ECN Forum
Posted By: Attic Rat Zone valves.... - 12/03/05 01:56 AM
... Hi gang,... Seasons Greetings to you all,... (now comes the hard part)...
I have been "chosen" by my builder to do the wiring for 5 zone valves all are 4 wire type on a hot water furnace system with a hydronic system going to the air handlers..it's a forced air system and.. "I DON'T DO ZONE VALVES!!",...the HVAC guy,or the plumber is usually the one who does this.. I really have somewhat of an idea of what I gotta do,..but I'm really fuzzy.. Can I get a hand here??? Puleeze!!
Thanx,
Russ
Posted By: JoeTestingEngr Re: Zone valves.... - 12/03/05 02:22 AM
2 of the leads are usually connected to 24VAC through the individual thermostats and drive the valves open when a given zone calls for heat. The other 2 wires go to a switch that closes when a valve opens. These all tend to get wired in parallel so that any or all zones calling for heat, will start the circulating pump.
Joe
Posted By: Kelley Re: Zone valves.... - 12/03/05 02:46 AM
check out the taco site or hunnewell site for diagrams.
Kelley
Posted By: Electricmanscott Re: Zone valves.... - 12/03/05 02:48 AM
Kelly has the right idea. Also the zone valves ususally come with paperwork that has diagrams.
Posted By: trevman Re: Zone valves.... - 12/03/05 05:31 AM
2 wires are for 24v and the other 2 wires are for a signal usually 0- 10 v or 4 -20 ma
to drive the valve open or closed, unless the valve has a spring return. the valves with the switch in them i think is used for sprinkler tamper valves
Posted By: hbiss Re: Zone valves.... - 12/03/05 04:44 PM
Geeze trevman, listen to what the others are saying before you give bad information.

Two leads are the motor that opens the valve, remove the power and a spring closes it. The other two leads are from a switch that closes when the valve is fully open.

As was said, usually all the switches are connected in parallel and then to what normally would be the thermostat terminals (T&T or R,W) on the boiler. When any zone valve opens it's switch closes and starts the boiler and circulator.

The motor leads from each valve need to go to it's respective air handler. The controls there need to provide the 24 volts to it when the thermostat calls for heat. This can be done in a number of ways and might even require an additional relay and transformer on your part. Depends on what's there. let us know.

-Hal

[This message has been edited by hbiss (edited 12-03-2005).]
Posted By: SparksNmore Re: Zone valves.... - 12/03/05 05:16 PM
Not all zone valves are spring loaded to close.
Some valves use a spdt TS that sends power to the valve to open AND sends power to the valve to close it.

{edit}
Sorry I thought the discussion was about "water valves, not forced air air duct zone valves.
I should have read the original post better and/or remained a lurker. [Linked Image]

[This message has been edited by SparksNmore (edited 12-03-2005).]
Posted By: trevman Re: Zone valves.... - 12/03/05 07:23 PM
hal,as far as i know the boiler starts on outside air temp and return water temp.not all valves have spring return, some have 24v at the valve all the time and use a signal provided through a electronic controller or t-stat to tell the valve which way to go.
r is one side of 24v w is for heating and i have never heard of t&t. i think you may be the one with bad info. i highly doubt that a end switch on a valve is going to start the boiler, unless maybe the boiler is in florida where they dont need heat.
Posted By: hbiss Re: Zone valves.... - 12/03/05 07:34 PM
Well, I'm not going to say that what you talk about doesn't exist but you won't likely see something like that used in this application. Why confuse things?

Any of the current and usual residential and light commercial hydronic zone valves you encounter are from Taco, B&G or Honeywell and all operate as I described. Yellow leads are the motor, reds are the end switch. Power= open with a spring return to closed. Switch closes when the valve is open.

-Hal
Posted By: trevman Re: Zone valves.... - 12/03/05 07:42 PM
maybe in canada things are different.ive never heard or taco or b&g. the valves we use the most here are made by a co. called belimo and sometimes wirsbo. the best bet is to check the instructions for the valve like previously said by others. i was just trying to generate some discussion on the topic.
Posted By: hbiss Re: Zone valves.... - 12/03/05 07:51 PM
hal,as far as i know the boiler starts on outside air temp and return water temp.

I'm not going to get into a long dialog with you but around here in the north east boilers are either maintained temperature or cold start. Most are the latter to save energy and will only run when a thermostat calls for heat and will cycle on the high limit aquastat until the thermostats are satisfied. There are some high end boilers and controllers that will modulate the water temperature based on the outside temperature but most operate the same way.

Not all valves have spring return, some have 24v at the valve all the time and use a signal provided through a electronic controller or t-stat to tell the valve which way to go.

Sure and there are DDC (direct digital control)systems and networked systems with (GASP!) CAT5 wiring also but that't not what the original post is about now is it.

r is one side of 24v w is for heating and i have never heard of t&t. i think you may be the one with bad info. i highly doubt that a end switch on a valve is going to start the boiler, unless maybe the boiler is in florida where they dont need heat.

The end switches control the boiler the same way as a low voltage thermostat would with only one zone.

-Hal
Posted By: iwire Re: Zone valves.... - 12/03/05 07:54 PM
Don't worry Trevman, it is easy to forget that different ares use different equipment.

In this area I have not seen any residential zone valves that use either 0- 10 v or 4 -20 ma. The ones used here are crude full open or full closed valves using 24 volts.

Welcome to the Forum.

Bob
Posted By: JoeTestingEngr Re: Zone valves.... - 12/03/05 08:06 PM
I think Hal gave a more detailed explanation of what I was describing. I differ a little with him in that I think you usually just start moving fluids with the switches on the zone valves. I'm used to seeing the boiler doing its own thing, running between its low and high temperature set points. Thermal mass, delta Ts, flow rates, # of zones calling for heat, all that good stuff, will eventually cause the boiler to kick in at its low temperature setpoint.

I should've mentioned that we're talking low voltage, current limited here. The switches tend to connect to a module that contains its own 24 volt transformer and the relay/contactor that controls the circulating pump.

Any air handlers/heat exchangers at the far end might well have their own high and low temperature set points (or just 1 set point with a dead band or differential.) This way, you don't start blowing cold air around or stop the fan while the coils are still hot.
Joe
Posted By: JoeTestingEngr Re: Zone valves.... - 12/03/05 08:50 PM
Trevman's description reminds me of only one system that I've dealt with. This Transportation Office had only one loop to heat the whole building. A heat exchanger in the back used modutrols to control recirc. and make-up air dampers. These modutrols have pots in them that reference the wiper to the vane position. Another Modutrol, on the water side, controls a proportional valve to control how much water goes through the heating coils Vs. around them, before going to the rest of the loop. This valve also has position feedback via a pot in its Modutrol.
I doubt that this is what's in Attic's basement.
Joe
Posted By: hbiss Re: Zone valves.... - 12/03/05 09:13 PM
In this area I have not seen any residential zone valves that use either 0- 10 v or 4 -20 ma.

They are modulating zone valves uses with a building control system usually in a commercial application. They may be open, closed or anything in between depending on what the controller wants. Instead of a switch there is a potentiometer that gives position feedback to the controller- 4 to 20ma loop current depending on the position.

-Hal
Posted By: trevman Re: Zone valves.... - 12/03/05 09:14 PM
is this how a residetial boiler with a fan works? t stat calls for heat, valve opens ,end switch makes&starts boiler& pump,high limit senses coil is hot and starts the fan. also would there be a seperate coil in the duct for each zone and therefore a limit or temp sensor at each coil to start the fan? Is this what the attic rat is talking about?
Posted By: iwire Re: Zone valves.... - 12/03/05 09:20 PM
Hal thanks but I am aware of 0- 10 v or 4 -20 ma controls. [Linked Image]

I just have never seen those systems used for standard residential zone valves.

Bob
Posted By: hbiss Re: Zone valves.... - 12/03/05 09:56 PM
is this how a residetial boiler with a fan works?...

There can be differences but with most hydro-air systems the stat calls for heat, the zone valve opens starting the circulator and boiler. The fan can start at the same time or it can be controlled by an aquastat on the return water line from the coil. When it gets hot it turns the fan on. This just keeps the fan from blowing cold air until the coil heats up.

also would there be a seperate coil in the duct for each zone and therefore a limit or temp sensor at each coil to start the fan?

There is a separate fan coil (air handler) unit for each zone with it's own associated ducting. Like I said, the fan can be started as soon as the stat calls for heat or they can use an aquastat on the water line.

I have seen systems that are further zoned with dampers in the ducts and a controller that interfaces the T stats and dampers then operates the zone valve as above.

Keep in mind also that each air handler usually has an air conditioning coil also so it is used for both heating and AC. This further complicates the fan control and the way it is wired to the T stat.

I should add that the T stat is wired to the air handler which in turn controls the zone valve and outdoor AC unit, except when additional dampers are used.

-Hal

[This message has been edited by hbiss (edited 12-03-2005).]
Posted By: Alan Belson Re: Zone valves.... - 12/03/05 10:02 PM
Russ,
These valves usually come with a mnfrs. data sheet giving the options for various circuit control layouts, with wire colors to stepper motor and relay feeds and outputs shown.
Usually, the valve is opened by a signal from a programmer, time clock, switch or programmable thermostat. Upon being fully open, a relay in the valve closes, ( and often there is a NC set of contacts available too), which gives an independant signal which you can use to fire up a boiler or furnace, run water circulators etc.. This independance of signal is vital if you have multiple zone heating or domestic hot-water heating + central heating etc, because you don't want to backfeed other programmers or thermostats upstream.
I have used this sequence;
Programmer signal to valve, and to the water circulator. That's safe, the water is circulating when the valve is open. Relevant valve relay signal taken to the boiler [furnace] firing sequence through a thermostat, so when the boiler/furnace shuts down, [ie. satisfied], the circulator continues to run using residual heat.
I know this sounds obvious, but in complex set-ups, make a sketch of the circuit showing the wire colors and identifying the valves etc., and keep it for reference. You'll be back to fit replacements in the future.
And if an old dolt like me can do it, anyone can!

Alan
Posted By: trevman Re: Zone valves.... - 12/03/05 10:05 PM
do you mean each zone has its own fan and its own set of coils or would there be just one fan and possibly damper controls?
Posted By: hbiss Re: Zone valves.... - 12/04/05 12:01 AM
Usually each zone will have it's own air handler. If suppose you want to put a thermostat in each room, an air handler for each can get expensive so the best thing to do there is one air handler for an area and dampers for each room in the duct work controlled by the thermostats.

Dampers work the same way as zone valves. T stat opens the damper, end switch on the damper controls the air handler, air handler controls the zone valve which controls the boiler and circulator.

Talk about Rube Goldberg!

-Hal
Posted By: Attic Rat Re: Zone valves.... - 12/04/05 12:03 AM
... A BIG THANK YOU to all who replied!! [Linked Image] [Linked Image]
You see, I was just testing you all,..(yeah,right [Linked Image] [Linked Image])

Hal, you're right,the zone valves are spring loaded Honeywell brand, 4 wire type..and they're being used to control a hydronic/forced air system, the stat calls for heat, the zone valve opens starting the circulator and boiler.I figured it all out this morning,..I first installed (2)120v X 24v,40va xfrmers,because I was told that you can't put more than (3) zone valves on a 40va xfrmer.Then I tied one leg of each of the yellow motor leads of the (3) zone valves together,and brought it to the first transformer.The remaining xfrmer terminal wire to the other end of t-stat(s).I then spliced the remaining yellow wire to it's corresponding thermostat leg,..(well,I will,once the HVAC guy runs them,the house is completely done,sheet-rocked,painted,and all,and the HVAC guy forgot to run his stat lines..go figure..)I took one red leg each from the end switch in the zone valve and tied them together,making a pair of spliced wires,and connected them to my T/T terminals inside the boiler control box.I did the same for my other (2) zone valves,wired to the second xfrmer.I also had to wire the low water cut-off,so I wired it so that the leg from my service switch goes thru the low water cut-off,then proceeds to the L1,L2 terminals of the boiler's control box so it shuts everything off if there's a problem..(that was at the behest of the plumber). I "think" it'll work,..if not,I'll be back here asking dopey questions again.. Thanx again,guys!!
Russ




[This message has been edited by Attic Rat (edited 12-03-2005).]
Posted By: Attic Rat Re: Zone valves.... - 12/04/05 01:04 AM
... Oh,and Hal,... here's a REAL Rube Goldberg: [Linked Image from geocities.com]

[Linked Image] [Linked Image] [Linked Image] [Linked Image]
Russ
Posted By: Matt Barrett Re: Zone valves.... - 12/04/05 01:36 AM
I like playing with boiler controls…

In my house I used a Tekmar 260 boiler controller to control three zones of heat and one indirect fired water heater all with individual circulators.

I have a 20 amp contactor that I use as a safety loop, a low water cut-off and Fireomatic thermal switch over the system hold the contactor closed.

A variable speed circulator on a bypass line keeps the return water at 135 minimum.

[Linked Image]

Edited to shrink image.

[This message has been edited by Roger (edited 12-04-2005).]
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