Parallel Zone Valves and Manual Operating a Zone Valve

I have two questions.

First is running zone valves in parallel and "tee"ing them together to larger diameter pipe. I have two 3/4" supplies that I wanted to tee feed a 1" water/air exchanger in my furnace. I'm not sure if I would need a check valves there. The reason i want to do this is I already had the 3/4" zones and don't feel like spending the money on 1" right now.

Second is manually operating a zone valve. I have a "Modine" style heater that will be in the garage. I "think" I could just open a ball valve manually and then turn on a switch to energize the modine fan and circulator and pump. The only time I'd be using it is when I'm there. It's a crude set up but I can't see why I would spend money on a thermostat, zone valve, and fan relay when I can just turn everything by hand.

You can do the above, but better options may exist. How many BTUH do each of your heaters require for full rated output? Do they actually need to achieve full rated output?

The best bet would be to place each heater on its own zone valve loop. If you can live with 30 degrees of temperature drop across each heater, you can deliver 60,000 BTUH to each unit without incurring velocity noise. 40,000 BTUH for 20 degrees of temperature drop.

Be careful operating zone valves manually, some need to be powered off to operate in manual to prevent damage.

coaledsweat wrote:Be careful operating zone valves manually, some need to be powered off to operate in manual to prevent damage.

The "zone valve" would be a ball valve. Power on circulator and modine fan, open ball valve until the room is warm.

Why don't you just buy a line voltage thermostat and wire everything to that? What are they, $20?

What kind of boiler is supplying the heat? Will it deliver sufficient sustainable output BTUH for your two users? What are the BTUH demands of the two users? What is the heat loss requirement of the areas being heated by the two users? How many annual HDD's does your area receive on average?

If each user requires the kind of GPM flow that demands 1" pipe, why not take your pipe up to 1" immediately after the zone valve and run a single line instead of paralleling two lines to achieve the requisite flow? A 3/4" zone valve probably has a similar pressure drop across its very short length as would one to at most a couple of 1" elbows.

If you are going to power the pump from 2 different sources make sure the feed at the panel comes from the same side of the panel box. I believe that if its fed from the other leg you can have a problem as the phases of each leg are out 180 deg. I think....

waldo lemieux wrote:If you are going to power the pump from 2 different sources make sure the feed at the panel comes from the same side of the panel box. I believe that if its fed from the other leg you can have a problem as the phases of each leg are out 180 deg. I think....

I believe this is accurate.

Scottscoaled wrote:Why don't you just buy a line voltage thermostat and wire everything to that? What are they, $20?

I didn't realize how inexpensive there were. Thanks

lsayre wrote:What kind of boiler is supplying the heat? Will it deliver sufficient sustainable output BTUH for your two users? What are the BTUH demands of the two users? What is the heat loss requirement of the areas being heated by the two users? How many annual HDD's does your area receive on average?

The house is currently sized for a 110K BTU furnace. Boiler puts out appr 150K. The Modine style heater is rated for 50K BTU (aftermarket heater and I'm not sure I believe the rated output) and will only ran once or twice a week. I could probably just run a 3/4" to it and be ok with it.

The water/air exchanger is rated at 80K. My heating needs right now is less than that as I am still heating most of my home with a hand-fed until I use that up.

lsayre wrote: If each user requires the kind of GPM flow that demands 1" pipe, why not take your pipe up to 1" immediately after the zone valve and run a single line instead of paralleling two lines to achieve the requisite flow? A 3/4" zone valve probably has a similar pressure drop across its very short length as would one to at most a couple of 1" elbows.

One 3/4" would probably be but I won't know until I run delta T tests across my plenum. I would like the second 3/4" zone available if need it in the future when I run out of nut coal. I still have more calculations to perform but I won't know until I get this plumbed in. :/

Scottscoaled wrote:Why don't you just buy a line voltage thermostat and wire everything to that? What are they, $20?

I didn't realize how inexpensive there were. Thanks

lsayre wrote:What kind of boiler is supplying the heat? Will it deliver sufficient sustainable output BTUH for your two users? What are the BTUH demands of the two users? What is the heat loss requirement of the areas being heated by the two users? How many annual HDD's does your area receive on average?

The house is currently sized for a 110K BTU furnace. Boiler puts out appr 150K. The Modine style heater is rated for 50K BTU (aftermarket heater and I'm not sure I believe the rated output) and will only ran once or twice a week. I could probably just run a 3/4" to it and be ok with it.

The water/air exchanger is rated at 80K. My heating needs right now is less than that as I am still heating most of my home with a hand-fed until I use that up.

lsayre wrote: If each user requires the kind of GPM flow that demands 1" pipe, why not take your pipe up to 1" immediately after the zone valve and run a single line instead of paralleling two lines to achieve the requisite flow? A 3/4" zone valve probably has a similar pressure drop across its very short length as would one to at most a couple of 1" elbows.

One 3/4" would probably be but I won't know until I run delta T tests across my plenum. I would like the second 3/4" zone available if need it in the future when I run out of nut coal. I still have more calculations to perform but I won't know until I get this plumbed in. :/

waldo lemieux wrote:If you are going to power the pump from 2 different sources make sure the feed at the panel comes from the same side of the panel box. I believe that if its fed from the other leg you can have a problem as the phases of each leg are out 180 deg. I think....

The circulator is isolated from second feed so I'm good there. thanks

You guys need to stop giving out electrical advice. What you just told him can be soooooo wrong. Do not hook the pump up to different sources. Bad, Bad, Bad!!!!!!! Or the same side of the panel. NO! NO! NO!


Scoby, I take it you will be using two pumps or will have some way to turn your circulator on for the"manual zone that you haven't shared?

Scott, why cant you have the pump fed from two sources as long as they are the same leg? How about hooking up the pump with a three way switch??? As I understand it there is only one pump that is turned on or off by the aquastat or a zone control device...

I presume that the issue becomes one of two different breakers feeding a single user. Two hot 120 lines feeding at the same time and you have 240, and with a 120 rated neutral to overheat and fry no less (even if the user can survive it). But at least the phases will be aligned. I merely confirmed the phase alignment with no further thinking. Pull power from both sources through the same breaker, and I believe Scottscoaled's astute observation should be satisfied. That is, unless I'm missing something else here (which is highly possible).