Fist off I want to say thank you to a number of you for assisting me with my problem this time last year. It was because of this forum I was able to correct an issue causing me extremely high electric bills. Unfortunatley a year later I now have a new issue. My wife keeps the tstat set to 70 (keeps her warm and happy). The past month or so on really cold nights the overal temp in the house will drop to 65 or 66 during the night and the aux heat kicks on. My Climate Master is unable to keep up. The past two weeks I've had the company who installed the geo unit out twice. The last technician seems to think there may be an issue with my loop field. Unfortunately, I no idea how many feet I have, I am working on contacting the company that installed the lines to get all the detailed information. I have the ClaimateMaster Tranquility 4 ton unit I believe. I know in order for you guys to really assist me I need to get detailed information concerning the field loop. I know my ETW is 27 and the LWT is 22, to me that is too cold. Also, I live just north of Cincinnati Ohio. I am starting to believe I don't have enough feet of lines out in my yard but I can't trully say that so any assistance from this forum would be greatly appreciated. The company that installed the unit wants to get the company that installed the lines with the Climate Master sales rep to meet at my house to determine if the field loop is sized appropriately.

Is this a new problem or did you not get adequate heating last year? If this is a new problem and you heated adequately last year it prolly is not the loop field. You also could be at your units balance point. This will not be easy to solve withut the specific information about your design, both for the loops and the house, i.e. manual j ect.
Eric

A EWT of 27 seems pretty cold to me as well. Wonder if you have enough flow or maybe there is air in the loop field. Did the tech do any other readings (like pressure) which you could post?

Everything I don't know what the weather has been of late in your area but I've read it has been mild pretty much everywhere. An EWT of 27 suggests there may be a waterside problem. LWT of 22 suggests to me it is not a flow problem - 5 deg Delta T suggests good flow.

If one or more loops is airlocked that could cause the remaining participants to become colder than designed

While not ideal 27F in the loop field is not alarming in itself- I've mentioned before that EWTs are a snap shot in time and the shorter the loop field (i.e. vertical vs horizontal) the quicker the EWT drops during a cycle.
There are other questions that need to be answered for us to help (see post by waterpirate).

I will make every attempt to get the specifics behind the design of the loop field this week. I know I don't have the specifics so help will be at a minimum. The pressure inside the loops are 56 psi in and 50 psi out.

WaterPirate, when you say 'You also could be at your units balance point', what do you mean? I will make a call tomorrow and see if I can't get the manual J calculation from the company that installed the unit. Hopefully, they still have this information. THANKS!

A units balance point, or more specifically the balance point for your design is when the unit is making it's maximum amount of heat and the thermostat is not satisified. This is where stage three heat strips can close the gap. This is also a slipery slope due to the longer the unit runs, the lower the ewt will get, further reducing performance. This is the worst possible scenario and all other dignostics need to de done before ringing this bell.
Eric

Posted By waterpirate on 22 Jan 2012 08:06 PM
A units balance point, or more specifically the balance point for your design is when the unit is making it's maximum amount of heat and the thermostat is not satisified. This is where stage three heat strips can close the gap. This is also a slipery slope due to the longer the unit runs, the lower the ewt will get, further reducing performance. This is the worst possible scenario and all other dignostics need to de done before ringing this bell.
Eric

"Balance point" is the designed temperature (in heating dominated climates)at which auxilliary must contribute to reach designed set-point. That's all........all properly designed systems have a balance point, in my AO it its in the mid teens. ...Properly designed loop fields will not plunge much below design parameters regardless of balance point. A heat pump does not extract more heat from the ground simply because the auxilliary heat is on. In fact those who interfere with the operation of their auxilliary coils are more at risk of falling below design temps on loops.

Thanx for the clarification Joe. The caveat here is "all properly designed systems". We tend to talk about balance points in terms of failures here. If it is working properly no one seems to talk much.
Eric

The info you gave us so far indicates that so far your unit seems to be sized OK. It is normal that the aux heat comes on at very cold nights.

Delta t of 5 degrees looks also good in second stage.

While we shoot for above 30 degrees in designing loopfield temp, 27 is not catastrophic. It might cost you $40-$60 a year more, but that is about it.

A few things on the con here: The winter has been very mild, thus 27F EWT would have been even lower in a "normal" winter. We are also see the lowest loopfield temps mid-end February, and we are not there.

On the pro side here is the fact that the loopfield usually takes 1-2 years for the ground to compact around the pipes. In the first year, some loopfields run down to 25 EWT, second year around 30, and third year around 31-32F.

How old is your loopfield?

Any info about loopfield design would help.

This is the second year for the loop field. Here in Dayton, Ohio we have had a very mild winter. Today we started the day off with 55 degrees, though right now it is 40. The system runs great when the days are in the 30's. At night, when it drops down in the 20's, it simply can not keep up. I have two zones with the upstairs being on the second zone, or so I thought. Since no one lives on the second floor, I have it set to 63. Today, I decided to increase it to 65 and then went to the basement. I was expecting the sedond zone indicator to come on but Zone 1 came on instead. Last year, that was not the case. Last week, the pump on the entering line went out, it was running SUPER hot, so they replaced it. I noticed in the technicians notes he rewired unit. I get the sense he wired the upstairs to run on zone 1 when it should be operating on zone 2. I have the name of the loop installer and plan on giving them a call tomorrow to get the specifics on my loop field. Thanks everyone for all your help.

It sounds like the HVAC contractor that installed your unit contracted out the loop field in your yard? If that's true, that's very odd.

Posted By OhioBuckeye on 23 Jan 2012 07:45 PM
This is the second year for the loop field. Here in Dayton, Ohio we have had a very mild winter. Today we started the day off with 55 degrees, though right now it is 40. The system runs great when the days are in the 30's. At night, when it drops down in the 20's, it simply can not keep up. I have two zones with the upstairs being on the second zone, or so I thought. Since no one lives on the second floor, I have it set to 63. Today, I decided to increase it to 65 and then went to the basement. I was expecting the sedond zone indicator to come on but Zone 1 came on instead. Last year, that was not the case. Last week, the pump on the entering line went out, it was running SUPER hot, so they replaced it. I noticed in the technicians notes he rewired unit. I get the sense he wired the upstairs to run on zone 1 when it should be operating on zone 2. I have the name of the loop installer and plan on giving them a call tomorrow to get the specifics on my loop field. Thanks everyone for all your help.

Sounds more like a zone controller / thermostat issue to me.

Posted By robinnc on 23 Jan 2012 10:25 PM
It sounds like the HVAC contractor that installed your unit contracted out the loop field in your yard? If that's true, that's very odd.

I am curious why you find this odd?
Eric

Personally I do not want to see a hvac trained technician outside digging and playing in the mud and dirt.  I also would not want a union excavator inside wiring up my thermostat.

We sub out the excavation, but our technicians install the pipe, fuse it and bring it into the house. That way we have more design input, and can more custom design the loopfield. IT also helps to understand the nance differences between certain loopfield designs, so more attention can be paid to certain details. For example, a vertical installed slinky needs more purging power than a horizontal one. Some other contractors sub out the whole loopfield, which works well for them too. It depends what routine you have for the processes.

docj....why would the HAVC contractors 'contract' out the complete horizontal loop? That to me seems like they have no resposibility for the loop field since they didn't install it?

They certainly maintain the responsibility to the customer. Loop installer can provide a fantastic service to HVAC companies (and their customers) who are not that familiar with the geothermal concept yet. Because they have the experience, they actually lessen the risk to the contractor and the customer. Keep in mind, most of the install and design deficiencies come from the loopfield. The heatpumps themselves are very forgiving and operate through an extended range of conditions. So there is nothing wrong to have an experienced loop installer helping some freshmen to make the transition to geo, or to provide their service to geo companies who want to do only the inside work. Plus, it is even more common for vertical loopfields. Most installer sub vertical loopfields out to drillers. Same concept.

We sub out the excavation and the drilling, but do the fusing and all horizontal pipe ourself. We have also been hired as subs for HVAC companies who wanted to do the inside only.

Posted By robinnc on 24 Jan 2012 10:07 PM
docj....why would the HAVC contractors 'contract' out the complete horizontal loop? That to me seems like they have no resposibility for the loop field since they didn't install it?

I'm one of the companies that doesn't care to do the outside work. We have a loop contractor who will instll to our specs. Then I don't have to be a heavy equipment operator/maintainer, nor a CDL driver (slinkies don't travel well in small trucks). I also don't have to be in charge of basement wall penetrations that occasionally leak, or purchase/maintain expensive tools.

Years ago (as Doc suggests) an experienced loop contractor kept me out of trouble. Years later I trained an excavator buddy.

Many heating companies are small shops and keeping expensive equipment and operators is less desirable than hiring it out.

joe

Good info in this thread. What was the installation method of the OP? Horizontal trench, vertically drilled, horizontal bore? How deep was the pit or wells? What was the spacing on slinkies or wells? Was grout used if drilled? Not drilling mud, but actual grout with a thermal conductivity rating? How many feet of pipe was installed? Was it 3/4", 1", 1 1/4"? Just some questions if you can get a hold of the loop installer. Hopefully they have some records for the job.

Related to the above posts, our company subcontracts on the loopfield side only. Our strengths are in horizontal directional drilling (hdd) and HDPE fusion for geothermal systems. We understand how to put a correctly sized, grouted (which some horizontal drillers don't do), reverse close headered system in the ground and then into the house.

On the other hand, we understand that we are not HVAC contractors. An HVAC contractor who has been working with duct, calculating manual j and installing furnaces in houses for years has a completely different skill set. This becomes even more apparent when you look at larger commercial jobs: vertical driller, mechanical contractor, electrician.