Retrofitting an HVAC zoning system

[bbruck]

I've been looking for a way to retrofit my house for a zoned heating system. Due to the fact that my basement is finished and the ductwork was not designed for multiple zones, my heating contractor says it would cost $5k to install zones. I've been looking for an inexpensive motorized vent system that I could integrate into my home automation system, and I'm wondering if you think the following would be possible:

Springfield precision instruments makes a product called Vent Miser, which is basically a motorized register with a removable timer, powered by AAA batteries. It sells for $29 on Amazon (http://www.amazon.com/Vent-Miser-91664-Programmable-Saving-10-Inches/dp/B000MWBPKA), significantly cheaper than other motorized vents I've found.

I'm thinking perpahs I could run an appropriately rated wire from each damper through the plenum to a central controller that would integrate to my HA system. Then I could remove the timer from the vent miser and either (a) send the on/off signal through the wire, bypassing the timer feature but still powering the servo from the timer batteries; or ) send the power through the wire, completely bypassing the timer.

I know either of these would mean modifying the device and in the (a) scenario, taking it apart to modify it - which naturally voids the warranty - but I'm wondering if you think this might be feasible?

 

[icellama21]

There are a number of factors that go into zoning an existing heating system. You should consult with a HVAC specialist.

The most important is to make sure you always have adequate airflow through your heat exchanger and fan. If the airflow is too small, the evaporator coils can freeze, heat exchanger can crack, fan motor can burn out, etc. You can also have a lot of noise from the added pressure in the ducts.

You also need some kind of intelligent zone controller. What do you do if one zone calls for heating, and another calls for cooling? When to open/close dampers? Do you need custom purge cycles, etc. An intelligent controller can handle this, but when you go on vacation do you want your home automation controller/computer running your heating? A dedicated zone control panel is far more reliable and quite cheap.

As for dampers, just about anything you find CAN work. Their failure modes are simple, stuck open, stuck closed, stuck in between. If you've set up adequate bypass to protect your heat exchanger and have a zone controller panel that monitors plenum temps, no big deal. But once again, do you want to deal with the headache, what if it breaks while you are on vacation?

I'd recommend the honeywell retrofit dampers(if you have round supply ducts). They are easy to install and not very expensive. Plus they are industrial quality.
http://dticorp.com/catalog/honeywell-rrd7-...per-p-4526.html.

 

[drozwood90]

I've been looking for a way to retrofit my house for a zoned heating system. Due to the fact that my basement is finished and the ductwork was not designed for multiple zones, my heating contractor says it would cost $5k to install zones. I've been looking for an inexpensive motorized vent system that I could integrate into my home automation system, and I'm wondering if you think the following would be possible:

Springfield precision instruments makes a product called Vent Miser, which is basically a motorized register with a removable timer, powered by AAA batteries. It sells for $29 on Amazon (http://www.amazon.com/Vent-Miser-91664-Programmable-Saving-10-Inches/dp/B000MWBPKA), significantly cheaper than other motorized vents I've found.

I'm thinking perpahs I could run an appropriately rated wire from each damper through the plenum to a central controller that would integrate to my HA system. Then I could remove the timer from the vent miser and either (a) send the on/off signal through the wire, bypassing the timer feature but still powering the servo from the timer batteries; or ) send the power through the wire, completely bypassing the timer.

I know either of these would mean modifying the device and in the (a) scenario, taking it apart to modify it - which naturally voids the warranty - but I'm wondering if you think this might be feasible?

In a way, that's what I am doing. I have 30 of those. I'm trying to remember where I bought them, as I got them for $12.99 each. I'm planing on using cat5 to power them. I was trying to figure out if I could run the wire (somehow) through the heating duct...but apparently that's a no no...even though it's LV, my insurance company told me that even if a fire is NOT related to the wire...the wire can be seen as a intentional path the fire could take...so I'm not allowed to do that...luckily before the walls went up, I had run a ton of cat 5...some of which was put into the wall just for this reason...
I just thought it would be nicer to run it through the duct so that there is no wire mess (WAF ++).

As for HOW (B) is how I am going to do it. I took the timer apart. It's not overly complicated. So, I'm just going to do B.

--Dan

 

[rosenqui]

Has anyone tried the Flex Dampers from RetroZone for a retrofit zoned HVAC system? It seems like they solve the big problem of installing dampers in a house with finished walls / ceilings / floors. You'd still need to run a wire to the zone thermostat or find a wireless thermostat that works, but that seems like less of a hurdle than an extensive damper retrofit.

I've got a non-zoned Carrier Infinity ICS system, and with the Canadian Government's 15% home renovation tax credit I've been thinking of converting it to a zoned system, but the prospect of tearing up the floors or ceilings to install dampers has been holding me back.