Bosch's new heat pumps

[mrg2333]

I just went to a promotional seminar on Bosch's new air cooled heat pumps, and it looks like a pretty unique product. Our supplier hasn't even got them in stock yet, so I've yet to see one run. They say the inverter will work with ANY TXV coil, and needs no sensor or communication of any type with the indoor equipment - it modulates solely off of the suction temp and pressure. Lots of other cool unique features, but at this point I'm just looking for anyone who has actually installed one to get their take.

[Juan Madera]

me too. Like the idea.

[madhat]

If it's anything like their clothes washers, it'll be a winner. I have a 14 year old Kenmore HE3t washer, but if you look at it closely, it's a Bosch made in Germany. A couple years ago my wife yanked the locked door open, and broke the safety latch. it wasn't available from anyone. Called Bosch USA, told the guy my problem, he laughed and ask if I got the part would I be able to repair it. He then got my info, I figured I'd never hear from them. A couple days later the safety latch arrived no charge!

[BaldLoonie]

From what I hear, it's Midea made in China so probably won't do like the wash machine

[mrg2333]

I can't remember who makes the cabinet, it might be Medea, but I do remember they said that it has a Mitsubishi inverter with a crazy number of real speeds to modulate from. I think they tried to get domestic manufacturers to make it, but they couldn't find anyone willing because it has too much potential to kill sales of their own modulating units.

Every other inverter driven unit I've installed is 100% proprietary compatibility only - indoor, outdoor and controls all must match or no go. The Bosch unit is compatible with anything, as long as it's a TXV coil. Single speed PSC fan - no problem. A/C only application has two wire low voltage connection, heat pump four. It doesn't communicate in any other way and it doesn't care where the fan speed is, all modulation is done based on suction temp and pressure.

The control board has minimal adjustments, the main one is what temp you want the suction to return at: 37f or 47f. It has a 3 digit trouble code reader, but you can only display the codes once and then they disappear. They said they didn't include memory because they wanted to keep the cost down of the unit, and from the preliminary number our supplier gave us, they did a good job of that.

It only comes in two sizes, 3 tons and 5 tons. The idea is that if you have a 2 ton application, just flip some dip switches and limit the capacity. What's really surprising is how cheap it is. I'm not going to start listing prices here, but when comparing it to any domestic unitary manufacturers modulating heat pumps, its no contest. I'm an American Standard dealer, and it was even cheaper than any of their two stage cooling only scroll condensers (in any size)

I'm not trying to sell these units (except maybe to my own customers) but I was just looking for someone who might have one of these systems running in the field. For all I know it may turn out to be the biggest piece of crap ever, but on paper it looks pretty freakin incredible. I bought the demo unit they had and am waiting on their coil to be delivered so I can get a matched system with an AHRI rating that will qualify for our local utility rebate. Would love to hear from anyone with more info on it.

[Michaels HVAC]

R.E. Michel is caring them. I have the tech number and will be calling with a slew of questions. Just saw the unit to day. 4/15/2017

[fimiki]

We just had our old 4-ton AC replaced with a Bosch BOVA 60 heatpump and BVA-48WN1-M18 air handler. As mentioned above, one of the curious things Bosch did is rather then making separate 2 and 4 ton units, the 3 and 5 ton units have a jumper cable that you can cut to limit the capacity.

When the installer put in the unit he called tech support and they said to hold off on cutting the jumper, leaving it as a 5-ton condenser unit and a 4-ton air handler. Could this create problems down the road? What are the consequences of having an over-sized condensing unit? Since the compressor is inverter driven (inverter driven rotary compressor from Mitsubishi, according to the product specs), does it matter?

Also, the product brochure states that "The system along with an appropriate thermostat can learn your preferences, and adjust the output capacity to match your ideal temperature levels". However the wiring connections for the thermostat doesn't seem to have any additional wires for modifying fan speed. The blower fan has 3 speeds that you can set with a manual switch, so I'm not sure how the capacity could possibly be adjusted by a thermostat.

All in all, it's an impressive and clever system. One feature that actually made it ideal for us is that the BOVA condensing unit is only 29x29 inches. As there was only six feet between the house and neighboring retaining wall most other condensing units essentially blocked access to the back yard gate. The Bosch was the only high SEER unit that fit.

[BNME8EZ]

Seems funny that near as I know they have yet to manufacture a WSHP that is inverter driven which I know they have WSHP but I didn't know they had air source anything.

[beenthere]

Should not be a problem. The outdoor unit monitors the vapor line pressure and temp, and throttles down as needed.

[JeepersKreepers]

Haven't seen these but agree with others...the Bosch appliances I have had are also the very best appliances I have had.

[Juan Madera]

I mentioned to the rep that this might be a good fit for zoning with air handlers. Two air handlers of less than 6 tons and use a LLS off the thermostat. Let outside unit run as a pump down. He said it should work, but was not approved (yet) The 5 ton will do 110% of rating apparently.... Or two 2 ton coils with the 3 ton unit... With some diversity of load the efficiency should be extraordinary.

[Core_d]

Củious how decreasing câpacity and nót fan speed could effect humidity removal?

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[fimiki]

Should not be a problem. The outdoor unit monitors the vapor line pressure and temp, and throttles down as needed.

That's good to hear and it makes sense given that such a feature is one of the selling points of an inverter-driven compressor. It makes you wonder what is the purpose of cutting the jumper cable to limit capacity in the first place.

Củious how decreasing câpacity and nót fan speed could effect humidity removal?

Could it be longer run times to remove more humidity?

The other selling point is that it's much quieter on average than other units. I've gone outside a couple of times just to make sure it's running alright, and it sits right below one of the bedroom windows.

[beenthere]

That's good to hear and it makes sense given that such a feature is one of the selling points of an inverter-driven compressor. It makes you wonder what is the purpose of cutting the jumper cable to limit capacity in the first place.

You set it for 1 of 2 different suction line temps. To match the load better.


Could it be longer run times to remove more humidity?

The other selling point is that it's much quieter on average than other units. I've gone outside a couple of times just to make sure it's running alright, and it sits right below one of the bedroom windows.

Remember to take a flash light with at night time to check it. So you can find it. LOL

[Core_d]

That's good to hear and it makes sense given that such a feature is one of the selling points of an inverter-driven compressor. It makes you wonder what is the purpose of cutting the jumper cable to limit capacity in the first place.

assuming duct work is correct for the size you limit the system to... it would be the only way to properly charge the system.

Could it be longer run times to remove more humidity?

how low in capacity can it go? Most are about 40% total. On say a low load rainy day i cant see a 2-2.5 unit with 2000cfm doing a very good job but, i could be wrong.

That brings another question how can you maintain a low suction pressure/temp with a constant cfm? Is the out door fan variable as well. Even with a txv capable of doing 1.5-5 tons im having a hard time imaging how the air flow would come into play. One thing is for sure with the proper charge it will never flood. I could imagine this compressor hunting quite a bit though.

Fixed quotes..
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[madhat]

I had an ECM Motor in a Lennox and it had multiple taps on it for Fan speeds and yes it would still ramp up and down on the humidity and the duct temperature in heating mode.

[Juan Madera]

Use a 2 stage 'stat, a SPDT relay and now you can have a two speed fan to go with the modulating outdoor unit. Just pick your speeds based on BTU needs......

[Greg Lykens]

I went to a "counter day" yesterday and liked what I heard. The unit seems to be very forgiving. It is an ideal unit for an older home that has some old "heating only" ductwork, which means it is sized to samll for AC. The unit modulates in 1% increments to get a 49 degree (what the rep said) suction line temp. So it truly modulates down to 25% capacity. My boy said why not just put in all 5 ton units since it will modulate down to 1.25 tons. He said they are working on that, but it would cost a 1000 dollars more, but concievably, it would work.

Sounds to good to be true.......

[beenthere]

I went to a "counter day" yesterday and liked what I heard. The unit seems to be very forgiving. It is an ideal unit for an older home that has some old "heating only" ductwork, which means it is sized to samll for AC. The unit modulates in 1% increments to get a 49 degree (what the rep said) suction line temp. So it truly modulates down to 25% capacity. My boy said why not just put in all 5 ton units since it will modulate down to 1.25 tons. He said they are working on that, but it would cost a 1000 dollars more, but concievably, it would work.

Sounds to good to be true.......

Would probably have oil return problems if it ran at 25% for an extended period of time.

[Greg Lykens]

Would probably have oil return problems if it ran at 25% for an extended period of time.

Brought up a good point. Called the rep. They have 5 ton condensors on 2 ton coils. Ran them for a year like that. No problems.

Bosch Boilers are good and reliable as stink. I think they are well thought out.

Reason they got into the market? It is because Geo is about dried up since ther isn't tax credit for Geo units anylonger and those will be going away in the US, he suspects.