HVAC Performance Data and Control

[sponnath]

Christopher,

Thanks for all the details. I have a lot of measuring to do!

I will go forward with this and report results.

If you can give me the part number on that BAPI device, I would get one. I am planning on adding a SECU16 at my furnace to collect data and 1-wire temp sensors.

I am not using my RCS stage 2 at this time. I am just letting the furnace turn the stage 2 on after 15 mins. I am sure the Lennox then just leaves it on.

I am using Bill Porters heatpumpsmadeeasy.com board. It's just a couple of relays and a temp sensor that switches between heat pump and furnace. It does not consider the W2 output so I couldn't wire up the stage 2 of the RCS. I was thinking the other day that if I used HS to slowly bring the house up it wouldn't hit stage 2 but that seems a lot to ask HS and it violates the idea of HS as a primary controller with local control at each subsystem.

I have attached the schematic that Bill Porter sent me. I tried to ask him to validate my diagrams that are states from the thermosat forward but he sent the schematic instead. If you can tell me how I could return Stage 2 control to the RCS thermostat input, I could also add a relay that would allow HS to not allow Stage 2 when the differential is low enough.

Again, thanks for all your help. I am hopeful that this not only benefits me but others that might want to dual fuel. I got very little help in that regard from any of the vendors.

Steve

[sponnath]

Christopher,

I measured up the ducts.

With all open in normal mode, there's 344 sq.in. output with 258 of return.
With the two bedrooms closed, there's 275 output and 148 of return.
I was surprised at the reduction in return but that's it.
So, I would have 79.9% of output but only 58% of return if I also close off the returns.

Your suggestions?

[drozwood90]

Steve,

Why are you closing the returns?

--Dan

[cadillackid]

drozwood: I close returns because the purpose of my zoning is to maintain separate climates for separate areas of the house...

closing returns doesnt make sense if the purpose is simply to keep all of the rooms even tempered.. HOWEVER.. closed doors with open returns and closed supplies can cause problems depending on how large the opening under the door is...

I used to go on more than one service call per year where the complaint was that the fireplace smoked bad when the furnace was on....

in many houses, they were built with one central return in the ceiling for the whole house.. esp common in garden (1 story) condos or apartments...

typically these units would have a larger gap under the bedroom doors for the positive air pressure to escape...

enter in the paranoid teenagers and / or new fluffier carpet / thresholds that closed this gap... the bedroom supply would push a positive pressure usually sending the excess air out the window.. causing just a tad bit of a negative pressure on the main part of the house and wa-la no more draw for the fireplace.. (esp in a ranch where the chimney wasnt as tall)..

the same can happen by sealing off rooms with closed doors and their return open.. typically there is less return area than supply (sponnath house is perfect example).. so the air velocity in the returns is higher and at more of a vacuum... this room return (with its supply closed) is going to suck in air wherever it can get it.. likely from windows, electrical outlets, etc... which is cold air introduced into the house...

the operating part of the house will be positively pressurized.. which some of that air will get pushed out windows / outlets / fireplace/ and yes some right back into the closed off room (esp with a gap under the door)..

now for stage 2 control..

the Lennox furnace should have a jumper or switch setting to disable the timed stage 2 operation.. I would set this mode so you can control it...

the heatpump made easy board should have a W1 output that heads off to the furnace...
place a second wire from the W(wire going to W1 on furnace) output of the heatpump easy board.. to the input side of an Ocelot relay... go from the output side of the Ocelot relay to the W2 position on the furnace...

anytime you close the Ocelot relay and the furnace is already operating you should receive stage 2 (most have a 30 second or 1 minute delay)..

when you are done with stage 2 you open the Ocelot relay and the furnace goes back to stage 1 only...

because you are piggybacking off of the W Output terminal of the heatpump easy board you dont run the risk of running gas heat and heatpump at the same time except in defrost if your heatpump uses traditional instead of hot-gas-bypass defrost...

anytime the heat pump is in operation the W from the heat pump easyboard will be off (disabled) and since the Ocelot relay is fed by source from W you will be safeguarded...

if homeseer bombs you still have Stage 1 which as you know will heat your house still...

for some reason i forgot you use a heat pump.. you will for sure want temp sensors on the inlet and outlet of that indoor coil.. (remember to wrap them.. those pipes get wet in summer and in defrost)..

-Christopher

[sponnath]

drozwood: I close returns because the purpose of my zoning is to maintain separate climates for separate areas of the house...
the same can happen by sealing off rooms with closed doors and their return open.. typically there is less return area than supply (sponnath house is perfect example).. so the air velocity in the returns is higher and at more of a vacuum... this room return (with its supply closed) is going to suck in air wherever it can get it.. likely from windows, electrical outlets, etc... which is cold air introduced into the house...
the operating part of the house will be positively pressurized.. which some of that air will get pushed out windows / outlets / fireplace/ and yes some right back into the closed off room (esp with a gap under the door)..

OK,
- So closing my returns is good,
- Should I boost my return square inches to get closer to parity? For example, I could add a second grill or one larger grill in master bedroom and increase living room return to get get closer to even.

now for stage 2 control..
the Lennox furnace should have a jumper or switch setting to disable the timed stage 2 operation.. I would set this mode so you can control it...
the heatpump made easy board should have a W1 output that heads off to the furnace...
place a second wire from the W(wire going to W1 on furnace) output of the heatpump easy board.. to the input side of an Ocelot relay... go from the output side of the Ocelot relay to the W2 position on the furnace...
anytime you close the Ocelot relay and the furnace is already operating you should receive stage 2 (most have a 30 second or 1 minute delay)..
when you are done with stage 2 you open the Ocelot relay and the furnace goes back to stage 1 only...
because you are piggybacking off of the W Output terminal of the heatpump easy board you dont run the risk of running gas heat and heatpump at the same time except in defrost if your heatpump uses traditional instead of hot-gas-bypass defrost...
anytime the heat pump is in operation the W from the heat pump easyboard will be off (disabled) and since the Ocelot relay is fed by source from W you will be safeguarded...
if homeseer bombs you still have Stage 1 which as you know will heat your house still...
for some reason i forgot you use a heat pump.. you will for sure want temp sensors on the inlet and outlet of that indoor coil.. (remember to wrap them.. those pipes get wet in summer and in defrost)..

Yep, agree here except for one point. I will probably use an X10 contact closure control so that I can use X10 to open/close my stage2 without having to get HS back up and running. I used one of those X10 contact controllers for my humidity relay.
Went to the HVAC store today and bought my relay to tie in W1 for my W2.

Thanks for all this info. It will be great to get it where HS could cut off stage2 when the fast rise isn't needed or a that point where I am only a couple of degrees away from the setpoint.

Steve

[sponnath]

Christopher,
Maybe you know the answer to this one.
I started working with HSTouch again for my thermostat. I used the thermostat screen in iphone2.xml. I then added a device status string for my humidity sensor in the house that should read 35% and does in the designer editor. However, when I deploy it to my phone, it reads "Temperature 70" which happens to be the current thermostat temp. This applies to all of the text fields I added to that page to cover external temp, external humidity and the internal humidity already mentioned.
Have you ever seen this behavior in your HSTouch? If so, how the heck do I get around it? No HSTouch editor errors or any other action that would tell me I have an error.

[cadillackid]

I dont use the iphone HSTouch template so im not sure.. ive found some wierdness in trying to get devices to track though.. you might try making a brand new screen from scratch and just put that device on it to try... ive also had to put the script tag in the text field of a label before instead of using the tracking feature..

example in the text field of a label put [$SCRIPT=&hs.devicestring("A98")]

this helped me to get devices to display correctly.. if you are usiong a thermostat template it may be that when the screen runs your label is underneath the thermostat element itself or such..

-Christopher

[Steve Q]

OK,
- So closing my returns is good,
- Should I boost my return square inches to get closer to parity? For example, I could add a second grill or one larger grill in master bedroom and increase living room return to get get closer to even.

Steve

If you are not using the room, you could close off the returns and the supplies with one of those magnetic HVAC grill covers. Is it necessary to install automated dampers??

Perhaps I am wrong, but I don't think just adding another grill to an existing cold air plenum will have much impact unless the cross section size of the plenum is much larger than the grill. Usually the ducts are about the same size as the grill.

Regarding airflow; About a year ago, when it was time to change my furnace filter (24x16x4) for the winter season, I replaced the filter with a high performance "allergen free" filter. I thought this would be a good idea and might help my summertime allergies. I did not think about how much air flow restriction the filter would create. It caused my furnace to short cycle and perform very poorly. So, make sure you consider the type and size of filter as part of your HVAC design.

Steve Q

[sponnath]

If you are not using the room, you could close off the returns and the supplies with one of those magnetic HVAC grill covers. Is it necessary to install automated dampers??

Perhaps I am wrong, but I don't think just adding another grill to an existing cold air plenum will have much impact unless the cross section size of the plenum is much larger than the grill. Usually the ducts are about the same size as the grill.

Regarding airflow; About a year ago, when it was time to change my furnace filter (24x16x4) for the winter season, I replaced the filter with a high performance "allergen free" filter. I thought this would be a good idea and might help my summertime allergies. I did not think about how much air flow restriction the filter would create. It caused my furnace to short cycle and perform very poorly. So, make sure you consider the type and size of filter as part of your HVAC design.
Steve Q

Yes, I wondered how much value adding a grill or enlarging the current one would really help. There's only so much space between the wall joists.

I currently use those magnetic covers. I close off the return at the ceiling during the winter and open the one by the floor. Switch in summer. So I actually already have more grill available if I was willing to pull warm air from the top of the room.

[sponnath]

Christopher,

I have a thread running at http://board.homeseer.com/showthread...d=1#post959473 where I am discussing why I had to use the script command instead of just referencing the device string as the text object allows. RJH has chimed into that thread.

[sponnath]

Christopher,

Got a humidity question.

I was out looking around for a humidifier for my son and discovered that there are steam humidifiers. These are used I guess for high performance furnaces and heat pumps due to lower air flow and lower temps. Maybe this is why my old General 1040 had some trouble getting the humidity all the way up.

Should I be switching to a difference humidifier? I am not too thrilled about the additional electricity to run a steam humidifier.

Other ideas? I saw one thread where a guy added a 6" vent fan to his humidifier to up airflow.

Steve