Harman p68 UPS installation for power outage question

[Curtissk]

Thinking about installing an uninterruptible power supply to my 2006 P68 Harman stove. I'm considering only going through the exterior wall about 2' with the vent, and I'm concerned about smoke escaping into the house in the event of a power outage.
I'm not interested in having the stove operating during the outage. I just want the exhaust fan to function for a safe shutdown.
Harman recommends a Tripp Lite Internet 750U. Can anyone tell me if this device would power my stove into a safe shutdown?

 

[bogieb]

I use APC BE850G2 (850 VA 450w) UPS for both my Harman's (here is a link to Amazon). The stoves do shut down gracefully, pulsing the fans to keep the smoke evacuated when power is lost. I actually had that happen the other day as I had a brown out (probably a phase shift or whatever) for a few minutes.

I think these do go on sale on a regular basis (at least the 750's did before they were obsoleted). So you may want to wait and see if there are any Black Friday deals that pop up.

I think the main thing to make sure of when using a UPS for the Harman pellet stoves in this manner is to NOT get pure sine wave - otherwise the stoves won't sense the difference.

 

[bogieb]

BTW, the UPS should work with your older stove without changing any settings unless you have changed the control panel out. Newer stoves (I'm not sure when it started, but after 2014 for sure), may need a change in the dip switches to get the graceful shutdown functionality.

 

[Whitenuckler]

BTW, the UPS should work with your older stove without changing any settings unless you have changed the control panel out. Newer stoves (I'm not sure when it started, but after 2014 for sure), may need a change in the dip switches to get the graceful shutdown functionality.

Do you have any links or other information that I could look at that to read more about this special PWM sine wave mode Harman's use to pulse the fan? I have heard of a stove design (I think, not sure where) that took a special output from a UPS to tell it to it to shut down, but I have never heard of the mode you are describing.

 

[Whitenuckler]

Do you have any links or other information that I could look at that to read more about this special PWM sine wave mode Harman's use to pulse the fan? I have heard of a stove design (I think, not sure where) that took a special output from a UPS to tell it to it to shut down, but I have never heard of the mode you are describing.

Did some digging.

https://downloads.hearthnhome.com/brochures/HAR-0040U-0718_BatteryBack-upOptions.pdf

I looked up some of those Tripp Lites they say are for continuous operation and some are modified sine wave.
You are right some models with a screen have some sort of setting.

They say even a knob stove has a setting on the switches:

https://d3munzpmppxgon.cloudfront.net/1003/resources/1197600.pdf

Not quite sure how this all works but you are 100% correct. I have pure sine wave and a big battery so I have never did any testing. I run on the inverter all the time so when it kicks off I would dead. I am in the basement with OAK so probably would not get any smoke anyway.

 

[Curtissk]

BTW, the UPS should work with your older stove without changing any settings unless you have changed the control panel out. Newer stoves (I'm not sure when it started, but after 2014 for sure), may need a change in the dip switches to get the graceful shutdown functionality.

Bogieb, thank you so very much for your input!! A big concern of mine was if something would need reprogrammed on my stove? I will look into purchasing one of these UPS's. I bought the stove used in 2019, so I'm hoping the previous owner didn't change out the control panel.
This electrical stuff is so above what my brain understands!

 

[bogieb]

Do you have any links or other information that I could look at that to read more about this special PWM sine wave mode Harman's use to pulse the fan? I have heard of a stove design (I think, not sure where) that took a special output from a UPS to tell it to it to shut down, but I have never heard of the mode you are describing.

I do not have info. But, when it came time to replace my UPS, I took special note of the specs on the originally approved UPS units and the differences between the BE750G versus other 750 models by the same manufacturer. That is how I arrived at the BE850G2 as a replacement model (or the RBC17 as a replacement battery)

Versus the battery:

I also may have read it in a post somewhere here - that was way long ago.

 

[Whitenuckler]

I do not have info. But, when it came time to replace my UPS, I took special note of the specs on the originally approved UPS units and the differences between the BE750G versus other 750 models by the same manufacturer. That is how I arrived at the BE850G2 as a replacement model (or the RBC17 as a replacement battery)

View attachment 342608

Versus the battery:
View attachment 342609

I also may have read it in a post somewhere here - that was way long ago.

I did some digging and posted yesterday - I actually had the documents and posted some links at 10:54. I guess what ever I read I had forgotten. Thanks for helping. I'm still not sure how they make it work, the UPS that is not sine wave ect, and do the pulsing of the combustion blower. Somehow the board can detect the temporary UPS power.

 

[mtnbiker727]

BTW, the UPS should work with your older stove without changing any settings unless you have changed the control panel out. Newer stoves (I'm not sure when it started, but after 2014 for sure), may need a change in the dip switches to get the graceful shutdown functionality.

How would I go about changing the "dip switches" on my 2018 P68?

 

[Whitenuckler]

How would I go about changing the "dip switches" on my 2018 P68?

https://d3munzpmppxgon.cloudfront.net/1003/resources/1197600.pdf

You will need to take your card out and verify to this chart. As for making the change, what you will see is a multiswitch
"block" on the card. You then just need to use a thin flat screwdriver to "rock" the switch to another position. According to
the document it is only one switch of the many on the "block"you need to possibly switch.

 

[Curtissk]

Bogieb & whitenuckler,
I purchased a tripplite internet 750U. Plugged the tripplite in and allowed the battery to charge for 24 hours. Then, with my p68 running, I killed the power to the tripplite. Tripplite automatically kept the stove operating for 5 or ten minutes, then the tripplite killed the power completely to the stove. Unfortunately, I had smoke leaking out of my stove. I was hoping that the tripplite would shutdown the stove gracefully, but that didn't happen.
I then purchased a different UPS. An APC 850 VA. I got the same results with it. Any suggestions or ideas regarding why they aren't shutting down the stove gracefully would be greatly appreciated

 

[Whitenuckler]

Bogieb & whitenuckler,
I purchased a tripplite internet 750U. Plugged the tripplite in and allowed the battery to charge for 24 hours. Then, with my p68 running, I killed the power to the tripplite. Tripplite automatically kept the stove operating for 5 or ten minutes, then the tripplite killed the power completely to the stove. Unfortunately, I had smoke leaking out of my stove. I was hoping that the tripplite would shutdown the stove gracefully, but that didn't happen.
I then purchased a different UPS. An APC 850 VA. I got the same results with it. Any suggestions or ideas regarding why they aren't shutting down the stove gracefully would be greatly appreciated

I have not personally used this kind of setup, and do not know how it works. I guess you need to use a non-pure-sine wave (modified square wave) and set the dip switches per the chart.
I was going to use a UPS, and shut it off myself, but the UPS blew it's brains out and I got a refund. It was pure sine wave anyway so it would not work (I guess). I have a big inverter (sine wave), a 12V battery, and a charger. I probably have over an hour of run time or more if I am there to shut the room blower off. If you figure this out, please let us know.

 

[johneh]

As I understand it, the battery backup, no matter what make, just supplies power
to whatever it is hooked to when there is a power outage. It does not shut the appliance down.
You still have to turn the appliance off manually. Some units are designed to keep the appliance running for
some time until the battery is run down

 

[NS P-68]

If it is a modified sine wave it will pulse the combustion fan only every couple of seconds to keep the smoke from building up. I have the APC model spec'd by Harman and it it operates as described in the manual.
Curtissk I suspect you may have a pure sine wave unit and the stove doesn't recognize it. Or you need to change your dipswitch setting as per the chart posted by Whitenuckler.

 

[Curtissk]

If it is a modified sine wave it will pulse the combustion fan only every couple of seconds to keep the smoke from building up. I have the APC model spec'd by Harman and it it operates as described in the manual.
Curtissk I suspect you may have a pure sine wave unit and the stove doesn't recognize it. Or you need to change your dipswitch setting as per the chart posted by Whitenuckler.

NS P-68, thank you! I don't think my ups is pure sine wave, but I will confirm that. I'm starting to think that my control panel is original to the stove (2006) model. And I think the graceful shutdown may only be possible on a 2010 or newer?

 

[NS P-68]

That is quite possible. However if your circuit board has ever been replaced you may be in luck.
You would need to check the model # and revision on your board and set dipswitch 4 accordingly.

 

[Curtissk]

If it is a modified sine wave it will pulse the combustion fan only every couple of seconds to keep the smoke from building up. I have the APC model spec'd by Harman and it it operates as described in the manual.
Curtissk I suspect you may have a pure sine wave unit and the stove doesn't recognize it. Or you need to change your dipswitch setting as per the chart posted by Whitenuckler.

 

[NS P-68]

So only units after 2010...
I actually thought it was later than this.
So that's most likely your issue.

 

[bogieb]

Bogieb & whitenuckler,
I purchased a tripplite internet 750U. Plugged the tripplite in and allowed the battery to charge for 24 hours. Then, with my p68 running, I killed the power to the tripplite. Tripplite automatically kept the stove operating for 5 or ten minutes, then the tripplite killed the power completely to the stove. Unfortunately, I had smoke leaking out of my stove. I was hoping that the tripplite would shutdown the stove gracefully, but that didn't happen.
I then purchased a different UPS. An APC 850 VA. I got the same results with it. Any suggestions or ideas regarding why they aren't shutting down the stove gracefully would be greatly appreciated

That Tripplite is simulated sine wave when on battery power

The APC may be pure sine wave (according to AI, it depends on the actual submodel). That is why I specified the APC BE850G2 - it is modified sine wave.

So, either you have a pre-2010 board, or the dip switches are not set for this to work.

 

[mellow]

It sounds like you only did the chimney vent straight to outside, no vertical pipe for natural draft incase of a power outage, is that correct?

 

[mellow]

If you are looking for puresine in the APC line you want the PRO models.

This is from my pellet stove, yours may be different:

Shutdown time: 7 minutes
Wattage used during shutdown: 70 watts
Total wattage used: 8.2Wh

A 750 unit should be more than enough to cover the shutdown process.

I would however recommend going up in size since it will be running before you can manually shutdown the stove.

https://www.amazon.com/apc-sinewave-battery-protector-br1350ms/dp/B0779QFRRT?th=1