Rheem PRO+G29-60N RH70 (aka XR90) - UPS?

[MFred]

Hello,

Long time reader of the forum - have learnt a ton from all of the information shared here over the years. First time poster.

I got this Rheem Professional Classic Plus Induced Draft 29 gallon, 60,000 BTU water heater installed by a professional last week. I have been researching this for a couple of months and was drawn by the combination of FHR, recovery rate and energy efficiency of this heater. This replaced a 14 year old Bradford White 40 gallon.

My one concern with this (and most of the newer) water heater is their dependence on electricity. I live in the Portland, Oregon area where power failures are rare, but, do happen during the winter (ironically, when we need the hot water most!). I have read a few articles/posts online that it's OK to use a UPS between the water heater and the wall outlet. I have a brand new 1350VA UPS (modified sine wave) and am wondering if any of you have any thoughts or recommendations. Here are a few additional data points:

1. The installer did not recommend using a UPS because he felt that the blower motor wouldn't work (or work well) with the UPS. He wasn't sure if the modified sine wave would damage the motor or anything else in the water heater.

2. You guys probably know every bit that uses electricity in this heater - is there anything that can get fried by a modified sine wave UPS?

3. If a modified sine wave UPS is risky, how about a pure sine wave UPS? (such as
https://www.cyberpowersystems.com/products/ups/pfc-sinewave/cp1500pfclcd

4. I contacted Rheem Tech Support with these questions using their online "Contact Us" page, but, haven't heard back.

5. Will a UPS damage components in the water heater? Will using one impact the warranty? (this is probably a question for Rheem, but, since they didn't answer, I'm hoping you guys can speak from experience ).

I value your expert opinions and any recommendations you can share will be appreciated greatly. I'm sure I'm not the first person with this concern about the newer water heaters, but, am hard pressed to find answers online.

Thanks in anticipation!
MFred.

 

[Jadnashua]

Some things do not like modified sine-waves, but a pure sinewave unit should work. But, not sure what the power draw on the thing is, the battery(s) might not last very long when trying to power the WH. Most UPSs are used to provide a bridge to allow you to safely shut off more critical items so that they aren't damaged or to clean up the power and protect from momentary voltage drops or outages, not run them for long periods of time.

 

[Sponsor]

 

[MFred]

Thanks Jim. My understanding is that for these new gas water heaters, the electricity use (watts per hour) is minimal - which is why it is not even considered/listed as energy consumed by the water heater. The manual states that the water heater has a maximum draw of 5A - which, I believe, is the initial surge current to start the blower motor. The blower motor is itself, pretty tiny, but, I've been unable to find its power rating.

 

[Master Plumber Mark]

why did you go with only a 29 gallon heater?? \
that seems silly considering a 50 gallon unit cost you about the same amount...
are you still getting enough hot water with this unit>>>??

 

[MFred]

This was based on everything I've read about it and the installer's recommendation. It has a 60,000 BTU and so, has a much higher FHR and recovery than most 40 and 50 gallon gas water heaters. I'm sure you're familiar with this heater, but, if not, here are the specs - http://www.rheem.com/product/reside...rofessional-classic-plus-series-induced-draft

I've only had it for a couple of days, but, so far, it does seem to heat water a lot faster than my previous 40 gallon, 40,000BTU Bradford White. As for adequacy, I'll know when in a couple of weeks when my family gets back from vacation (but, the installer said that this was a very worthy 50-gallon alternative).

 

[MFred]

Here's the blower's label. Looks like a 1.05A motor. A 1500VA UPS should run it for a few hours. Also, the blower only runs when the burners are on. The 60,000 BTU burner heats the tank pretty quickly (haven't timed it, but, it's certainly fast).

 

[Reach4]

Here's the blower's label. Looks like a 1.05A motor. A 1500VA UPS should run it for a few hours.

There is a good chance that you have a friend with such a UPS that would lend it to you for a test. Not one that would last for hours with the standard battery, however.

 

[MFred]

Yeah, I have spare UPSs at home (both modified Sine Wave and pure Sine Wave) and can try it out. However, before I do so, I wanted to check with the experts on this site to make sure it wasn't a "STOP!!!! Plug in a UPS and kiss your new water heater goodbye" situation

 

[DonL]

Yeah, I have spare UPSs at home (both modified Sine Wave and pure Sine Wave) and can try it out. However, before I do so, I wanted to check with the experts on this site to make sure it wasn't a "STOP!!!! Plug in a UPS and kiss your new water heater goodbye" situation

The best thing to do is hook up your UPS, When the heater fires up, Note the blower speed, Then unplug it from the outlet, so that it is running on battery, and listen to see if the blower speed changes.

If the blower motor does not like the modified sine wave you will hear it and the blower speed slows down.

If the speed stays the same, It should be fine. If there is a big difference in speed and it Hums loud, I would not use it.

A short test should not hurt anything.

One thing to note about a UPS, Is that it will always be using battery power during a power fail, Even if nothing connected to its output is using power. It is still making 120VAC.

Good Luck.

 

[MFred]

Thanks Don. I'll try it and report back in a few days.

 

[Master Plumber Mark]

Isnt there a honeywell circuit board in the thermosat control box
I wonder if their could be an issue with it if you were to porceed with
this idea??