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A little more on the Robur GAHP

I watched the unit today while I was puttering around at the jobsite. ~55* ODT maybe a bit more, didn't get an actual but the thing is I watched it power up, chug along for a while, satisfy setpoint and shut back down without ever calling in gas. I saw it do this several times.

On another note: Things you don't mind hearing from your customer on the new radiant job. "This heat is AMAZING! You're not even aware of it being there! Well done!" ;)


  • clammy
    clammy Member Posts: 3,094

    Job well done mfp ,is it not great to finally get a atabot from a HO ,what i think is great is that they took some old technology and up dated every thing and endup with a product that gives the results it's suppose to in one neat package ,it will probalby be about 10 years before it's common place and of course american based companies would never think of it .I'm waiting for mitz or sanyo to do the same and blast carrier /trane with a interverter condenser unit/air handler unit. for central it serve the ameriican companies well for sleeping on ther job PEACE AND GOOD LUCK CLAMMY
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • yea,

    The best part is he's a REAL finicky one and to see him all giddy and happylike is very comforting. I made sure to point out the non gas operation part too. He was practically dancing a jig. lol...

    On a day like today he's heating 2 buildings ~3500 sq ft using only 6.5 amps intermittently. Gas usage was negligable. I think it fired once but not for long, the only reason I knew is becasue the chimney was a little warm. Other times I checked it it was ice cold.
  • Mark Custis
    Mark Custis Member Posts: 539
    The checks

    clearing is a plus.

    It is nice to do this, it is also nice to ne able to eat.
  • Very true,,,

    I'll give the guy one thing, he's been REAL good with the $.
  • JJ_4
    JJ_4 Member Posts: 146
    System Question

    MPF...You may have posted this before, but what type of system is this? Water/Air or Water/Water? If Water/Water...I guess it is ground source? Is there any backup boiler/chiller or is this standalone? I would be interested in a system diagram if you have one...I'm sure others would be too.

    Thanks, JJ
  • Air source to water (glycol mix)

    It's stand alone. The air source Robur is good down to -20*F ODT and our location is central CT so I give the customers the option of backup but given the rarity of -20* weather here and the fact that we, so far, use it to heat concrete, they have chosen not to include any backup. For this particular job I have the unit heating/cooling a buffer tank which in turn supplies 4 zones/pumps, so it's pretty straightforward as far as a diagram. Each building has one floor zone and one airhandler. I ran Ecoflex underground to the second building and located it's pumps on a manifold at the end of the Ecoflex. Here's some pics, sorry I don't have a diagram. There's an external pump under the black plastic in the Robur pics. It circulates solution through the unit and the buffer tank
  • clammy
    clammy Member Posts: 3,094
    few questions?

    MFP are you running glycol through the system side ?Does the out door unit come with a system pump(not the ammonia solution pump)and also what's the max temp excepted that the unit will produce in heating mode ,can it be used for DHW production,on another note have you tryed a boiler buddy over a standard buffer tank i have used 2 of them and found them to work well 30 and 80 gal models 4 tappings excellent for hydro seperation and air elimation . Also are you going to try to use the chilled water through the slab for radiant cooling ?I wonder what your thoughts on them are ,Thanks for posting on this system i think they will be for AC what mod cons are for heating peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,537

    That's an air to water heat pump?
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • Yes,

    There's glycol throughout, I didn't want to lose the extra efficiency by running it through a heat exchanger.

    The unit does not come with a primary pump because each application may present different head loss. It requires 13 gpm through the unit to function, there is a flow switch that will shut it down if proper flow is not maintained.

    The unit runs on 208/230 1 Phase and the control board has dry N.O. contacts that can either feed the pump directly (3 A or less) or you can call in a relay with them. I used a 208/230V Grundfos UPS26-99FC with the check valve removed and low speed turned out to be perfect. You set the flow by pressure diff across the unit. They want you to use a balancing valve on the pump discharge to do this but low speed worked just right so I had no need to restrict the flow. I had 14 ft / 14 gpm figured. Had to go with the Grundfos because Taco couldn't get me a similar pump in 230 for 6 weeks. The pump draws just about 1 amp, the unit running full out (fan and all) runs about 5.5 amps so total is ~ 6.5A. The unit controls the pump operation.

    It will produce up to 140*F for heat and 37.4*F for cool. They claim it can be used for DHW but to do that you need to run it at 140*, the problem is the lower you run your system water temp the higher you can get on the efficiency so it kind of defeats the "ultra" high efficiency aspect if you go making DHW with it. Plus, in the summer you'll be making chilled water with it so DHW presents another problem as far as that goes. This is my second install with it and I'm finding 120* system water seems to work the best. When you feed air handlers with it you size them for cooling. This gives you about 2.5 times the size coil you need for heat so even with 120* water being fed to them the air coming out will feel warm. Once you go below 120* the air starts to feel cool so that's where the biggest limitation lies on lowering water temp.

    I haven't heard of the boiler buddy but the 30 gal sounds interesting. The smallest heatflo tank I could get is the 45 gal you see in the picture. It took a lot of extra glycol because of the tank size so I'd LOVE to use something smaller next time (should there be a next time). Robur said all I needed was a 25 gal but I could not find one. That tank wasn't cheap either. It is stainless with a lifetime guarantee though. Got a link to boiler buddies?

    Yep, the plan is to feed chilled water to the slabs. I installed Unico high velocity air handlers to suck up the humidity because they're supposed to be superior for dehumidification. My control plan is to run the AH pumps on both stage 2 cooling and dehumidification from a Honeywell IAQ stat. Thought being if the humidity is high the AH will come in and if space temp drops too low the stat will shut off the pump(s) to the floors leaving the AH to run on dehumidify. The AHs are undersized by about 25%. I will start with 48* system water and see how it goes. I'm thinking that I should be able to tweak in a happy medium where I'm picking up something like 50/50 of the load between the floors and the AHs. The unit runs at ~ 14 SEER in cool so it is not as much of an "energy star" in cool but in heat mode it can greatly exceed 100% in terms of gas usage. As much as 150% on a mild day, given what I've seen of it's operation the last two days. Understand, it burns gas at 80% just like a conventional gas boiler BUT it draws heat from the air and combines it with heat produced by the gas flame, that's how it can exceed 100%. People have a hard time over why it can put out more than it takes in because they don't realize the extra heat is coming from the air. They also make a water source too, just FYI.

    All I need now is a HOT day ! C'mon summer! LOL...
  • Yes,

    They do make a water to water as well. Wells cost a lot of $ though which is why I go with the air to water. It's literally plug and play. You drop it, hook up gas, electricity and two lines for system water and away you go. read my reply to clammy for more details.
  • Speaking of hard times,

    I did the CT homeshow with it last two years. I had one guy come up to me all nasty like and say, "You can't get more out of it than you put in, it's all just smoke and mirrors!!" I said, "Yes sir, you're absolutely right, that's all it is." ;)
  • Is that a

    Robur gas fired heat pump?
  • yes,

    that's right. Another FYI, it weighs 936 lbs.

  • nice work "pioneering" here MPF. what ODT have you observed it operating under so far, personally?
  • This one,,,

    has been operating for about a month now so probably the coldest I've seen while I was there was 20* ish.

    I have two more that have been operating for 2.5 years now at another site and they have been trouble free. Last I knew they were heating 12,000 sq ft (including basement and 3 car garage)for ~ $700 in gas and ~$100 in electricity per month during the middle of winter but there are 11 zone pumps (5 floors / 6 AH) and two huge primary pumps. The units are 70 ft from the pump station (long story that involves stubborn homeowners) so the primary pumps draw like 5 amps each. Again, unable to get the right Tacos in 230 volts so I had to go with 110V on them. Didn't consider looking into Grundfos at the time unfortunately. Under avaerage conditions only one unit and one primary pump run at a time. There is a proprietary Digital control that runs them as a plant and among other things evens out run time between them. I am not cooling any floors with them. This current job is my first stab at it.
  • I was at

    the factory training school some years ago and remeber them telling us about a future heat pump, The Indiana plant closed a couple of years later and I stopped selling them. Are they made in Italy now and imported?
  • Yes,

    The Evansville people send the parts to Italy, they're assembled there and then they're distributed throughout Europe and now the US. They did 2 years in Europe first to field test them before they released them back into the US. I was the first in the US to install them. So really they're made of American parts and assembled in Italy. You can buy most of the stuff off the shelf here. They have recently released a modulating unit in Europe and expect to release it here within the next couple years. They claim 170% efficiency on those. If you're familiar with Willis Schroder, he's still the head support guy in Evansville bt he's getting up there in age and is talking about retiring. I've been there for training myself. Interesting place.
This discussion has been closed.