Heat Pump Water Heater

[greenjp]

Digging this back up since I have a bit of a functional update. Actually, more of a piece of advice for anyone who has bought a Rheem Proterra.

Go ahead and spend the $20 and order a new set of 4 thermistors.

https://parts.rheem.com/en/product/RPD-AP18087

Oooh this is great and timely info. I installed one of these at the mother in law's a few years ago, works great but lately the compressor has been shutting off. Threw some low suction error or something (don't really the number literally just deleted it earlier today), shutting the whole thing down for a bit seems to reset everything, but it keeps recurring. I'm not local but should be able to repair over Christmas if this is in fact the issue.

jeff

 

[ctechbob]

Oooh this is great and timely info. I installed one of these at the mother in law's a few years ago, works great but lately the compressor has been shutting off. Threw some low suction error or something (don't really the number literally just deleted it earlier today), shutting the whole thing down for a bit seems to reset everything, but it keeps recurring. I'm not local but should be able to repair over Christmas if this is in fact the issue.

jeff

99% chance that is the case. By all accounts the actual compressor assembly is solid, it's just let down by the thermistors.

When mine went out I was shocked at how much power the elements use. I know that's what I used to use to heat my water, but when you use about 3kw on an average summer day, and all of a sudden you see the usage shoot up to 12+kw it is a little bit of a shock to the system and feels super wasteful.

 

[ctechbob]

I just realized I accidentally deleted the manual from my Google Drive.

 

[greenjp]

Ok so it happened again overnight per the app. Getting error A006 Suction Temperature Too Low, along with a hardware alarm that the filter is clogged. I had them wash the filter off so don’t believe that’s actually the problem. Consistent with the thermistor issue?

 

[ctechbob]

Ok so it happened again overnight per the app. Getting error A006 Suction Temperature Too Low, along with a hardware alarm that the filter is clogged. I had them wash the filter off so don’t believe that’s actually the problem. Consistent with the thermistor issue?

Most likely.

There is a key combination you can press to display the thermistor readings and cycle through them. One of them will be way out of whack.

A004/005/006 are all thermistor related.




This guy shows how to get into the thermistor check mode.

 

[ctechbob]

If you go into test mode you'll probably see that the 'ST' temp readout either isn't reading, or it is reading far too low. It should start to slightly climb up towards ambient when the compressor is running.

 

[ctechbob]

I debated adding to this post and starting another one. Apologies to those who get a little out of sorts by digging up an old post, but this will be valuable information for DIY people that own the Rheem Heat Pump Water Heaters.

As I posted above, the thermistors are a bit of a weak spot for these machines. It used to be that the Rheem thermistors were a few bucks a piece and you could replace all 4 of them for around $20.

Being a big company, they have discontinued the thermistors and now sell them as a 'kit' that includes new clamps that you don't need as you can easily reuse the old ones.

I'm not paying that, and you shouldn't either.

Digikey to the rescue.

Being that I've already replaced mine once, I saved the old thermistors, hacked off the connectors, solder, heat shrink, Bob's your uncle.

I did compare values of the new vs the 'old' ones. They match up perfectly. I had replaced all 4 of them the first time one went bad, so 3 of them were still good. That was what I compared the new Digikey ones to. Room temp, 160 deg, and 40 deg, all the readings were almost dead on, so I'm confident these will work when the time comes.