Converting to Gas - Need expert advice on 2 (so far) parts

fred9

1. Forced hot air furnace, 2550 sq ft colonial in CT. Two zone heating (EWC controls) was installed when house was built in 1992. I'm getting multiple quotes and the 2nd guy says I should replace the two zone dampers. He says they could fail and recommends they be replaced during the conversion. I asked if this was like being told to replace a car's water pump when replacing the timing belt. So, do Zone dampers fail and, if so, would it be "smart" to replace them during the conversion?
2. Re DHW - the first two companies have led with Tankless. I have read here and other places that they require more maintenance and can cost more (still true today??) and monthly savings are not that large. We raised to kids here with a Boch 32e with only few "no hot water" screams and now there are just two of us. I can live with a 90% eff tank and don't need 96+ from a tankless. Is my conclusion misguided or misinformed?

I know price is not to be discussed here but when I balked at Navien Tankless, the reply was a AO Smoth GPHE-50 for more $$$?

I welcome any comments. I also want to thank Aaron in Maine for suggesting I go with LP if the NG is not here before heating season due to the cracked heat exchanger on current oil fired furnace.

Thanks

Bob Bona_4

Agree with the damper topic. EWC makes great stuff, but your vintage dampers and control board are obsolete. You can replace now or replace as components fail. The dampers today are a huge improvement with less moving parts. The control today can allow a "master" thermostat at each zone vs. The fussy slave/master arrangement that used to be the norm. Have to have at least 4 conductors at each stat location though. Sometimes the slave stat had the minimum 3 wire run only.

Your call on the DHW. Tank less will allow you to abandon the chimney and introduce combustion air to the unit vs the typical can HWH that's vented into a chimney. What's the new furnace venting? Direct out of house? What was the plan for the chimney? Discontinue?

fred9

Thanks Bob for confirming it makes sense to replace the zone dampers.
The current plan is to not use the chimney for either furnace or DHW.

Bob Bona_4

Wait until you see the simplicity of the modern ones. They changed them about 14 years ago. Liking the indicator led's, can tell damper position at a glance.

good plan with nixing the chimney. Where are you in CT?

fred9

Simsbury

Thanks again, Bob for your advice and info.

Bob Bona_4

I'm Norwalk. You're welcome

John Mills_5

Are you getting a 2 stage furnace? They are perfect for zoning and avoiding overheating when you aren't at 100% of your zones calling. You would want a zone panel that will stage the furnace based on need. We set them up that with 1 zone calling, only fires on low. With both calling they get high. Cheap panels don't do this but a good one will.

fred9

John,
No hard quotes with model numbers yet other than the one DHW. I had not thought about 2 stage but now will look into it. I have been asking for ECM motor and "high efficiency". Thanks for the education.

Aaron_in_Maine

Glad I could help you out. I would recommend a two stage furnace as well because you have a zoned system. I personally like tankless water heaters. I have a Rinnai RL75 in my house for six years now with no issues on LP. I use 150 gallons of propane a year for hot water and I also have my grill hooked up to it. When I worked for the propane company we used to estimate 250 to 300 gallons a year for tank type water heaters don't know how true that number is because I never had one just throwing that out there.

fred9

Thank you Aaron.

fred9

Question is about wiring needed for thermostats.
I am a homeowner. I now have natural gas and tomorrow the HVAC contractor will be installing:

1. Trane XV95, 2 stage variable speed furnace.
   
2. HZ322 two stage zone panel
   
3. 2 FocusPro 5000 thermostats
   
4. 2 new replacement zone dampers
   
   When they were here months ago to work up the quote they said I needed five wires to each thermostat. I do have 8 wires to the main one and 5 to the current "slave".
   My concern is that when I read the installation instructions for the Thermostat it indicates 8 wires are needed for "2H/2C system". My AC is only one stage so maybe I only need 7 wires?
   
   For 1H/1C System, only 5 wires are needed.
   My question is - Will I lose the benefit of the 2 zone heating if the thermostats are set up for 1H/1C?
   If so, the good news is that the 5 wire one is on the first floor so re-wiring might not be too difficult.
   Thank you for any input.
   

njtommy

I would image it depends on how they set up the zone controller. I've set them up before using on a single stage heat/ cool to each t-stats. If only one zone calls it will only need 1 stage of heat. If both zones call at the same time the zone controller will turn 2nd stage of heat and or cooling.

Also if pulling wires is an issue they can upgrade your t-stats to Honeywell Red Link and you will only have to wire 2 wire just to power t-stat. It will just communicate wirelessly.

fred9

Ok Tommy. That makes sense and makes me feel better but I think I will question them tomorrow anyway.

Thanks for your help.

John Mills_5

Not sure the 322 will stage your 2 stage furnace well. It appears it has 2 ways to go to high fire. Thermostat calling for it or a timer in the panel calling for it. So it can go to high with 1 zone calling which can be noisy. It will downstage if the air gets too hot. That's good. But a 432 panel will let you choose to stage by % of zones calling. If you have 2 zones, it will require both to open before you get high. Did that at the boss's house, worked out well.

fred9

Happy to report i was wrong. Today my contractor was able to set up two stage heating with 5 wires. I don't have a common (so batteries are essential) and I don't have 2 stage AC so I don't need 2nd stage "contractor". I was also wrong here saying the 'stat manual called for 8 wires ( 7 combining R and Rc)
John, Thanks for your info. I didn't know enough to research control panels. I'm just happy to have NG and hope that installing an efficient 2 stage furnace will eventually pay off financially.