Air Handler Valve Actuator

[jingoism]

Hello all.

I recently accepted a job where we are running a closed loop chilled water system for our Air Handlers, and I have a question as all my past exp. has been with residential air cooled systems.

They are using mechanical actuators on the chilled water supply going into the air handlers, and have had some trouble since I started with them not being positioned correctly. So we have a guy go up and take the actuator off and start trying to adjust it according to the temperature.

Question I have is there any way to tell for certain if the valve is all the way closed, or all the way open?

[jcrank]

We are going to need more information like what type of actuator and valve brand model. There is allot of different types of actuators out there.

[jingoism]

Yah I figured you might, but thought there might be some kind of universal way to do this that I was not aware of.

Currently at home and have no idea so I will update you Mon.

[Shophound]

Hello all.

I recently accepted a job where we are running a closed loop chilled water system for our Air Handlers, and I have a question as all my past exp. has been with residential air cooled systems.

They are using mechanical actuators on the chilled water supply going into the air handlers, and have had some trouble since I started with them not being positioned correctly. So we have a guy go up and take the actuator off and start trying to adjust it according to the temperature.

Question I have is there any way to tell for certain if the valve is all the way closed, or all the way open?

Where are you working now, Jingo? Refresh my mind...you're the guy who once worked in a hotel or something, right?

Are there Pete's plugs on the chilled water lines going in and out of each air handler? Pete's plugs are a fitting where a portable pressure gauge can be inserted and removed. If you have two Pete's plugs and two gauges, insert one in each and then cycle the valve through its maximum travel. Note the pressure differential as you cycle the valve...also, hold a screwdriver blade up against the valve body and put the handle of the screwdriver up against your ear...it's not a bad way to know when the water stops flowing.

As for these actuators, are they pneumatic or motor driven via DDC (direct digital control)? If DDC, and you're having problems with them being positioned correctly, it could involve a combination of determining the valve's closed position, driving the actuator closed with it not attached to the valve stem, and then clamping down the actuator to the stem with the valve confirmed closed. After that it may take adjusting the PID loop to make it hold setpoint.

On many chilled water valves with a protruding stem, there is a groove on the end of the stem. When the groove is parallel with the pipe, the valve is open. When the groove is perpendicular to the pipe, the valve is closed.

[jingoism]

Working for another hotel actually... except now I am not actually working maintenance but actually as a plant operator for the chillers and boilers.

Thanks for the advice also! They are electrically actuated valves connected to Johnson Controls to answer that question.

Pete's plugs... hmm.. have to check on that one.

[Shophound]

Working for another hotel actually... except now I am not actually working maintenance but actually as a plant operator for the chillers and boilers.

Thanks for the advice also! They are electrically actuated valves connected to Johnson Controls to answer that question.

Pete's plugs... hmm.. have to check on that one.

Hey! Another central plant operator on board. Not a whole lot of us here. I'm at an art museum in Fort Worth running a plant solo. Three chillers, two boilers, three towers, ten air handlers, two cold storage systems, 130 or so VAV boxes, Johnson Controls Metasys. Hardly a dull day goes by. :D

Which hotel you at? Does it have the older Metasys PMI or the newer extended architecture UI? Either way if the actuator is being controlled by an AHU or UNT controller it can be tuned through HVAC-PRO either manually or with PRAC tuning.

[jingoism]

Popped you an email. :)

Seems we are working on some very similar equipment ... now I know who to ask all the questions too. :D

[clayb1]

Hello,

Typically and air handler on a chilled water system has a three-way valve. The valve modulates to provide full or partial flow through the coil. Typically the valves are installed with the actuator up. The "bottom" of the valve then is normally open. One of the other ports is normally closed, and the last is common (normally applies to pnuematic with spring return, but the construction of the valve is the same). If the stem is up, usually the flow is to the N.O. port, and if down, to the N.C. port. Honeywell valves are marked A, B, & AB where AB is common. Others have arrows. I installed a Johnson last year, & I don't remember how they are identified, but this should help. So I'm not sure f the "Pete’s plug" term either; however there test ports for a pocket thermometer. Small hex caps, with O-rings inside. You can safely remove the cap and insert your thermometer inside the pipe into the chilled water (I spit on mine to lube it for easier insertion).

Once you determine the supply temp., you can measure the return temp. If the return is the same you know which is position bypassing the coil.

Hope this helps.

I've been a Stationary Operator for years and am just now venturing out into "regular" units, e.g. package, splits and Heat pumps

[atmosphere]

Working for another hotel actually... except now I am not actually working maintenance but actually as a plant operator for the chillers and boilers.

Thanks for the advice also! They are electrically actuated valves connected to Johnson Controls to answer that question.

Pete's plugs... hmm.. have to check on that one.

Pete did not invent the Pete's Plugs.

These handy lil' fits can measure both temp and pressure.

The name is sort of a jazz version of "P" (pressure) and "T" (temperature), which led to PT or "Petey" shortened to "Pete".

I have also heard them called "Peach" plugs.:o

And Good Luck.

[Shophound]

Hello,

Typically and air handler on a chilled water system has a three-way valve. The valve modulates to provide full or partial flow through the coil. Typically the valves are installed with the actuator up. The "bottom" of the valve then is normally open. One of the other ports is normally closed, and the last is common (normally applies to pnuematic with spring return, but the construction of the valve is the same). If the stem is up, usually the flow is to the N.O. port, and if down, to the N.C. port. Honeywell valves are marked A, B, & AB where AB is common. Others have arrows.
Once you determine the supply temp., you can measure the return temp. If the return is the same you know which is position bypassing the coil.

Hope this helps.

I've been a Stationary Operator for years and am just now venturing out into "regular" units, e.g. package, splits and Heat pumps

Welcome to the boards, Clay. As you well know, central plants can be complex, but even operating one my respect still holds for package and split systems, and heat pumps. I've worked on plenty of them and have seen many suffer from poor installation and service techniques. So I guess I'm saying that as you move into these systems, you won't find yourself not technically challenged and you won't be bored. :)


I installed a Johnson last year, & I don't remember how they are identified, but this should help. So I'm not sure f the "Pete’s plug" term either; however there test ports for a pocket thermometer. Small hex caps, with O-rings inside. You can safely remove the cap and insert your thermometer inside the pipe into the chilled water (I spit on mine to lube it for easier insertion).

Don't let hvaclover read that quote...it's wide open for some smart innuendo comments. :D

Seriously, you described by what I meant by "Pete's plugs" well. They have either the hex caps or a cap that resembles what you'd find on a Schrader valve.

My own facility has mainly two way butterfly chilled water valves and uses a bypass at the plant to maintain chilled water delta P setpoint across the largest air handler. I do have three-way valves on the cold storage units that are marked and behave as you've described (A, B, AB). I also have two way valves that are rising stem (not threaded), but on the actuator itself there is a mark indicating relative valve position.

With central plants, always more than one way to skin a cat, it seems.

[clayb1]

I've worked on plenty of them and have seen many suffer from poor installation and service techniques. So I guess I'm saying that as you move into these systems, you won't find yourself not technically challenged and you won't be bored. :)

I know my I'm a rookie status, I am humbled every day:o




Don't let hvaclover read that quote...it's wide open for some smart innuendo comments.

Oh well, sometime I lead with my chin; if it's useful and correct, I learn. If it's mean spirited and or overly critical,,, well I used to feel better by pulling others down. I've mostly let that unproductive trait go. So, I just let them go.
Thanks for your reply/welcome

[Shophound]

Oh well, sometime I lead with my chin; if it's useful and correct, I learn. If it's mean spirited and or overly critical,,, well I used to feel better by pulling others down. I've mostly let that unproductive trait go. So, I just let them go.
Thanks for your reply/welcome

I know what you mean about that...one who seeks to pull himself up by pushing others down only sinks further into the mud, I've learned. Not a happy way to be. When you help others up you also get a boost. Much better way to live. :cool: