I just got done building a new, single family home/home office/workshop a few weeks ago (I acted as Gen Contractor). I love our new digs, but HATE the problems I'm having heating system. You might say after lots of research, I designed the system and had a "contractor" install the mechanical components while I ran the radiant in slab/joist, properly insulated the slab/found walls/f. joists, etc. The sad part is, if things were properly installed on the generation side, I don't think the design is the problem. I tried to keep it as simple as I could for what I was doing so as not to confuse both myself and the installer (he mentioned toward the end of my project he was second to last in his HS class...I'm thinking the other guy probably committed suicide). Sad part is, he wasn't cheap by any means...I paid extra to get him as he has the same system set up at his house, which made me believe he knew what he was doing! The radiant flooring I designed/put in works great, but heat distribution isn't my problem as it worked great...generation is! I've included some pictures of my problems: http://pa-softball.com/junk/geo/Thumbnails.html
My design:
I have a 5 ton Climatemaster Tranquility 27 split for my cooling (forced air) and supplemental heating. I have a 5 ton Tranquility 27 split w/ heat exchanger for radiant heating. Radiant is designed to be my primary heating source down to about 10-15 degrees. Both units have desuperheaters that dump heated water into a 160 gal buffer tank. The radiant unit solely heats water in the buffer tank. Each zone has it's own pump/thermostat/manifold and "talks" to a switching relay when it has a call for heat. The radiant unit/buffer tank "talks" to an outdoor temperature reset and turns the unit on when the buffer tank temp drops below the reset temp. My thermostats for the radiant "talk" to a switching relay...so there is no direct path between my thermostats and geo unit to tell it when to switch gears (stage 1 to Stage 2)...since I have a buffer tank, the plan was to always run it in stage 2. Rather than bring another tank into the mix, my DHW is preheated via a 180' soft copper coil in my buffer tank, then goes to a Elec HWH. I had a manual J done and my house, on the coldest day, would take 8
tons to heat every square inch (basement included as I put radiant everywhere). I have a 8 ton horizontal, closed-loop field that comes into my mechanical room in a 2" sch 40 PVC, then a 1" supply/return goes to each pump pack for the units. I only put 8 tons in as the second unit should never get out of Stage 1 for supplemental heating, which would be running on roughly 3 tons of unit (60% of my 5 tons, give or take)
My problems are as follows:
- It appears that my contractor has both units set up currently to only run in stage 1. My forced air unit is always right around 15 amps on each leg (220V). I'm not a electrican, but am pretty such you draw 110V off each leg, so I'm only getting 15 amps of 220V, or roughly 3300W. I'm thinking a 5 ton in second stage should be closer to double that, about 6000 Watts (which is what the owner's manual seems to suggest as well - ~25.5 amps @ 220V). The 15 amps jives with the amount of heat I feel is produced. I estimate my average actual heat loss on a normal day (20-25 deg) to be about 7 BTU/sq foot (roughly 28K for the house), which is roughly 3/5 the capacity of the system, which is what I believe it to be running on (stage 1). 3300W x roughly 10 BTU's per Watt (300% eff.) = 33,000 BTU's. The radiant unit, when it worked, seemed to also be producing about the same amount of BTU's based on the deltas and flow of my 2 main manifolds (17 loops-6gpm total @ 10 deg Delta) = roughly 30K BTU's. I would love to be able to get my units running in 2nd stage but his wiring inside the units is suspect. First, he clipped the end of the second stage jumper off and wire nutted it directly to the "Grey" stat wire...that seems legit since "Grey" is in the "Y2" position on my stats, but the Y2 jumper was never connected to the circuit board. I'm of the impression the blue, Y2 jumper is to be on the circuit board, so I just unconnected them and placed it on the board where I'm reasonably sure it belongs. If I'm not mistaken, I also need a jumper between the Y2 on the board, and the Y1 to make it live? Does this mean I run a connecting wire between the 2 blue stage 1/stage 2 wires?
- My radiant unit recently burnt up a pump that he has between the unit and my buffer tank. The tank is atmospheric pressure (not pressurized), so to me it seemed critical to mount the pumps below the tank in order to not lose prime. Well, he didn't do that, stating an "Air Eliminator" would keep out the air. Needless to say, 2 burnt up pumps later he still hasn't come back to fix the problem or re-mount the pump. I'm thinking that when the pump burnt up this time it potentially caused damage to the unit as the unit appears to be on lockout. I assume this based on the fact that when I went down the one day it got cold in the house the pump was burnt up hot, and the area around it looks as though it sustained some serious heat, even melting some of the pipe insulation in the area, baking thermostat wires, and some of the flux seems to have ran down the copper. Instead of mounting a temp bulb inside the buffer tank, he has a sensor on the copper inside the heat exchanger. In order to get an accurate temperature reading, I have to run the pump on 24/7. Needless to say, this seems like a lot of wasted energy as it's a 26-99 (220V) pump (~$25/month!), which seems overkill itself (I was thinking a little 15-58 Grundfos on 110V would do the trick as there should be virtually no head - water is being lifted mere inches and traveling 5-10 feet - which is what I remounted/primed to try and get it back up and running). He stated the need for a 220V pump as the unit runs on 220V...I asked him why it couldn't just run off 1 leg? I had a 15-58 around, and replaced it to try and get some heat, but can't get the unit on as I believe it to be in lockout. When I turned the breaker on after mounting the pump the unit wouldn't do anything.
- I had my return lines frozen solid the other day when I went to my basement to see why I had no heat. Against my best wishes, there is no flow check (except on the pump, which I don't believe to be water tight) to prevent water from taking the path of least resistance. Instead of using my loop field, it's simply circulating water from one unit through the other. I turned the ball valves off on the radiant side (since I couldn't get it to work anyway) between the 1" supply and the pump pack to get it to push through the loop field. This works for now, but will not allow for the operation of both units in the long run. Any ideas how this can be rectified?
- My electric bill last month was $650! I was thinking that it would be closer to $400 for the geo, pumps/air handler included. Last month was cold, but if my normal bill is less than $100, that's over $550 for heat. At $0.11/KWH, that's 5000 KWH's, or roughly 50 Million BTU's at roughly a COP of 3...easily obtainable according to Climatemaster charts and around most closed loop applications in this area. 50 Million btu's would be a BTU loss of 67,000/hr or 16.8 a sq'...seems a little high to me. I'm thinking it could have been the problem with not using the loop field, therefore I was essentially using the compressor as electric resistance heat while only pulling a tiny bit of heat from the loop field (whatever resistance the check valves in the pumps could force through the loop field...COP of 1. That, and when both units were on
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- There are a couple other problems that need fixed (he has 4 of my 7 manifolds mounted above the water line of the tank), but I think I have the solution to those. Several of those manifolds lose prime and backdrain down into the tank...pump runs dry, pump burns up. I think remounting the pumps below the water line, or putting an expansion tank above the highest radiant loop, would do the trick.
Thanks in advance for any help anyone can offer. I'm looking to get this all behind me and be warm for a change (68-70 would be great!)
. It's been about 57-60 in the house since the radiant unit went down. I've attached some pictures for your humor/understanding of whats going on, and to give you an idea how not to do things. That being said, the distribution of the radiant heat seemingly worked great when the unit would run.