New Bosch System, Wrong T-stat Provided?
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New Bosch System, Wrong T-stat Provided?
My parents got a new Bosch system installed as follows:
BOVB20 variable capacity heat pump
BGH96 2-stage propane furnace
Pro1 Technologies T855 t-statI thought all these variable capacity inverter driven heat pump/AC units required a communicating t-stat. Is that true? This T855 t-stat can only do 3 heating and 2 cooling. It seems like they wont get full control of everything and most of the staging will just be timer based.
Does anyone know what the correct t-stat should be for this setup?
Thanks.
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The Bosch units don’t use communicating controls. If the furnace is capable of adjusting blower speeds, the stat they have is fine and set up properly. The blower speed is reduced if the stat is on low and ramps up if there’s a call for high cool. Then the Bosch senses refrigerant conditions and adjusts it’s compressor accordingly. So it isn’t time based but senses the load and ramps the compressor up or down accordingly.
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Originally Posted by BaldLoonie 
The Bosch units don’t use communicating controls. If the furnace is capable of adjusting blower speeds, the stat they have is fine and set up properly. The blower speed is reduced if the stat is on low and ramps up if there’s a call for high cool. Then the Bosch senses refrigerant conditions and adjusts it’s compressor accordingly. So it isn’t time based but senses the load and ramps the compressor up or down accordingly.
Interesting. So it sounds like there isn’t any way to control humidity levels with this setup.
What about balance point control? How is that done?
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Originally Posted by badtlc 
Interesting. So it sounds like there isn’t any way to control humidity levels with this setup.
What about balance point control? How is that done?
A properly sized unit controls RH.
Balance point is specific to your house, its location and several other factors.
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Originally Posted by pecmsg 
A properly sized unit controls RH.
Of course but with a varying capacity system, if the CFMs can’t vary with it, then latent cooling capability can’t be set properly even for a properly sized system. But there is no “size” with variable capacity to pick good CFM settings.
Originally Posted by pecmsg 
Balance point is specific to your house, its location and several other factors.
yes it is. And it needs to be adjustable within the control system to to pick the correct balance point of the system/location. How is that modified or controlled in such a setup when the t-stat doesnt do it and heat pump has no outside thermometer?
badtlc
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