khonderd
New Member
Posts:36
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| 27 Sep 2011 10:12 AM |
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First of all, thank you VERY MUCH for all the contributions to this site. It gave me the knowledge to insist on a preheat tank for my desuperheater, along with plumbing it to avoid sediment issues that would be sure to be problematic with our well water. I have also found answers to a lot of other questions I've had on here.
I have a Bosch TA035 3 ton, 2 stage, variable speed blower, ground loop geothermal system installed about a month ago. When I set the thermostat to call for heating it blows room temperature (initially blew cooler than room temperature until I sealed up some major gaps in the unconditioned space return vents from the initial install) air for 5 minutes before the air coming from the register starts to warm up. I've tested this with a thermometer so I know the air doesn't just "feel" room temperature, but actually is, and I can see it start to climb almost exactly at 5 minutes. Is this normal? The wife would prefer not to have what feels like cool air blowing for this 5 minutes, but it isn't a big deal if it is normal. I couldn't find anything in the operating manual, install manual, specs, nor with a google search, so I'm hoping someone here can help me.
One thing she isn't willing to put up with is a whistling noise coming from the vents, but the search function has given me many suggestions to try and track that down. |
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joe.ami
Veteran Member
Posts:4377
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| 29 Sep 2011 08:11 AM |
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The fan can be responding to presets (dip switches) in the heat pump or a thermostat program. Same dip switches may allow reduction in blower speed to help with noise.
j |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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khonderd
New Member
Posts:36
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| 29 Sep 2011 09:51 AM |
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1) So does a typical geo heat pump take 5 minutes to warm up before it starts outputting heat? I've timed it and it is almost exactly 5 minutes at which point the air starts increasing in temperature. I'm fine with this if it is how it is supposed to work, but wanted to make sure it isn't an issue w/ mine.
2) My installer is probably going to want to reduce the blower speed to get rid of the whistle noise, but won't that reduce the overall amount of heat that is output? Wouldn't it be better to find the source of the noise and eliminate it if possible? It appears to be coming from the main supply duct, so I wouldn't think that would be too difficult to find. Would installing duct liners at that point possibly eliminate it? I've already taped all the joints in that area with foil tape. |
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decafdrinker
Basic Member
Posts:420
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| 29 Sep 2011 10:41 AM |
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There could be a couple different things that might cause such a delay. One might be that the heat exchanging coil truly does take 5 minutes to bring any extracted heat into the airstream, but most geo units start producing some heat almost right away, which gradually builds.
It could a setting somewhere with the variable speed and/or the thermostat that causes the system to turn on the circulating fan a few minutes early. I've seen ads for systems that will try to meet the heating or cooling demand first by simply turning on the circulating fan. Sometimes warmer or cooler air in another part of the house can be drawn in and used. We could agree this is most economical. After a few minutes of doing this, the thermostat would determine it's not sufficient to just use the fan, and then it would activate the compressors.
What kind of thermostat is it? Can you verify that the compressors of the unit are coming on when the fans come on, or do the compressors wait 5 minutes also?
Regarding the whistling...again it could be a couple things. If it's a hole or a sharp edge inside the trunk, then sealing/smoothing/padding could completely solve the problem. If it's because the trunk isn't big enough for the quantity of air coming through it, then you'll either have to dial the speed down, or add a bypass damper. If it's a zoned system, you might also be able to set the zone dampers to not fully close in order to siphon off some of the excess air. For maximum efficiency, the system should be running at the optimum speed taking into account the tonnage, the heat extraction, and the duct size.
Any way you can record the sound with your laptop or something and upload it for us to hear? |
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Palace Geothermal
Veteran Member
Posts:1609
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| 29 Sep 2011 11:09 AM |
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Posted By decafdrinker on 29 Sep 2011 10:41 AM
Can you verify that the compressors of the unit are coming on when the fans come on, or do the compressors wait 5 minutes also?
This would be good to find out. 5 minutes seems like a long time to wait. |
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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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khonderd
New Member
Posts:36
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| 29 Sep 2011 11:21 AM |
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Thanks for the reply. The thermostat is a Carrier TP-PHP01 'Edge Performance Series'. I'll check tonight to see if the compressor is running when the fans come on, along with taking pictures of the duct work and recording the whistling.
One anoying thing with the thermostat is that it only allows 10 minutes on stage 1 before it kicks into stage 2. Since 5 minutes are used up just circulating the air that means I only get 5 minutes on stage 1. I've checked the settings and the only option it gives is to change the length of time the system stays on stage 2 before going to aux heat, which shouldn't come on anyways because I have the outdoor sensor lockout enabled. I'm considering seeing if my installer could replace it with a different one.
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khonderd
New Member
Posts:36
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| 29 Sep 2011 11:44 AM |
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I'm assuming that I can check if the compressor is running simply by listening for the vibration sound. Is this correct? |
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decafdrinker
Basic Member
Posts:420
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| 29 Sep 2011 03:20 PM |
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Correct. You should hear some sort of heavier vibration when the compressors actually start.
I'm surprised about the 1st stage/2nd stage delay also. Most smart thermostats and control boards allow the thermostat to use gathered data about how the house is heating/cooling to determine what stage should run, rather than an arbitrary number of minutes. Do you have a zoning panel of any kind? Do you have manuals for the thermostats and/or is something set to TIMER for stage control rather than "TSTAT" or something? The "smart thermostats" should be automatically delaying things like Stage 2 in the interest of energy savings. Something here is not quite right. |
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khonderd
New Member
Posts:36
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| 29 Sep 2011 03:46 PM |
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I don't have a zoning panel and I've read through both the operators and installation manual several times, but could have missed something. I'm having internet issues so I can't find the link, but the manual is on the Carrier Residential website. Feel free to check it out and see if I've missed anything. |
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khonderd
New Member
Posts:36
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| 30 Sep 2011 01:06 AM |
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Here are some answers to questions I've been asked.
The compressor does not start until after the 5 minute period of circulating room temperature air. Once it does start it warms the air up quickly.
I'm attaching pictures (hopefully it works) of the duct work. The return duct is 28x10 and the supply duct is 16.5x16.5. Since this is the same size as the opening on the top of the geosystem, and gets slightly bigger from there I would presume it is big enough, but that's just a guess on my part.
I didn't have a chance to record the whistling noise yet. I did do a couple tests. I ran it without the cabinet door on for a few minutes to see if that caused the whistling to stop. It didn't. I also ran it with the filter out for a few minutes and it still didn't stop.
Please ignore the duct tape on the fabric portion of the duct work. That is just temporary until everything is set up. Also, I am still waiting for the inspector to come check out my system and didn't want to insulate my water heaters or duct work until he has given me the OK that everything is good to go. |
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Palace Geothermal
Veteran Member
Posts:1609
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| 30 Sep 2011 01:37 AM |
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Posted By khonderd on 30 Sep 2011 01:06 AM
The compressor does not start until after the 5 minute period of circulating room temperature air. Once it does start it warms the air up quickly.
This is not normal for a heat pump and the source of your frustration. Heat pumps are not set up that way so I suspect your thermostat. |
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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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joe.ami
Veteran Member
Posts:4377
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| 30 Sep 2011 09:01 AM |
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Duct size of most interest is the horizontal trunk. An installer is not likely to shrink the outlet size of a heat pump, but that doesn't mean he won't use a 20X8 trunk where 200" or more of duct are required.
I agree with Dewayne. If your blower truely is running 5 minutes before compressor cycles on then the stat is the likely culprit.
j |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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khonderd
New Member
Posts:36
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| 30 Sep 2011 09:07 AM |
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Thank you both. I'll check tonight if the thermostat is sending just the blower signal, or both the blower and stage 1. I should have thought of checking that before as that will tell me whether the culprit is the thermostat or the heat pump. I'll also get some measurements of the horizontal trunk (both return and supply) also.
FYI - This is a retrofit, not a new install.
Edit: Looking above I don't see the pictures I uploaded. I'm assuming nobody else sees them either, right? I'll try again tonight if that is the case. |
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joe.ami
Veteran Member
Posts:4377
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| 30 Sep 2011 09:14 AM |
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BTW if installer used aftermarket soft start, some have time delays as well. |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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khonderd
New Member
Posts:36
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| 01 Oct 2011 11:12 PM |
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I tested the system again and the thermostat is calling for stage 1 heat with compressor immediately after turning on the heat pump, so the heat pump must be the issue. The installer is going to check out both the 5 minute delay and the whistling noise next week so I'll let everyone know where everything stands at that point.
On a related note, since the thermostat only calls for at most 10 minutes at stage 1, I'm going to see if he will provide a different one. I know the White Rodgers is highly recommended but I ran across a post the other day that mentioned a thermostat that displays 4 temperatures at once, such as outside air, buffer tank, EWT & LWT, if those items were wired up. Of course I can't find the post anywhere. Anyone know what that thermostat was, or have any suggestions for others? |
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khonderd
New Member
Posts:36
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| 03 Oct 2011 03:47 PM |
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While I'm waiting on the installer (coming Friday) I'm wondering about someone's suggestion to put a check valve between the main tank and the buffer tank. The main tank is new and should have a heat trap nipple in it. Would I still need the check valve if that was the case? My electric bills have been fairly high and I'm wondering if the main tank is trying to heat up the buffer tank too.
Also, I'm thinking the 1F95-1277 thermostat is my best bet if I want to be able to make it run on stage 1 for longer (instead of the 10 minutes my current thermostat runs on stage 1). Can anyone verify this, or suggest alternatives? |
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joe.ami
Veteran Member
Posts:4377
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| 04 Oct 2011 07:38 AM |
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Just because your thermostat indicates a call for stg 1 right away doesn't mean it's not going through a 5 minute delay.
I do not install check valves between buffer and finish tanks.
Your electric bill is high compared to what?
j |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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khonderd
New Member
Posts:36
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| 04 Oct 2011 08:20 AM |
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Perhaps I need to clarify. My thermostat sends a signal to the stage 1 wire on the heat pump right away, as confirmed with a circuit tester. I would think that would mean the heat pump is delaying the start of the compressor, but I know little about these things compared to you guys so perhaps I'm wrong. I'm just going by what seems logical to me.
My electric bill is high compared to what it had been last spring. This is on days when the geothermal wasn't running, and wasn't even turned on. The only difference is that our main hot water heater is electric now instead of propane, and we have a buffer tank now. I expected it to be higher but I was surprised that on some days it is 20-30KW higher than it was last spring. I had seen a post (I think from engineer) that said his WEL server showed a considerable use of electric by his water heater until he put a check valve in. I'm wondering if that might be happening with mine, but I would think the heat trap nipple would stop this, assuming the installer didn't take it out.
I do realize that it is possible my family simply uses 20-30KW of water heating on some days and just didn't relize it with the propane tank, but was hoping to eliminate the possibility of it running extra because of the buffer tank.
As for the heat pump, I'm very happy with the amount of electric it has used (approx 1.7KW on stage 1; 2.5 on stage 2) on the nights it has run, although I'm going to be kicking around ideas to keep it from engaging stage 2 so early if the installer doesn't give me a different thermostat. For now I've temporarily disconnected the thermostat wire that calls for stage 2 because it isn't overly cold out and stage 1 can keep up. The whistling of stage 2 was waking my wife and one of my kids. |
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joe.ami
Veteran Member
Posts:4377
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| 05 Oct 2011 07:40 AM |
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Yes if Y1 wire is hot then delay is downstrem of thermostat.
Yes it is possible your family uses 20kw/day for hot water. |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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khonderd
New Member
Posts:36
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| 10 Oct 2011 08:27 AM |
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My installer came over to check out my system. He could hear the whistling but didn't think duct liners would be effective in eliminating it. He instead suggested turning down the blower speed, but wanted to do a little research regarding the ramifications before actually doing so. This weekend I scanned the installation booklet and discovered the following.
"If air noise or excessive air flow are a problem, the blower speed can be changed to a lower speed to reduce air flow."
But then in a different area I found: "Do not set the ADJ jumper to the (-) setting when electric heaters are installed. Doing so may cause the heaters to cycle on their thermal overload switches, potentially shortening the life of the switches."
Since the way to reduce the blower speed is to set the ADJ jumper to (-), and since I have electric backup heat strips, it sounds like a bad idea to move it, which brings us back to the duct work.
At that point I realized I never posted all my duct work figures, so here they are:
Return: 8x20 up above with a drop down of 10x28 to the heat pump. The whistling doesn't appear to come from the return side, but the supply side. Removing the blower door did nothing to reduce the whistle effect.
Supply: 16.5x16.5 at the heat pump which expands to 16.5x20 before it is capped at the top with 3 runs coming from the sides. The three runs are as follows:
1) 8x18, which reduces to 8x14 after about 5 feet with no other vents exiting before that point
2) 8x10
3) Approx 7" diameter circle duct
Does this appear to be sufficient duct work for 1200CFM air flow? |
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