alfredeneuman
Well-known member
...and it is required for all new residences built after Jan 1, 2020
Last edited:
Split Service to Furnace?
- Thread starter dziskovs
- Start date
wyliesdiesels
Well-known member
yup...and it is required for all new residences built after Jan 1, 2020
So have an update on Geothermal electric usage... long story short, changing the setting didn't really address the issue. I've been tracking daily meter readings relative to temperature, and have used 1400 kWh so far this month (average of 73.7 kWh/ day). Daily high was 160 kWh in a 24 hour period between readings on the coldest day/ night combo over the last 3 weeks.
Temp dropped below 30F this last weekend, and I can see that the unit stages from Stage 1 to Stage 2 to Resistive Heat below 30F. It is using geo and resistive heat when below 30F instead of just resistive heat, so I guess they fixed a small issue.
Both today and yesterday, I've been manually tracking data while WFH, and noticed a few different trends.
1.) HVAC stages every 3 minutes until Leaving Air temp (LAT) hits 88 deg F. (Confirmed the 88 deg F in the arzel zone controller settings).
- So every time unit has kicked on since Heat was enabled in October, it has run 3 min in Stage 1-> If LAT temp not met/ Temp request not met then stages up to stage 2, runs 3 minutes, and if it doesn't hit 88 LAT and satisfy temp request, then it kicks on Resistive heat (when below 30 deg F outside.)
*I think this is the majority of the problem
2.) Unit seems to cycle on and off frequently. I tracked it yesterday for an hour, and got the chart below... If it was kicking up to stage 2 heat or resistive heat (not shown, but implied) then that makes sense why the unit only runs for 5-8 minutes every time before the zone is satisified, and then kicks off for a short time. Thermostats are set to 5 Cycles per hour (default settings, only changeable in technician access), which matches what graph below shows. I'm assuming changing CPH to 2 or 3 will make the unit run less often, but my gut tells me based on the LAT stage up settings, it will still only run for 6-10 minutes each time since it will get to stage 2 heat after 3 minutes and be satisfied.
*I think this is compounding problem above...
Have HVAC company coming back out Thursday morning, so hoping they will get things setup correctly this time. I've been shoving data at them hoping they will come and make this right (I've essentially spoon fed them the root cause while spending my time taking data and telling them what is happening). The root of all of this seems to be zone controller setup, and not even the geo operation, which I guess is more frustrating since any HVAC company should know how to setup a zone controller. This one just happens to be running a geo unit vs. fossil fuel unit.
I'll report back after a week or so hopefully with lower daily kWh usage. If its fixed, then I need to figure out if I go after them for high bills the last 4 months since they did a crummy job setting it up in the first place.
Fav Onefour
Well-known member
Are you saying it runs resistive heat and geo at the same time? I may be misreading because you also say stage 1, to stage 2, to resistive heat.
I'm in a colder area but we don't typically run resistive heat unless geo can't satisfy the stat. It is set up as it's own stage and runs independent of the geo.
The run times with stages are awful short.
Geo systems should run more efficiently with longer run times because starting compressors takes power.
I had a geo setup at the house that was done in '03 initially. It was sized to use Geo down to zero F range and switch to backup if needed at that point. Integrated multi stage and combined zone controllers were not well developed at the time. It also had a two stage piston compressor. It was pretty clear when the ****** switched stages and it happened often. I struggled with short cycle times too. The setup lost efficiency with the short cycle times. Temps around zero made the system run like a city bus on a short stop route. Dang system was driving me nuts.
The zone controller was "tied" to another system controller and it just didn't work. I tried outdoor temp sensors as variable shutoff points between heat stages. I was able to extend run times a little because the system didn't keep swapping stages right at the edge of capacity. I was able to stay Geo heat with lower outdoor temps. It still went into backup heat more than I liked.
In 2017, I was working out of town and wife called. Heat wasn't working. I told her to get a tech in to get it going. Main board was kaput and the guy wondered how long we wanted to keep playing with this old controller setup.
Long story but the end result was replacing the whole controller setup with a stand alone stage and zone combined setup. Got rid of outdoor temp shutoff sensors. Swapped in a scroll ramp up compressor at the same time. Same loop field and pumps.
Short cycling is gone. It runs more efficiently. The backup stage doesn't run often. Zero cycles in the past three years. That still surprises us when temps drop. We'll look at 20 below readings and joke about how much better the system runs.
@dziskovs , I wish I had a simple answer. I know those short cycles are not helping. I'm assuming your system is sized to run geo below freezing if needed. There's got to be a better way to extend run times and slow resistive heat startup.
With our old system the separate stage and zone controllers didn't work well. Each zone call was essentially treated as more load and the system would ramp. Each zone shut down was another call to the controller. It was a real nightmare to set up.
I'm in a colder area but we don't typically run resistive heat unless geo can't satisfy the stat. It is set up as it's own stage and runs independent of the geo.
The run times with stages are awful short.
Geo systems should run more efficiently with longer run times because starting compressors takes power.
I had a geo setup at the house that was done in '03 initially. It was sized to use Geo down to zero F range and switch to backup if needed at that point. Integrated multi stage and combined zone controllers were not well developed at the time. It also had a two stage piston compressor. It was pretty clear when the ****** switched stages and it happened often. I struggled with short cycle times too. The setup lost efficiency with the short cycle times. Temps around zero made the system run like a city bus on a short stop route. Dang system was driving me nuts.
The zone controller was "tied" to another system controller and it just didn't work. I tried outdoor temp sensors as variable shutoff points between heat stages. I was able to extend run times a little because the system didn't keep swapping stages right at the edge of capacity. I was able to stay Geo heat with lower outdoor temps. It still went into backup heat more than I liked.
In 2017, I was working out of town and wife called. Heat wasn't working. I told her to get a tech in to get it going. Main board was kaput and the guy wondered how long we wanted to keep playing with this old controller setup.
Long story but the end result was replacing the whole controller setup with a stand alone stage and zone combined setup. Got rid of outdoor temp shutoff sensors. Swapped in a scroll ramp up compressor at the same time. Same loop field and pumps.
Short cycling is gone. It runs more efficiently. The backup stage doesn't run often. Zero cycles in the past three years. That still surprises us when temps drop. We'll look at 20 below readings and joke about how much better the system runs.
@dziskovs , I wish I had a simple answer. I know those short cycles are not helping. I'm assuming your system is sized to run geo below freezing if needed. There's got to be a better way to extend run times and slow resistive heat startup.
With our old system the separate stage and zone controllers didn't work well. Each zone call was essentially treated as more load and the system would ramp. Each zone shut down was another call to the controller. It was a real nightmare to set up.
The way my system is setup (now), is that it looks at Leaving Air Temperature (LAT) and Outside Air Temperature (OAT). I have an Arzel GTPro 3 zone control board. Stage Timers are turned off, and OAT Balance point is now turned off.
What that means is that for Oct, Nov, Dec, and part of January, when OAT Balance point was turned ON and set to 32F, anytime it was below 32 F, it would lock out the compressor and run backup Heat (W1 Call) only, and not run the compressor.
Now that I have the OAT Balance point turned to OFF, and we just lowered the OAT Balance point temp setting to 25F, if it is below 25F, then the Arzel board will run stage 1 compressor (Y1) for 3 minutes, check LAT, and if it did not satisfy the LAT of 88F, then it would stage up to Stage 2 compressor (Y2), run for 3 minutes, check LAT for 88F, and if not satisfied, it would stage up to resistive heat (W1) and run both compressor and resistive heat until call is met.
-Above 25F, it does the above, but W1 is locked out.
HVAC tech called Arzel tech support while he was here last week, and confirmed that the 3 minute stage up is hardwired into the arzel board, so nothing I can do to change that.
- We did change the LAT stage up setting to 80F, so now it will often satisfy the heat call with stage 1 (Y1) setting, but with OAT hovering around 40, Stage 2 (Y2) still kicks on a lot from what I have watched on the board. It also stays in higher stage once its there (it will not stage back down to Y1 if LAT temp is met is Y2). If another zone starts a call while the first zone is satisfied, e.g if Zone 2 is calling for heat, and bumps to Y2, then Zone 3 calls, Zone 3 will stay in Stage 2 (Y2) for as long as it is calling, even though LAT is well above 80F setpoint, and Zone 2 call is off.
I setup the Zone capacity stageup threshold to 65% with Zones 2 and 3 with 30% each, so technically, it should never stage up compressor if Zones 2 and 3 are both calling at the same time.
Based on the last few days of electrical meter readings, I think in general the settings changes are helping. It's honestly hard to tell though since outside temps have been fluctuating up and down so much over the last week or so. It seems like the zones are calling less frequently though, so I'm not sure if it had anything to do with the settings changes, or if its just fluctuating since its been a bit warmer out. Zones seem to get satisfied in 4-6 minutes of run time:
The Trane XL824 thermostats are potentially part of the problem, but I don't know that for sure yet. They run a PI control scheme to determine when to call, and I haven't figured out yet if they are maybe causing some of the issues with short run time and frequent calls.
RGausman
Active member
Hi,
I stumbled on this thread searching for ”welserver.com 2024”. I have been a member here for many years and also using the Web Energy Logger since 2008. My page on welserver.com
Http://welserver.com/WEL0058
When I began my GSHP install in 2007, I was searching for a logger to verify the system’s ground loop performance in real-time. Discovered WEL by Phil Malone up in Maryland. Over the years have made add many additions to WEL0058 system beside the HP such as house room temp, hot water heater, outside weather and now currently adding PV.
I bumped the t-stat setpoint up 3 degree to show performance in attached snapshot.
Unfortunately my electrical usage is not functioning while integrate solar so no kw for hp COP etc.
Some food for though…
Now as far high electrical usage, you do not know what can not be measure. Seen people complained about higher electricity cost after switching from gas/oil to GSHP. To true calculation, need to compare apple to apple. Meaning convert previous gas/oil usage kW costs.
Is the hot water tank connected to the GSHP? If not or not functioning then the HWT is using electricity. Last year my desuperheater exchanger coil started leaking and disabled it. Notice a higher electric bill may be about $50 per month.
Another area is the 3rd stage backup heat. In past there where some systems going into 3rd stage excessively. Most backup heat element are on a separate breaker. Could try turning breaker off and allow the system to run longer. Electric heating elements has COP of 1.
Close loop GSHP systems are design to operate at minimum with EWT at 30F degrees with usually antifreeze protection down to 15-17 so degree. Higher the EWT, better the performance.
Heating performance measured as COP and should be in the 3 to 5 range. Higher the better.
I believe every GSHP install should have at least one pressure and one temp gauge to monitor the ground loop performance at a glance.
Bob G.
I stumbled on this thread searching for ”welserver.com 2024”. I have been a member here for many years and also using the Web Energy Logger since 2008. My page on welserver.com
Http://welserver.com/WEL0058
When I began my GSHP install in 2007, I was searching for a logger to verify the system’s ground loop performance in real-time. Discovered WEL by Phil Malone up in Maryland. Over the years have made add many additions to WEL0058 system beside the HP such as house room temp, hot water heater, outside weather and now currently adding PV.
I bumped the t-stat setpoint up 3 degree to show performance in attached snapshot.
Unfortunately my electrical usage is not functioning while integrate solar so no kw for hp COP etc.
Some food for though…
Now as far high electrical usage, you do not know what can not be measure. Seen people complained about higher electricity cost after switching from gas/oil to GSHP. To true calculation, need to compare apple to apple. Meaning convert previous gas/oil usage kW costs.
Is the hot water tank connected to the GSHP? If not or not functioning then the HWT is using electricity. Last year my desuperheater exchanger coil started leaking and disabled it. Notice a higher electric bill may be about $50 per month.
Another area is the 3rd stage backup heat. In past there where some systems going into 3rd stage excessively. Most backup heat element are on a separate breaker. Could try turning breaker off and allow the system to run longer. Electric heating elements has COP of 1.
Close loop GSHP systems are design to operate at minimum with EWT at 30F degrees with usually antifreeze protection down to 15-17 so degree. Higher the EWT, better the performance.
Heating performance measured as COP and should be in the 3 to 5 range. Higher the better.
I believe every GSHP install should have at least one pressure and one temp gauge to monitor the ground loop performance at a glance.
Bob G.
Hot water tank is connected in series from geo to HW tank to Gas Tankless HW Heater. The HW tank is not plugged into wall (basically just an insulated reservoir, and Gas tankless heats water if demand/ temps call for it.
In general, I think the problems are mostly resolved after having to hound HVAC company for the last 4+ months about incorrect settings on the Arzel zone board. I've been tracking daily usage manually looking at the meter, and logging daily temps for the last 2 months. In general, I think the issues are mainly resolved, but I'm sure there is more room for optimization. For April, I have bumped up all thermostats to 70F vs. setpoint of 68F to see if there is quantifiable difference, but with temps going up, it won't be very scientific.
I'm still chasing Z3 higher runtimes vs. other zones, but have some remodeling to do and will check insulation on that zone while I'm at it this spring/ summer.
I point blank asked the HVAC company how they were planning to compensate me for the 100+ hours of monitoring and $1000+ higher utility bills after they finally "fixed" the issue by changing the arzel zone board settings. The response I got was "this is the normal way for the geo is to be set up and we have done this many times without complaint", and an offer to extend my service agreement by an additional year. At this point, I'm chalking up the higher bills to part of the install cost, and payback is going to be delayed by 1-2 years due to their incorrect setups. Hoping with the coming summer months I get a bit of relief on cooling costs.
wssix99
Well-known member
I got the same responses. Faced with higher legal bills vs. just eating the cost, I chose to rip into them with every 4 letter word I could think of and physically kick them out of my house.
This BS and installers not thinking/not reading the instructions shouldn't be part of the 'install cost.' I have come to see it as the expense from their cloak of ignorance is less expensive than the cost of a lawyer's shield of protection.