Inside the Robur GHAP

Unknown

or,,,"The Heat is Working Sweet!"

(oops, that's Robur GAHP)

The pump sits on rubber feet and is connected by flexible hose. Can be lifted out and placed on the ground to work on it. Two wide cogged belts and drive pulleys need to be changed every 3 years. It is hydraulically driven and the oil needs to be changed after the first year and every 3 years after that. hydraulic pump pushes a teflon wafer that pushes on the refrigerant side water. The wafer is beefed up in regards to the one in the old Servel/Arkla units and they lowered the rpm and I THINK shortened the stroke on the pump so it doesn't flex as much as it used to. They claim it will easily last 30 years. They also upgraded from the old Chrysler power steering pump Servel used.

Control Panel is a bit of a rats nest and I have issues with the size of the terminals they expect you to connect to. I needed to put 2 wires on L terminal, even though it only requires #14 we ran #12 because it was a far run. I needed to put another #14 on the same terminal with the #12. It would only accept 2-#14. I had to splice a ground as well. So if you notice those red wires with the yellow wire nuts, that will explain that.

The big board is refered to as the S60. It controls and monitors operation. It has a knob that you turn to scroll and press to enter and will take you through everything including real time readings on every function they monitor. The gray coax bundle to the right is the leads to the various thermistors. That's how many parameters they monitor. Generator temp, pump rpm etc. The three numbers you see are constantly displayed in a rotating cycle, they are hydro side temps. 78.1 is water in, 91.4 is water out and 13.3 is differential. The board also shuts down the unit if potentially damaging parameters are exceeded. The old units would burn out generators because they weren't serviced regularly. VERY expensive repair, think welder. Robur has done it's best to make sure that if they don't service their unit, it won't eat itself. The boards have been very reliable. There is an "eye" in the outermost panel as well. So you can always see temps without pulling the panel. You can make adjustments through the hole you see next to the eye. There's a little plastic "tool" for doing this.

I ran the primary loop in 1 1/4" and installed a Grundfoss UPS26-99FC without the check and on low speed, the unit is giving me 18* differential over ~14 gpm when it is operating at full capacity.

The way it works is as long as there is a call for heat and water setpoint has not been satisfied for 10 minutes it will continue to run the two pumps and the fan. As water temp dips below lower setpoint it brings on the gas and boosts the water temp until it reaches upper setpoint. Then the gas shuts off. However the two pumps and fan continue to run. They continue to remove heat from the air and introduce it to the system to be added to the water. So once the system temp has stabilized and the structure is warm it is quite possible, on a warmish day, for it to fire gas once every 20-30 minutes for only about 5 minutes and still maintain setpoint.

If the water temp stays satisfied for 10 minutes and one second, it shuts the pumps off and waits for the lower setpoint to be exceeded. The ten minute cycle is known as "spin down". Once lower setpoint is exceeded and there is a new call for heat the unit goes into a 7 minute "spin up" cycle, again only running pumps and fan. If, at the end of 7 minutes, upper setpoint is not satisfied, the unit will fire gas, if it is the unit will go into spindown again. I HAVE seen these units create as much as 10* differential in spinup on a 50* day. So the potential is there for it to come on, run pumps and fan only and satisfy upper setpoint without ever firing gas. My unit yesterday, two pumps and fan running, was drawing 6.5 amps.

Cool huh? ;)

tim smith

MPF, Thanks for posting the Pics and operation description

I have worked on the old Arkla's in the past and they were say, left with some desire. Pretty cool. Tim

Unknown

YW

I have a few Servel's under my belt. I never did run into refrigeration side problems. Never had a disc crack or generator burnout. Or leak. Sounds like I was lucky. These new ones are a cut above. They did a very nice conscientious redesign on them. They do have a few minor quirks but they have been very solid so far. Fortunately, I can weld. So the first time it happens I'll be setting myself up with a MIG. Other than the welding aspect, they really aren't all that different from conventional A'C units. The reversing valve is a spider and a half. LOL. Electrically operated by solenoid, not gas.

Unknown

Went there today.

Floor temp in both buildings 65*, air temp 60* from floor to ceiling 12' up, no more than .5* difference top to bottom. Water outlet setpoint 95* diff 7*. Seemed pretty comfortable to me, a little cool maybe but you could feel a small amount of extra heat from the floor(s). Outdoor temp when I got there 55* but windy. The coil on the unit was frosted because the low temp water outlet reqirements and the high ODT were enough to keep it from initiating a defrost. Called the factory and was told that even though it rubs me the wrong way it's normal under certain condtions. It was perfectly happy sucking heat out of it's frozen coil. Jacked the outlet temp to 100* and the diff to 10* and it went right into a defrost. The 5* additional water temp could be felt on the skin a couple hours later. 60* was actually before I left. When I got there it was 57* so it picked up the extra 3* over the 3 hours I was there. The gas co official came out and I gave him the grand tour. His final words were, "Well,,,I'm impressed."

Paul Fredricks_9

Is this the studio? So when is the tour?

Unknown

Yup,

Tour? It weighs 936 lbs, if I'm touring with it your helping me lug the thing.

I do know of a day long progressive rock festival at Toad's Sunday july 19th though. Doors open at 12:30 music starts at 1:00. Tickets go on sale soon at Toad's website. Seeing how's I'm the promoter, I should be there all day.

Unknown

If you feel like seeing the system,,,

and the place let me know, I'll show you around. You must record while you bask in the comfort that is radiant heat. LOL...