# Line voltage aquastat issue



## Dennis Alwon (May 9, 2009)

Please fill out your profile. Are you an electricians or just trying to get this thing to work in your own home?


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## Boonedocks2208 (Jan 19, 2019)

I am an IBEW Local 7 electrician and have been licensed for 13 years and am trying to make this work in my own home


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## Signal1 (Feb 10, 2016)

Assuming we're talking about a hydronic fan coils heater, 

You should put the aquastat on the return pipe, and wired to close on temp. rise, so the fan does not power up until the fan coil is hot. 

Question is, what is calling the heat zone? Is there a wall thermostat in the space?


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## Boonedocks2208 (Jan 19, 2019)

It is a hydronic heater and there is a wall 24v tstat that monitors the space. The aquastat I have is a Johnson a19d and it does not seem to have a temp rise setting. It seems to be either on or off no matter what the temp is set at.


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## Boonedocks2208 (Jan 19, 2019)

I wired it Y to R to close on increase but I’m not sure I’m setting it correctly and it doesnt turn on or off by temp


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## gpop (May 14, 2018)

You have to write out the steps like you are explaining this to a 5 years old.

I want the thermostat to turn the heater on 
i want the heater to heat the coils
i want the fan to run only when the coils are hot
I want the fan to shut off when the thermostat say the room is ok


Then you look over what you have written and look at the problems it may cause.

If you follow my logic you could argue that you payed to heat the loop and you are stopping the fan with a hot loop so you wasted money.

Once you have the list of steps it makes it easy to wire.


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## CoolWill (Jan 5, 2019)

The A19D is SPDT... stupid question, maybe, but is the fan wired to the right contact? Did you loosen the stop screw and set everything up by the instructions?


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## Boonedocks2208 (Jan 19, 2019)

I think my problem is I need a spst. I want the fan to turn on once temp is reached. I wired it so it closes once temp is reached but I don’t know how to set the set screw it doesn’t seem to matter how I wire it it won’t work unless I manually turn the aquastat


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## CoolWill (Jan 5, 2019)

1. Set dial to temperature at desired stop.
2. Remove the control cover.
3. Loosen the stop screw, slide the screw to the front of the control against the plastic step behind the dial, and tighten the screw (Figure 5). Sometimes an exact stop setting is not possible and the stop must be set to the closest step corresponding to the dial setting required.


Range Adjuster
A screwdriver slot with visible scale or screwdriver slot with concealed scale and solid cover are optional at no extra cost (quantity orders only). Models are available with field-convertible adjustment kit, which provides conversion to knob, concealed screwdriver slot or external screwdriver slot adjustment (Figure 6).


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## gpop (May 14, 2018)

Do you have the whole part number for the thermostat as the last few numbers tells you the factory set Differential. Also this isn't digital so it may be a little slow to react.


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## Boonedocks2208 (Jan 19, 2019)

A19DAC-1C

I think what’s confusing me is the set off. The set screw doesn’t hit anything when I set it to where I want it. I set my dial to 100°, that way when it gets that cool it shuts down. But there is no step to set the set screw to so the fan never turns on or off as the pex heats or cools


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## splatz (May 23, 2015)

Y-R closes on increase, I think that needs to be in series with the thermostat, assuming the thermostat is line voltage. 


```
L1-----thermostat-----Y-aquastat-R------fan------L2 
                   |--boiler----------------|
```
It's either Y-R or B-R, if Y-R is open when it's cool, that confirms that's the right contacts. 

Don't forget you have to adjust the setpoint


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## Boonedocks2208 (Jan 19, 2019)

It’s a 24v Tstat. Adjusting the setpoint is the only thing holding me up. I can’t figure out how to properly do it


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## Wirenuting (Sep 12, 2010)

This might sound silly but,

Is it a closed loop system with no automatic makeup?
Do you have a small pump to push the water?
Do you have a flow switch to kill the boiler if you spring a leak?

If you have automatic makeup water, do you have a Back-Flow preventer on it? (Not a check valve)

Oh ya,,, Welcome to ET


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## Wirenuting (Sep 12, 2010)

Boonedocks2208 said:


> It’s a 24v Tstat. Adjusting the setpoint is the only thing holding me up. I can’t figure out how to properly do it


I think 100 deg is kind of low. Those clamp ons take to long to come to tempature. We tried some several years ago and just went back to dry well or immersion sensors.


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## gpop (May 14, 2018)

A19DAC-1C 100 to 240F Temperature Range and Scale, 10 F (+/- 2.8 F) Differential, Visible Range Scale

If you set it to 100f you are at the limits for what it can do as it has a 10 degree Differential built into it. There is a pdf manual on line just google the part number.

Only adjustment it has is the dial to set the temp and a set point stop so someone doesn't accidentally set it past a safe number (not really needed in you situation)


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## Boonedocks2208 (Jan 19, 2019)

So, Y-R is open when cool. I have aquastat set at 140°. I set the stat to 80° so it would run for awhile to test. The pex is too hot to the touch and the fan has yet to kick on. It has been about 15 minutes since it has been set to 80°


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## Wirenuting (Sep 12, 2010)

Boonedocks2208 said:


> So, Y-R is open when cool. I have aquastat set at 140°. I set the stat to 80° so it would run for awhile to test. The pex is too hot to the touch and the fan has yet to kick on. It has been about 15 minutes since it has been set to 80°


Take your meter and read across the contacts.. See if they are opening and closing.


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## John Valdes (May 17, 2007)

Boonedocks2208 said:


> I am an IBEW Local 7 electrician and have been licensed for 13 years and am trying to make this work in my own home


Then fill out your profile. We don't help anyone until we know who they are and what they do.


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## John Valdes (May 17, 2007)

Welcome to Electrician Talk.
Thanks for taking the time to fill out your profile.


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## MechanicalDVR (Dec 29, 2007)

1. What do you have the aquastat mounted on?

2. What is the set point?

3. Can you hear the control make and break by turning the dial manually?

4. Have you tested the contacts with a meter?


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## Going_Commando (Oct 1, 2011)

Y and R should be the correct terminals for kicking a fan on for temp rise. Did you maybe mix up the wiring when you tied the aquastat in at the service switch box, or forget to turn the service switch back on? I hate to bring up these dumb questions, but we've all done dumb things like that before.


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## Wirenuting (Sep 12, 2010)

MechanicalDVR said:


> 4. Have you tested the contacts with a meter?


I asked that yesterday, he hasn't written since.
Maybe he used his Cheepo meter and burned his garage down?


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## MechanicalDVR (Dec 29, 2007)

Wirenuting said:


> I asked that yesterday, he hasn't written since.
> Maybe he used his Cheepo meter and burned his garage down?


With that aquastat the sensing bulb needs conductive paste to work well on copper so I can't imagine it working right on pex. They work much better with the well type model for his application.

When it's at set point R-Y is open, it has to be above set point to make.

I'd want to hear the contact make and break myself to know it does work.


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## Going_Commando (Oct 1, 2011)

MechanicalDVR said:


> With that aquastat the sensing bulb needs conductive paste to work well on copper so I can't imagine it working right on pex. They work much better with the well type model for his application.
> 
> When it's at set point R-Y is open, it has to be above set point to make.
> 
> I'd want to hear the contact make and break myself to know it does work.


I've always wondered if aquastats would work worth a crap on pex. We've never had a problem slapping honeywells on copper or black iron.


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## MechanicalDVR (Dec 29, 2007)

Going_Commando said:


> I've always wondered if aquastats would work worth a crap on pex. We've never had a problem slapping honeywells on copper or black iron.


Exactly! 

Never had any issues with Honeywell, even without using the paste that most guys never take out of the box. The sensor on the Honeywell has a nice size surface area to conduct heat.


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## just the cowboy (Sep 4, 2013)

Remove connections at aquastat and jump together, then open. Does the circuit work?


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## Boonedocks2208 (Jan 19, 2019)

All set. The temp setting I had it at was too low for the +/- 10°. Thanks for all the help


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## Signal1 (Feb 10, 2016)

Glad you worked it out.:thumbsup:


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