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Thread: Some dual fuel questions
10-28-2012, 10:40 PM #1
Some dual fuel questions
hey guys. This past may i installed a lennox xp15, matched with a lennox el furnace with propane and a honeywell pro 6000. We can just the heat pump for the cooler spring days, and just recently had the gas company come install the tank, and run the lines to the furnace.
So, im heading up there tomorrow to set up the system for winter operation.
Now please keep in mind, that this is a cottage, and people are only here on the odd weekend, so for the majority of the winter, the system is going to be just used to keep cottage water lines from freezing.
So i have already determined i will set my cutout at 2 degrees C for our switchover. I have installed an outdoor sensor for the switchover.
A couple questions i need answers for.
1) Thermostat set backs.
Considering we will not be here most of the week, if i set my thermostat to maintain lets say, 12 dgrees C, is this going to be ok? Then when someone comes up for the weekend, they can just jack it up to 19C, this would bring on my propane.
2) New Tank start up
So the gas company never fired the furnace after installing tank, all i know is the tank is full. Whats involved in firing it up for the first time, do i just open up my shutoff valve, and measure my "wc at the burners? And then purge it until LP is present?
3) Automatic backup
If i have our system set for heat pump, and propane back up, if there is an issue with the heat pump, or the furnace, will the system automatically run the backup? Let say the furnace locks out due to a press. switch fault, will the heat pump automatically kick in and humm away? My biggest concern here is having a breakdown on my propane, and pipes freezing, as we just did 100,000$ of remodeling.
4) im thinking of possibly setting my switchover to -5C, any comments on this?
Also, the furnace is a 2 stage, should i run a jumper from w1 to w2 to maintain my 11"wc? or is LP ok to run on low fire?
10-28-2012, 11:33 PM #2
any input before i head out in 6 hours?
10-29-2012, 12:38 AM #3
also, my mistake, its a honeywell 3+2 8000
10-29-2012, 06:10 AM #4
The 8000 won't stage the backup so you'll have to let the timer on the board do it
It is recommended that neither the heat pump nor the 90+ furnace run with return temps below 60F. Not sure what that is in C talk.
There is no auto backup with the 8000. If it is above the changeover point and the HP fails, no heat.
10-29-2012, 07:33 AM #5
Go with ecobee so you have more control and understand how things operate under varying conditions.
Seems putting so much weight on propane will be expensive. And keeping it warmer will add buffer if power goes out.Which makes more sense to you?
CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%
DO THE NUMBERS! Step on a HOMESCALE.
What is comfort? Well, it AIN'T just TEMPERATURE!
Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.
10-30-2012, 11:52 PM #6
either way you are maintaining the 11" at the incoming side, manifold pressure is the only change, just like a natural gas unit.
make sure LP change has been done. I think this unit requires a gas valve, not a spring change!If Guns Kill People, Do Pencils Misspell Words?
10-31-2012, 10:40 PM #7Professional Member*
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use a honeywell iaq prestige with a wifi that way you can monitor the temp and operationThe governent can not give anything to someone that it has not first taken from someone else
11-01-2012, 05:45 AM #8
Switch to the IAQ or better. Then set the heat pump lock out at -15C and the furnace lock out to 5C, and set for a 2 degree droop. That way when no one is there and teh temp is set to 60, the furnace won't be running needlessly. HP should be able to maintain temp most of the time. Plus when someone gets there and turns the temp up, it will switch over to the furnace to recover, so your not waiting all night for the HP to recover. And then the next heat call will use the HP again.Contractor locator map
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