to the manual, so a bit more than the Harman.

If I upgrade to the new inverter, I'll also go LIFEPO4. I have an AGM deep cycle battery in a battery case which is about as safe as you can get with that style of battery, but LIFEPO4 batteries run so much longer that it would be worth the upgrade. Otherwise I'll stick with what I have for now. I know there are less expensive options but the SEC America inverters are very heavy duty and simple to set up.