Heat pump water heater

woodgeek said:

My news from the HPWH front.

I am past the fifth anniversary of putting mine in and scrapping my 'old unfaithful, tried to kill my kids' oil fired boiler. Only problem I had years ago was I had the AO Smith unit 'brick' when its controller board died (a couple months after an epic power surge), and I replaced it myself after the maker fedexed me a replacement board for free.

I have found that the intake air filter (looks like the screens on window ACs) never gets dirty. Thinking that it might restrict the airflow (the AOSmith unit has a bigger fan than most) I took it off and found that the unit got much quieter...can't hear the low 'warp engine' thrum in my living space when its running. Happy.

But at the same time my dehumidifier started working a lot harder (both are in a power ventilated, semi-conditioned attached garage). I figure that at much higher airflow, the air coil is running a lot closer to the air temp, and perhaps above the dew temp...limiting dehumidification. So I put the filter back on.

However, I plan to run without the filter in the cold weather (it gets down to the low 50s in there in Jan-Feb) and should get a little boost to COP and recovery, in addition to getting quieter warp engines.

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That is a short term fix unless you have the ability to clean the evap coil yourself. I cleaned mine this spring and it was very easy to do.

I have access to the coil...and it and the screen/filter both look like new (clean) after 5 years.

Seasoned Oak said:

The cool air coming from the HPWH is welcome in the summer and in winter that area is usually around 80 degrees with the stoker going or 90 degrees if the wood stove is going so no need to vent the cool air.

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If you've got a coal boiler, why not use that for hot water in winter? I turn my hpwh off in the winter.
edit: coal not oil

velvetfoot said:

If you've got an oil boiler, why not use that for hot water in winter? I turn my hpwh off in the winter.

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Woodgeek and I had a little debate over this, sometime back. It likely depends on your climate and building properties, but he argued that your sub-grade walls (around here they hold 53F below 4 feet) are still supplying enough heat to a typical uninsulated block (for our region) basement utility room, that the HPWH will be more efficient. My thinking was that I have this hot boiler, anyway, and I might as well just switch to that for DHW. In my case, I also have a basement rec. room adjacent to the boiler room, so the excess heat off the boiler isn't exactly wasted (it just cuts down on how much the baseboard runs down there).

I'm sad to report I still haven't installed an indirect HPWH (mostly because I haven't found one that fits my needs, yet) on my BoilerMate, to test and settle this debate. If anyone has a link to an indirect HPWH with 3/4" ports, which does not rely on a restrictive coaxial dip tube to connect into the boilermate tank, it would put me a step closer.

Ashful said:

Woodgeek and I had a little debate over this, sometime back. It likely depends on your climate and building properties, but he argued that your sub-grade walls (around here they hold 53F below 4 feet) are still supplying enough heat to a typical uninsulated block (for our region) basement utility room, that the HPWH will be more efficient. My thinking was that I have this hot boiler, anyway, and I might as well just switch to that for DHW. In my case, I also have a basement rec. room adjacent to the boiler room, so the excess heat off the boiler isn't exactly wasted (it just cuts down on how much the baseboard runs down there).

I'm sad to report I still haven't installed an indirect HPWH (mostly because I haven't found one that fits my needs, yet) on my BoilerMate, to test and settle this debate. If anyone has a link to an indirect HPWH with 3/4" ports, which does not rely on a restrictive coaxial dip tube to connect into the boilermate tank, it would put me a step closer.

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I have a previous offering from tominmaine, a Nyletherm, for several years now, and it's tied into an electric water heater. Outlet from NT goes to WH drain, inlet from NT comes from tee connection on WH cold water pipe. I don't know about 3/4" though. This manner of connection does not interfere with flow through the water heater, far as I know. It's a parallel operation thing.

It makes a fair amount of noise when running, but I don't live in the basement.

Tom is offering some other units for $300:
https://www.heatingstuffllc.com/store/?model_number=WH-6BX-1

I don't think the boilermate is insulated as well as a typical electric water heater though.

velvetfoot said:

If you've got a coal boiler, why not use that for hot water in winter? I turn my hpwh off in the winter.
edit: coal not oil

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I tried that but my HPWH started to leak. I find this a common occurrence as my regular electric WH in the past did not last more than 2 yrs if i left it go cold for months at a time. So now i never turn my WH off. Even if i use the boiler for endless HW. Very small leaks will evaporate quickly on a hot WH but on a cold one it will just rust to pieces. The HPWH may even be more cost effecient than the coal boiler anyway.

Any kind of Electric WH seem to last so much longer if you never turn em off .

velvetfoot said:

I have a previous offering from tominmaine, a Nyletherm, for several years now, and it's tied into an electric water heater. Outlet from NT goes to WH drain, inlet from NT comes from tee connection on WH cold water pipe. I don't know about 3/4" though. This manner of connection does not interfere with flow through the water heater, far as I know. It's a parallel operation thing.

It makes a fair amount of noise when running, but I don't live in the basement.

Tom is offering some other units for $300:
https://www.heatingstuffllc.com/store/?model_number=WH-6BX-1

I don't think the boilermate is insulated as well as a typical electric water heater though.

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Many of these units are designed as add-ons to electric water heaters, only, as they rely on the voltage supplied from the thermostat on the lower coil of the electric water heater.

Seasoned Oak said:

Any kind of Electric WH seem to last so much longer if you never turn em off .

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I didn't know that.

Had an f11 or f13 code on my geospring the other day, scared me till i got closer and saw clean filter.
Had my floors sanded in aug, thats gotta be the culprit. Never had much dust anytime ive looked.

I'm going into my 4th year with my GeoSpring. I heard this past summer GE terminated the GeoSpring heater due to low sales. That is unfortunate and hope mine continues to operate 15 more years trouble free.
Regarding the dehumidifying, I have mine drain into a 5 gal pail. I generally dump 4 gal every week in the summer. In the past Ive heated my house with a woodstove in the basement so I ran the HP mode year round. Even though it only drops the basement temp 1-2 degrees on average it feels like a lot more because of the humidity. I like mine a lot and have had no issues. I see Lowes only offers the AO Smith HPWH now...

Bought mine 3/15 from Lowes, Whirlpool version, I'd have to look at the manual to see who manufactured it. I use the heat pump only mode as that provides adequate hot water for the two of us. I removed a propane fired unit as just the standing pilot was costing as much as the electricity we now use to run the HPWH. Extended warranty was the same price as a regular water heater, cheap coverage out to 9 years or so. I installed in the same room as the wood furnace so plenty of excess heat in the winter for the heat pump to do its thing. I will definitely buy another unless something better comes along.

velvetfoot said:

If you've got a coal boiler, why not use that for hot water in winter? I turn my hpwh off in the winter.
edit: coal not oil

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Another reason is the HPWH only cost about $10 a month to operate. My coal boiler cost $30 a month minimum just in idle mode to stay lit, before any load is put on it. The coal boiler shines on cold days when gas or oil heat never seems to turn off . But late spring ,summer and early fall. it just idles too much to be practical to run. Especially just for hot water. Yes id buy this HPWH all over again ,cant go wrong with an appliance that pays for itself with electric savings.

I'm a little over 4 years on mine. It has been running pretty much nonstop in heat pump only mode. The only issues I had were the 2 electric elements disintegrated I believe from never actually using them. When it did a self check when I restarted it once it threw a code for bad elements. I pulled them out and they were shot. GE sent 2 new ones for free. The replacement ones were like twice the thickness.

The only other issue was I kept getting a filter warning though it was running fine and the filter was clean. The tech said they had a upgraded fan kit that greatly increased the airflow across the condenser. The fan was way more powerful then the original one. Mine has a build date of 03/2013.

My original cost was around $200 with local utility incentive and I caught it on sale.

CT residents can still get them for like half the cost as there is a $600 rebate. If you put in a CT zip code at lowes the AO Smith comes up as $799 with the instant $400 utility rebate offered on local purchase. Then there is an additional $200 one for CT residents. Anyone in surrounding states could drive here and get it $400 cheaper instantly. I tipped a member off from Long Island last year I believe and he took the ferry over and saved like $600 vs buying it on Long Island.

Brian26 said:

I tipped a member off from Long Island last year I believe and he took the ferry over and saved like $600 vs buying it on Long Island.

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That was me! Thanks again!
Running good so far, still would like to do the yearly crack the bottom valve to let sediment out.
My nephew has an older geospring, threw a code and stop working. The company that took over sent him a bunch of stuff, ended up being the control board.
Good to see we still have good service to support any issues that may arise.

Stand alone HPWH can be rewired to work with non-electric tanks. www.heatingstuffllc.com
has the Etek, which is what the Nyletherm was a copy of.
We sold out of the Nyletherms although we have some controls left.
The Etek is $365 delivered in the Continental US. If you need to rewire, I will send you the wiring diagram and the relay needed to do this.
You will have to add an aqustat to operate the heat pump by temperature.

tom in maine said:

Stand alone HPWH can be rewired to work with non-electric tanks. www.heatingstuffllc.com
has the Etek, which is what the Nyletherm was a copy of.
We sold out of the Nyletherms although we have some controls left.
The Etek is $365 delivered in the Continental US. If you need to rewire, I will send you the wiring diagram and the relay needed to do this.
You will have to add an aqustat to operate the heat pump by temperature.

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Will the Etek work with marathon unit?

Once rewired, yes.