What transformer to use

cutter

I currently have a four zone hot water heating system and want to add two more zones and possibly one more to make seven. On a piece of Honeywell information I have it says a AT87A transformer will power up to five zone valves. What transformer would I need to power up seven. Two of the additional zones are in floor heat so I would not really need zone valves for them If I put in extra pumps. Would it hurt to have extra capacity on the transformer?



I am new to this site as you can tell. Is this site just for Oil, gas, and electric systems or is there people that know a little about connecting electrically an oil and a wood fired boiler? And maybe even some piping suggestion between the two?

Zman

What valves

What kind of zone valves?

Tinman

Answers

The best minds in the industry hang out here and can certainly address your above-mentioned questions.

SWEI

The figure Honeywell gives

Comes from their assumption of 320 mA per zone valve, which is what their V4043/8043 valves require.  Assuming you have those valves and you want to power them all off the same transformer, you would need one with at least 54 VA of capacity.  Most lines I know of offer 50VA and 75VA options.  You would need the 75VA model.



You could also add another 40VA transformer just for the new zones (assuming you don't have us kind of relay control which uses a single 24 VAC source.)

cutter

Honeywell V8043E 1020 and 1012 zone valves

When I asked about the transformer I thought I had put the zone valves that I was using in the message, guess not.