geome
Advanced Member
Posts:987
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| 18 Dec 2009 10:39 AM |
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Guess it's my turn for a problem. About 11:00 PM last night our Envision 2 ton (dual stage) split system locked out on low pressure (Lo Press/Comp light). The red LED was on, but I can't remember if it was solid or flashing. The manual suggested resetting the system and to call the installer if it locked out again (and not to reset it anymore). I reset the system, turned the unit back on, and it has been running fine since then (about 12 hours so far).
I called the installer and they said to monitor it and call them if it locks out again or if we have any other problems. Should I wait for a problem or insist they come out to check the system? Can this be a fluke?
The unit was installed in April of 2009. Worked wonderfully until the lockout last night. This is our first winter with this system. Heat has been running since November. All circuit breakers were on, and the air filter was clean when the lockout occurred. We have a horizontal closed loop.
Also, the emergency heat did not automatically engage. Could some wiring or some switch settings have been missed between the compressor unit and the air handler during installation? If so, what specifically? It's my understanding that emergency heat should have automatically engaged. Kind of a blessing in disguise since I may not have noticed the problem if it did engage automatically.
Thanks!
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| Homeowner with WF Envision NDV038 (packaged) & NDZ026 (split), one 3000' 4 pipe closed horizontal ground loop, Prestige thermostats, desuperheaters, 85 gal. Marathon. |
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G.O. Joe
Basic Member
Posts:110
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| 18 Dec 2009 05:55 PM |
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Geome
Sorry to hear about your lockout. Hopefully it is just something minor or maybe a one time gremlin.
On the Envision models the low pressure lockout led besides the obvious may also be an indicator of a ComfortAlert fault. The ComfortAlert box flashes its own led with a code if it sensed a fault condition. One CA fault code is 18 hr consecutive run time but that alone should not cause a lockout. Most of the other CA fault codes are voltage and current related, some that can cause a lockout. If the CA is not flashing than you had a regular low pressure lockout. Low pressure lockouts in heating can be caused by low water flow, low EWT, low return air temp <50f, system under charged, or a TVX restriction.
Did your Prestige tstat display the lockout condition? Was it flashing? Some times the contractor does not have enough wires to wire everything. The L lockout terminal is usually the one left out.
I think the WF guy you talked to was misinformed when he told you the emergency heat would come on during a lockout without an output signal from the tstat. Now the Aux lockout by outdoor temp is not the best solution without being there to monitor the system. I think for now if the house is unoccupied I will set the AUX lockout to 50F and bring the outdoor sensor inside the house. This way the electric strips will come on if there is a compressor lockout at a temp that will keep the house freeze protected. I still think the best way to retard the Aux heat is a time delay relay set to at least 2 hrs. I just haven't found one yet.
Let me know if you are comfortable taking a peak inside the box. I have all the code and flash info here.
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craigb93
New Member
Posts:47
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| 18 Dec 2009 09:28 PM |
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Dayton Time Delay Relay $70.78
http://www.grainger.com/Grainger/items/4GY64?Pid=search
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geome
Advanced Member
Posts:987
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| 19 Dec 2009 07:50 AM |
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Sorry for the delayed response. We are dealing with 14 inches of snow with a little more expected. This is a big deal in Virginia... |
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| Homeowner with WF Envision NDV038 (packaged) & NDZ026 (split), one 3000' 4 pipe closed horizontal ground loop, Prestige thermostats, desuperheaters, 85 gal. Marathon. |
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geome
Advanced Member
Posts:987
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| 19 Dec 2009 02:56 PM |
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craigb93, thanks for the link.
G.O. Joe, thanks too! Here is some additional information/questions:
On the lockout, it's been a little over 1 1/2 days and still no additional lockout. The loop for this unit is a common loop shared with our all-in-one 3 ton unit. I wouldn't think the loop or pumps would be a problem (since there is no problem with the 3 ton unit), but there is a valve that "splits" the flow from the loop to both geothermal units. Not sure if the valve setting is accurate or not for the needs of the 2 ton unit. This or some of the other items you mentioned could be an issue. Return air temps are >50f. What is TVX?
I didn't notice any indication of a problem on the thermostat. How does the L terminal work, and how should it be connected? I'll check today to see if it is connected. I suspect not.
How does the comfort alert (CA) work? I thought I needed a CA WF thermostat for that, but from your reply, it sounds like there is components inside the compressor section for this. I'm willing to open the door (after a spider or two are relocated!) |
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| Homeowner with WF Envision NDV038 (packaged) & NDZ026 (split), one 3000' 4 pipe closed horizontal ground loop, Prestige thermostats, desuperheaters, 85 gal. Marathon. |
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geome
Advanced Member
Posts:987
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| 19 Dec 2009 03:40 PM |
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The L terminal is not hooked up to our split and our all-in-one systems. Should it be, what should it be connected to, and what will it do once connected? Thanks!
The Prestige manual states this:
"L terminal sends a continuous output when thermostat is set to Em. Heat, and acts as a system monitor when in Heat, Cool or Off modes."
What does the output do? Emergency Heat already works if I manually select it without L being connected.
Edit:
I may be getting ahead of myself...
If L is connected to the heatpump, it should get a signal from the heatpump if there is an equipment problem, right? So, if I jump L to the aux terminal, will the aux go on during a lockout? If this is the case, will aux run to satisfy the thermostat, or will aux run nonstop?
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| Homeowner with WF Envision NDV038 (packaged) & NDZ026 (split), one 3000' 4 pipe closed horizontal ground loop, Prestige thermostats, desuperheaters, 85 gal. Marathon. |
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G.O. Joe
Basic Member
Posts:110
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| 19 Dec 2009 06:45 PM |
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geome
Normally the L (Lockout Signal) is passed from the Envision control board to the thermostat as a flash code to the thermostat after a lockout. The thermostat will flash "Call for Service" or something like that. The flashing code could then be read at the thermostat without opening the box. Some compliant thermostats even tell you what the code is without counting flashes. I don't think Honeywell does this but it should at least flash a code when connected to L.
I am not sure of Honeywells implementation of the continuous L signal when set to Emergency Heat unless that signal could be used to enable a fossil fuel backup. Emergency heat set at the thermostat provides a W signal (electric strip) on a call for heat without any calls for the compressor.
The ComfortAlert is a compressor monitoring system inside the the compressor section. It is the comp part of the low pressure/comp lockout led. You can differentiate a low pressure warning from a comp warning by looking to see if the CA led is flashing inside the compressor section. It looks like this-
http://www.emersonclimate.com/en-US/products/electronics/comfort_alert/Pages/comfort_alert.aspx
If it is not flashing it was a low pressure lockout. If it is flashing I have to lookup the code to see if it was a compressor lockout. If you promise not to touch anything see if you can get me the flash count and I will look it up.
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Bill Neukranz
Veteran Member
Posts:1103
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| 19 Dec 2009 06:55 PM |
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Posted By geome on 12/19/2009 2:56 PM ... The loop for this unit is a common loop shared with our all-in-one 3 ton unit. ... there is a valve that "splits" the flow from the loop to both geothermal units. ... What is the valve for? You and I have the same equipment and the same set up - two WF Envision units connected to a common loop. I don't have a valve. I'd make sure there's no water restriction occuring due to the valve. At the bottom is an image of where my 2" water loop pipes split to serve each heat pump unit - no valve. Since you're using a common loop for 2 units, like me, check to make sure you have water loop check valves in place at each unit - otherwise you may be pumping some of your water simply from one unit to the other, bypassing the loop going into the ground. You can see a plumbing diagram of my set up here: http://welserver.com/WEL0043/ (gray lines). Best regards, Bill |
 Attachment: IMG_9939.jpg
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Energy reduction & monitoring</br>
American Energy Efficiencies, Inc - Dallas, TX <A
href="http://www.americaneei.com">
(www.americaneei.com)</A></br>
Example monitoring system: <A href="http://www.welserver.com/WEL0043"> www.welserver.com/WEL0043</A>
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G.O. Joe
Basic Member
Posts:110
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| 19 Dec 2009 07:11 PM |
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Do not jump L to Aux. It will run nonstop uncontrolled.
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geome
Advanced Member
Posts:987
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| 19 Dec 2009 08:15 PM |
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G.O. Joe, thanks for the information and the caution. I have had the door open before and I keep away from everything inside while the unit is powered. I see the comfort alert module and the alert and trip LED's. The only way (that I knew of) to reset the system was to turn it off at the breakers. I assume this would have cleared the alert if there was one (no lights were flashing when I just checked it). If I get another lockout, I'll check the module. I won't jump L to aux either.
It would be nice to have the L terminal connected. What should the L terminal be connected to? Once L is connected, would it cause a problem when I switch to Emergency Heat and L would then have an output going back through the L wire to wherever it is connected to?
Bill, thanks for your information as well. The incoming loop line between the pump and the compressors have a "T" in them. Just after the "T" (on the 2 compressor sides) there are 2 ball valves that the installer adjusted (or throttled) somehow. I didn't question the reason for the valves at the time of installation, but I am wondering about them now. I believe that both circulation pumps always run when either, or both, compressors run. Not sure if there are any check valves on the incoming or outgoing loop lines since they are covered in Armaflex and taped at the ends, but I can certainly ask the installer any questions that you believe to be prudent.
Is there any way to automatically engage Emergency Heat during a lockout other than raising my thermostat aux lockout to a point that I really don't want to and having the temperature drop 2-4 degrees?
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| Homeowner with WF Envision NDV038 (packaged) & NDZ026 (split), one 3000' 4 pipe closed horizontal ground loop, Prestige thermostats, desuperheaters, 85 gal. Marathon. |
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Bergy
Basic Member
Posts:277
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geome
Advanced Member
Posts:987
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| 19 Dec 2009 09:01 PM |
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Thanks Bergy. Do you have a drawing with 1 flow center with 2 pumps? That's what we have. |
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| Homeowner with WF Envision NDV038 (packaged) & NDZ026 (split), one 3000' 4 pipe closed horizontal ground loop, Prestige thermostats, desuperheaters, 85 gal. Marathon. |
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Bergy
Basic Member
Posts:277
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| 19 Dec 2009 09:10 PM |
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Geome,
Sorry... I do not have a drawing for that. We always use separate pump packs. If one goes down there is still heat for the house.
Bergy
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Bill Neukranz
Veteran Member
Posts:1103
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| 19 Dec 2009 11:03 PM |
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Posted By Bergy on 12/19/2009 8:59 PM
Geome,
The piping for two heat pumps on a single loop field should look like this...
Bergy
Mine is this way too. See reference for my diagram, in my posting to this thread a little earlier. Best regards, Bill |
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Energy reduction & monitoring</br>
American Energy Efficiencies, Inc - Dallas, TX <A
href="http://www.americaneei.com">
(www.americaneei.com)</A></br>
Example monitoring system: <A href="http://www.welserver.com/WEL0043"> www.welserver.com/WEL0043</A>
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Bill Neukranz
Veteran Member
Posts:1103
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| 20 Dec 2009 08:32 AM |
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Posted By G.O. Joe on 12/19/2009 6:45 PM ... the L (Lockout Signal) is passed from the Envision control board to the thermostat as a flash code to the thermostat after a lockout. The thermostat will flash "Call for Service" ... The flashing code could then be read at the thermostat without opening the box. ...
This is exactly how my WaterFurnace labeled White Rogers tstat works on my non-zoned Envision unit.
Best regards,
Bill
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Energy reduction & monitoring</br>
American Energy Efficiencies, Inc - Dallas, TX <A
href="http://www.americaneei.com">
(www.americaneei.com)</A></br>
Example monitoring system: <A href="http://www.welserver.com/WEL0043"> www.welserver.com/WEL0043</A>
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geome
Advanced Member
Posts:987
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| 20 Dec 2009 08:55 AM |
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This is a picture of the flow from our ground loop. Please correct me if I'm wrong, but it doesn't appear to me that check valves are necessary with this setup since the flow from both circulation pumps (on the flow center) should prevent back flow issues.
Just noticed that I forgot to include the 2 ball valves. They are both immediately after the one "T" with the water flow entering the geothermal units. There are no valves on the "T" with the water exiting the geothermal units.
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Attachment: Dual 1 flow center.JPG
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| Homeowner with WF Envision NDV038 (packaged) & NDZ026 (split), one 3000' 4 pipe closed horizontal ground loop, Prestige thermostats, desuperheaters, 85 gal. Marathon. |
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Bill Neukranz
Veteran Member
Posts:1103
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| 20 Dec 2009 09:24 AM |
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Interesting. Perhaps other experts will comment that this is a common in-the-field design for one loop serving two units setups.
I'm going to guess the ball valves are completely open at the moment, because their purpose is probably for on/off control in case maintenance is needed on one unit but not the other. It's tough to use ball valves to adjust flow with. But, it seems strange, without one-way valves, that this set up would work for doing maintenance. Since you don't have valves on the exiting pipes, I'll bet you've got one-way valves under your water loop pipe insulation, and just haven't noticed them yet. They're not obvious looking items.
The design observation I have is that your flow center pumps have to be sized to adequately pump enough water through both units, in 2nd stage. It strikes me as a less efficient design, since if, for example, you're only using one unit, in 1st stage, you're still consuming pumping power for 2 units in 2nd stage. That's a lot of pumping power that's going to contribute to an increased kWh consumption level versus what you'd have if you have separately sized pumps for each unit.
Best regards,
Bill |
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Energy reduction & monitoring</br>
American Energy Efficiencies, Inc - Dallas, TX <A
href="http://www.americaneei.com">
(www.americaneei.com)</A></br>
Example monitoring system: <A href="http://www.welserver.com/WEL0043"> www.welserver.com/WEL0043</A>
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Palace Geothermal
Veteran Member
Posts:1609
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| 20 Dec 2009 12:09 PM |
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Bill, the one flow center for two heat pumps is a common practice. Many manufactures show this arrangement and teach it in training.
You concerns about this pumping arrangement are spot on. Our approach on this is to split the flow center and use one pump for each heat pump. |
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Dewayne Dean
<br>www.PalaceGeothermal.com<br>Why settle for 90% when you can have 400%<br>We heat and cool with dirt!<br>visit- http://welserver.com/WEL0114/- to see my system |
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Bill Neukranz
Veteran Member
Posts:1103
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| 20 Dec 2009 12:35 PM |
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Dewayne, I learn stuff from you all of the time. Thanks. I didn't know the one-flow-center-for-one-loop-for-two-units is a common practice. I guess it's less expensive because it's less labor to install a flow center intact versus pulling it apart and installing the pumps a la cart. And it's probably less expensive than installing everything custom (i.e., pumps and purge ports).
In my case, I have the custom arrangement (including purge ports outside where it's more convenient to hook up to versus up in the attic). And the number of pumps I have for each unit varies as a function of the unit's capacity. The first image is a one pump a la cart 'flow center' for a 3 ton 2 stage unit, and the 2nd image is a 2 pump 'push-pull' set up for a 5 ton 2 stage unit.
Hopefully you're sizing your pumps to well match the pumping power needed, and are using pumps that are 2 speed to further conserve kWh when a unit's running in 1st stage. Mine consume a good 800 or so watts each, making pumping kWh consumption about a one-third energy 'add-on' to each unit's heating/cooling operation. Knowing you, you're probably giving your customers a more efficient set up.
Geome, take a look at the upper left corner of each image for what the one-way valves look like. Each are behind the yellow handles on the ball valves. They're difficult to notice, and thus my earlier comment that you may have them and just not know (yet).
Best regards,
Bill |
Attachment: IMG_9936.jpg
Attachment: IMG_9915.jpg
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Energy reduction & monitoring</br>
American Energy Efficiencies, Inc - Dallas, TX <A
href="http://www.americaneei.com">
(www.americaneei.com)</A></br>
Example monitoring system: <A href="http://www.welserver.com/WEL0043"> www.welserver.com/WEL0043</A>
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geome
Advanced Member
Posts:987
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| 20 Dec 2009 03:33 PM |
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We have a closed horizontal loop and fortunately our pumps are only 245 watts each (if my Danish is correct). For a vertical loop this setup wouldn't be as cost effective (based on 800 watts per pump). I suppose we could get our setup more efficient, but not sure if the payback would justify the cost given the relatively low wattage pumps. Your pictures are great. We may have the one-way valves. I'll ask the installer the next time I speak to them.
Getting back to some unanswered questions:
What do I connect the L terminal to for it to act as a system monitor? (Not on the thermostat side, the other end of the wire).
What does the L terminal output designed to do? As an input, it acts as a system monitor. Our Emergency Heat already works if I manually select it without L being connected.
Once L is connected, would it cause a problem when I switch to Emergency Heat and L would then have an output going back through the L wire to wherever it is connected to?
Is there any way to automatically engage Emergency Heat during a lockout other than raising my thermostat aux lockout (to a point that I really don't want to) and having the temperature drop 2-4 degrees?
Should I wait for another lockout or insist the installer come out to check the system? |
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| Homeowner with WF Envision NDV038 (packaged) & NDZ026 (split), one 3000' 4 pipe closed horizontal ground loop, Prestige thermostats, desuperheaters, 85 gal. Marathon. |
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