Maryland Climatemaster poor heating performance?

I am new to geo and heat pumps in general, so bare with me.

I bought a new house with a closed loop, vertical, geothermal system installed. The heating does not seem to be performing as expected. I first noticed that the aux heat would kick on very frequently and it would be what is running most of the time. That was starting to get expensive very quickly judging by our power meter. I was able to disable the aux heat through the demand reduction feature, however the geothermal system cannot keep up when the outside temperature is below a certain temperature, say like 25-30 degrees F or less. So the temperature at the thermostat seems to drop over time even though I only have it set for 66F. The system runs 24 hours a day on heating 2 and still cannot keep up

It seems that the return air temperature never gets above a 15 degree increase which seems low, at least according to the user manual, unless I am reading it incorrectly.

The Entering water never goes too far below 33F even when running for 24+ hours straight on heating 2. The following reading has an inside air temp at 65 F. and is on "heating 2" which I assume means the full 3 tons?



According to the performance chart I should be getting a minimum of 19F increase in leaving air temperature.



Like I said when the temperature is below something like 25F out or so, the system runs on heating 2 around the clock even when the tstat temp is only set for 66F. It seems to me like the return air temp just isn't warm enough. Please help me shed some light on this issue. Let me know if you need any additional information. Also any idea on how much electricity this uses when running on heating 2 at full load with no aux heat? Thanks in advance.

Steve

 

EWT seems fine. Unit running 24/7 may be OK if it is at design minimum outside temperatures. You probably should be getting higher tem increase, but may be too much airflow. It does seem the unit may be slightly undersized for your house. More info on location and design loads would be helpful. Since it's a new house your builder/installer ought to be able to provide that. There may be some easy insulation upgrades to resolve your issues. I expect one of the experts will chime in and let you know if 10 GPM at 5 degree drop is as expected with these units.

 

Target airflow is on the high side for a 3 ton unit (The IOM Table 10 shows the maximum airflow as 1500 CFM for the TE038). High airflow across the coil would contribute to a low 15 degree differential temperature across the coil. This high airflow target value is likely due to a dip switch setting on your unit control board. Typical airflow for a 3 ton Climatemaster unit ECM blower is ~1200 CFM (TE038 default value is 1050 CFM per Table 10). The higher airflow will typically slightly increase unit heating efficiency at the expense of comfort (cooler discharge air temperature). It looks like your unit may be operating fine but may be slightly undersized for the given temperature.

The table posted above looks like Table 15 on page 43 of the Tranquility 30 Digital (TE) Series IOM (I have a copy here on my desk). If you go to page 46 of that manual it shows performance data based on either 1100 CFM or 1250 CFM. Per the table with an EWT of 30 deg F with 9 GPM flow, 5 degree water side delta T, and 1250 CFM, your unit is only producing ~30.2 kBTU (HC) or approximately 2.5 tons of heating capacity. At 33 degree F EWT heating performance would be slightly higher at ~31 kBTU. It won't make the nominal 3 ton heating capacity of 36,000 BTU until EWT is around 45 deg F.

Do you know the calculated heat loss/gain numbers for your home? If not, how big is your home? Average or better than average insulation? Average or more square feet of windows? Average or better air infiltration? What about run time on ventilation systems including clothes dryer, kitchen vent hood, bathroom vent fans, etc?

Note also that the TE038 adjusts water flow to meet the set differential water temperature. 5 deg F differential is right on target and 9.7 GPM is about normal. 3 GPM per ton or 9.0 GPM for the TE038 is expected for pure water but I assume you have a mix of water and anti-freeze which explains the slightly higher flow rate needed to achieve the target temperature differential across the coil.

 

Hi and welcome!
Where are you in Md? Design temps and loads vary greatly throughout the state. The eastern shore is a whole other ball of wax. Any info on the loop construction?
Eric

 

I am in Anne Arundel county. The driller said that they drilled 3x 316 ft deep wells for the geo system. I will have to confirm with the geothermal contractor to see what information they have on the design of the system. We have a 2-ton system for the second floor that seems to work better and the air definitely is hotter coming out of the registers. The 3-ton system for the main floor is the one that seems to have difficulty raising the air temp by more than about 15 degrees.

 

The main floor of the house is about 2300 sqft. However about 600 sqft of that is two stories and one of those walls is all windows, this would make it an equivalent of 3000 sqft of air volume. I was beginning to think that the 3-ton might be slightly undersized especially with the two story area. It is a new construction house, so insulation should be above average, but we do have a lot of windows and doors. Plus we don't get a ton of natural heating from the sun during the day since we have a lot of tall trees surrounding us. I just wanted to make sure the equipment was performing as it should. I may look into getting a small pellet stove or something like that for some of these colder days to supplement the heating.

How much more efficient running at ~1475 CFM would it be than running it at ~1200 CFM or 1050 for that matter? I do notice that it is a tiny bit loud with that much air coming through the vents. Should I set that back down to 1200/1050?

The house did have a blower door test and it came back with a score of 2.6 ach50. Is that okay, or do you think I can tighten that up a bit more?

Do you know how much energy the TE038 uses when it is running at full load? I am just curious so I can estimate what it may cost to operate it in different ways.

Also I plan on buying a couple of ecobees, to replace the climatemaster thermostats so that I have more control over the system. Do you guys recommend them?

Thanks for all the great information, I really appreciate it.

 

We have a climatemaster 22 5 ton. My pressures are higher 160-180 range but I think that may be because its a 5 ton compressor. In stage 1 which is similar in size delivery air is about 86-88F for a thermostat set at 69F the airflow is 1450CFM. Is your system at steady state? It almost looks like it has not been running for a long period or someone is taking a shower Im just looking at hot water EWT and comp discharge which makes me think that. Im no expert by any means so take that into consideration in reading this.

Try turning the CFM down and see what happens 80F air must not be very comfortable unless your vents are in obscure places. But you may not get air going to far reaching places.

Also compare stage 1 to stage 2 at the same CFM. Its possible its not wired properly and never actually goes to stage 2 but reports its in stage 2.

 

This snapshot was after the system had been running constantly at full load for many hours. As far as I know the hot water EWT is not used for anything (I am assuming that can be used for preheating water that then gets fed to the hot water heater), I don't think this feature is hooked up. Could that feature be "disabled" and could that cause performance issues? What is the compressor discharge, and what should the value range be? Thanks.

 

Ok that makes sense for the EWT no performance issues to worry about. Unfortunately I dont have a answer for your question on compressor discharge only that mine is higher. But we may be comparing apples to oranges I have a 5 ton your running a 3 ton. Id suggest comparing stage 1 and stage 2 it looks like you might be running with a airflow rate for stage 2 but the compressor is in stage 1. I believe you can wire the thermostat incorrectly and have that happen. Its easy to test. You can turn the thermostat down a degree so it shuts off. Then wait 10 minutes and turn it back on. It will start in stage 1 then move to stage 2 after 10 minutes or so assuming the demand requires it to. Compare the statistics between stage 1 and stage 2.

 

Do you have any plumbing connecting your heat pump to your hot water heater?

 

I'm just down the road in Calvert County. I too have a pellet stove insert to supplement my geo. Mine was a Oil retrofit, so I had very significant limits on amount of electric available without significant power upgrade. I couldn;t do supplemental electric strip heat, thus the pellet stove. i highly commend bay SToves in Edgewater. They were great on my install and maintenance.