New Rheem Install Questions

[Jdeaton]

We just had a new Rheem dual fuel system Installed Friday. We live in Georgia.
Specifically:
• Heat Pump-RPRL-060JEC, 5 Ton, 16 SEER
• Furnace-RGRN 12ERAJS 120,000 BTU 95%
• Coil-RCFN-NM6042CC
• Thermostat was supposed to be a Rheem TST550CMMS but is currently a Honeywell TH8000.

We thought we were getting a fully communicating system. The Heat Pump is a “Prestige” series and the literature references “Comfort Control System” but the furnace is a “Classic Series” variable speed but not a “Prestige Series Serial Communicating Comfort Control 2” equipped furnace and according to the installers does not work with the Rheem TST550CMMS thermostat, thus we currently are using the Honeywell referenced above.
The contractor has admitted to his mistake and has ordered the proper furnace (hopefully a Model RGFG-12ERCM). As the communicating incompatibility was not noticed until after the old system was removed, they have temporally installed the new Classis Series furnace until the Prestige Series furnace arrives in 3 weeks. So, they are going to have to remove and reinstall the furnace twice. I’m glad they are going to make it right but I suspect this will be a money losing job for the HVAC contractor.

Questions:

The Honeywell TH8000 Thermostat is wired to a Honeywell C7089 outdoor sensor. I don’t know and can’t find where they mounted the outdoor sensor, but when the heat pump is running and providing heat the thermostat shows a much higher outdoor temp that is the actual outdoor ambient temp. You can watch the digital outdoor reading on the TH8000 rise steadily. For example, yesterday morning the ambient temp was in the low 40’s. The heat pump turned on and by the time it cycled off the TH8000 showed an outdoor temp of 79 degrees. Curiously, when the furnace provides the heat, the TH8000 continues to report the outdoor temp accurately. Is this normal or did they perhaps mount the outdoor sensor too close to the heat pump or might it be influenced by electrical interference when the heat pump is running?

The installers connected the condensate line to a vent/drain pipe rather than use the existing drain which drains from the attic to the outside of the house. Considering we are on a septic system, should I have them reroute the condensate to the old drain? I don’t want to over burden our septic system.

Lastly, are the benefits of a dual fuel “communicating system” worth the added expense? Hopefully yes.

Thanks for your expertise.

[second opinion]

We just had a new Rheem dual fuel system Installed Friday. We live in Georgia.
Specifically:
• Heat Pump-RPRL-060JEC, 5 Ton, 16 SEER
• Furnace-RGRN 12ERAJS 120,000 BTU 95%
• Coil-RCFN-NM6042CC
• Thermostat was supposed to be a Rheem TST550CMMS but is currently a Honeywell TH8000.

We thought we were getting a fully communicating system. The Heat Pump is a “Prestige” series and the literature references “Comfort Control System” but the furnace is a “Classic Series” variable speed but not a “Prestige Series Serial Communicating Comfort Control 2” equipped furnace and according to the installers does not work with the Rheem TST550CMMS thermostat, thus we currently are using the Honeywell referenced above.
The contractor has admitted to his mistake and has ordered the proper furnace (hopefully a Model RGFG-12ERCM). As the communicating incompatibility was not noticed until after the old system was removed, they have temporally installed the new Classis Series furnace until the Prestige Series furnace arrives in 3 weeks. So, they are going to have to remove and reinstall the furnace twice. I’m glad they are going to make it right but I suspect this will be a money losing job for the HVAC contractor.

Questions:

The Honeywell TH8000 Thermostat is wired to a Honeywell C7089 outdoor sensor. I don’t know and can’t find where they mounted the outdoor sensor, but when the heat pump is running and providing heat the thermostat shows a much higher outdoor temp that is the actual outdoor ambient temp. You can watch the digital outdoor reading on the TH8000 rise steadily. For example, yesterday morning the ambient temp was in the low 40’s. The heat pump turned on and by the time it cycled off the TH8000 showed an outdoor temp of 79 degrees. Curiously, when the furnace provides the heat, the TH8000 continues to report the outdoor temp accurately. Is this normal or did they perhaps mount the outdoor sensor too close to the heat pump or might it be influenced by electrical interference when the heat pump is running?

The installers connected the condensate line to a vent/drain pipe rather than use the existing drain which drains from the attic to the outside of the house. Considering we are on a septic system, should I have them reroute the condensate to the old drain? I don’t want to over burden our septic system.

Lastly, are the benefits of a dual fuel “communicating system” worth the added expense? Hopefully yes.

Thanks for your expertise.

they probably installed od stat in the condensing unit. Have them relocate to a location under eave or some location that will not see radiant only ambient temperature.

AC condensate should drain to outside.

On the dual fuel make sure the change over is set at design ballance point of your house.

[tigerdunes]

JDeaton

What size is your home?

This is replacement system?

It appears you will require Rheem's 550 series thermostat for full modulating functionality of the RGFG communicating furnace. It would be a mistake to have any other.

Outdoor sensor will be required with this thermostat.

Perhaps Baldllonie will see your thread. He has forgotten more about Rheem products than most people know.

IMO

http://www.rheem.com/documents/rgfg-specification-sheet

[Jdeaton]

JDeaton

What size is your home?

This is replacement system?

It appears you will require Rheem's 550 series thermostat for full modulating functionality of the RGFG communicating furnace. It would be a mistake to have any other.

Outdoor sensor will be required with this thermostat.

Perhaps Baldllonie will see your thread. He has forgotten more about Rheem products than most people know.

IMO

http://www.rheem.com/documents/rgfg-specification-sheet

This is a replacement system. The area is about 3240 SqFt. Ideally we would have two systems, one for the main level and one for the 750 SqFt second floor, but I figure we can do some zoning down the road and not have the expense of 3 separate systems. We already have an HVAC system for the finished basement. (We don't use the second story much anyway.) The original 14 year old system was a 10 SEER 5 ton AC unit with a 125,000 BTU 80% gas furnace. I worked OK, but not great, plus given the age and efficiency and fact we in we intend to retire here, I wanted an efficient system for the foreseeable future with the option to heat with either gas or electric depending on rates.

[tigerdunes]

Jdeaton

Well have you ever thought you might be oversized on that furnace?

The RGFG in the 100 KBTU model has a 5 ton rated blower. More is not better.

Just a thought.

IMO

[Jdeaton]

Jdeaton

Well have you ever thought you might be oversized on that furnace?

The RGFG in the 100 KBTU model has a 5 ton rated blower. More is not better.

Just a thought.

IMO

Would I be better off with a RGFG-10EZCM rated at 105,000 INPUT–MAXIMUM (BTU/HR) rather than the 120,000 BTU unit?
Would the smaller furnace work with the Coil Model#RCFN-HM6024CC which is already in place or would the smaller furnace require a physically smaller coil?

[tigerdunes]

Jdeaton

You should recheck the mdl number and size of that evap coil.

Here is what I found.

4519675 Active Systems RHEEM RPRL SERIES RHEEM MANUFACTURING COMPANY RPRL-060JEC * RCFM-H*6024 RGFG-10?ZCM? 57000 11.25 14.50 61500 9.05 40500

4519676 Active Systems RHEEM RPRL SERIES RHEEM MANUFACTURING COMPANY RPRL-060JEC * RCFM-H*6024 RGFG-12?RCM? 57000 11.40 14.50 61500 9.05 40500
*
I never want more BTUs than I need.

IMO
*
*

[BaldLoonie]

Most of the advantages of the communicating control on a Rheem is in the tech setup area. Operation can be fine tuned on the control as to blower speeds and other aspects that the the installer needs to address, assuming they do. It also gives reports on operating hours and modes and well as defrosts. Also, all error messages are sent to the control so the tech doesn't have to look at the board on the heat pump. Most HO's wouldn't care less about all that but someone who liked gadgets would get a kick out of what all it tells.

[Jdeaton]

Thanks to both Tigerdunes and BaldLoonie. I think you hit the nail on the head, I am not “most homeowners”. From studying Rheem’s website it became apparent to me certain components are intended to work with certain other components (in essence the “Prestige” communicating series furnace and heat pump along with the 550 thermostat are designed to work together as a system.) The mix and match that was installed works, but made me wonder if we were really getting the max benefit of a dual fuel 16 SEER compressor and a 90+ furnace. We plan on staying in this house for many years to come so even a small savings over time will add up. Nonetheless, I am still a neophyte in this field.

For example:

What does modulating function between 40% and 100% of total capacity mean? Does modulating mean infinitely variable? Does this term apply to the fan speed or BTU output? How is that different from multistage operating at a rate of 45%, 65%, and 100% of total capacity? Does any of this mean my house will be more comfortable, quieter, or cheaper to heat and cool? I hope it means all of the above.

[b26440510]

Does any of this mean my house will be more comfortable, quieter, or cheaper to heat and cool? I hope it means all of the above.

Newnan huh. Progressive by any chance?

I think modulating usually means more comfortable, not necessarily less expensive.

I have an RGJF with the TST550 series thermostat.

Any followup to non pro * members will need to take place in the 'General Discussion' forum per new site rules as of November 1.

[BaldLoonie]

It modulates in 5% increments from 40% to 100% as needs change. Customers love them. More comfy, more time on essentially inaudible lower fire. Won't save you gas over a single stage 95% though.

[udarrell]

It is extremely rare for a 5-Ton system to have adequate duct system & filter rack sizing; a 4 to 5-Ton system requires at least two large Return-Air filter grilles.

If it only has a 3.5 or 4-Ton duct system & airflow, well...
The entire duct system ought to always be checked for sizing & for air leakage before installing a super sized tonnage.

This post is to warn customers that high tonnage doesn't mean it is being "delivered to & from the rooms." It seldom is...