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rockycmt
12-05-2007, 11:33 AM
I currently have 3 zones on my hot water system. These valves run at 24volts from what I have read. I was wondering if I can add 2 more zones to the system? Is there a limit to how many zones the 24 volt transformer can support/power?

jadnashua
12-05-2007, 11:55 AM
Absolutely...the transformer may need to be updated. It should be marked with VA rating, which will indicate how much power it can supply. Each valve will also have a required value. Add up the load, and then compare with what's available. The transformers aren't often particularly expensive or hard to replace, if required. Yours could have enough capacity, but you need to check to be sure. The valve's requirement should be in their spec sheet.

rockycmt
12-05-2007, 12:40 PM
I will do that, Thanks for the info.

rockycmt
12-05-2007, 01:07 PM
Here are the specs on a new 24 volt transformer.

http://pexsupply.com/product_dtl.asp?pID=1740&cID=282&brand=Honeywell
Voltage: 750 mV
Connection Type: Spade Terminals
Lead Length (in.): 35 in.
Lead Length (mm): 889 mm
Open Circuit Output (mV): 600 mV to 750 mV
Resistance: 2.89 ohm
Temperature Ratings (F): Hot Junction 1400 F
Temperature Ratings (C): Hot Junction 760 C
Temperature Ratings (F): Cold Junction 780 F
Temperature Ratings (C): Cold Junction 416 C
Includes: push-in clip
Used With: Q314, Q324, Q327, Q377, Q379, Q382 Pilot Burners
Tradeline Value: Tradeline
Ref: Honeywell.com

What is the actual numbers I need to compare? I do not see a VA reference.

jadnashua
12-05-2007, 01:56 PM
Don't think that is designed for things like zone valves; more like a specific component in the ignition circuit. 750mV spec and the temperature ratings seem to be the telling ones. You need something like this: http://www.pexsupply.com/product_dtl.asp?pID=4559&brand=Honeywell&cID=282

Chris75
12-05-2007, 02:25 PM
I currently have 3 zones on my hot water system. These valves run at 24volts from what I have read. I was wondering if I can add 2 more zones to the system? Is there a limit to how many zones the 24 volt transformer can support/power?


If you look at the wattage of the zone valve and the VA of the transformer you can figure out hot many a 40VA transformer will hold, But you can always use as many transformers as needed...

I really like these Taco Controls, they simplfy the wiring and neaten it up quite nice, take a look... You can get a 6-zone board, which comes with 2 transformers built right in...


http://www.pexheat.com/catalog/images/taco/ZoneValveControl.jpg

rockycmt
12-06-2007, 09:25 AM
Ok, So just to finish this off..

The total watage of the valves (Simply add them all up) can not exceed the VA of the transformer?

jadnashua
12-06-2007, 10:53 AM
As I understand it, yes. power=volts x amps.