[Milk man]

KMC series reset control
NC damper actuator
NC PE switch
KMC RCC-1112 reversing relay
KMC RCC-1108 high pressure selector relay
Barber Colman THR-1001 DA thermostat

This is a new box and I was told the factory set up the controls. I went to do the start up and it was heating regardless of the set point. I teed in some tubing, that was not connected, that went to B on the high pressure selector relay. It is teed in with stat B and T on the reset control.

The box will cool when demanded but will not heat. Can someone explain the operation of the reversing relay? A piping drawing would be good to have to verify it is piped correctly. Any advise is appreciated.

 

[orion242]

This is a new box and I was told the factory set up the controls.

What year is it?!?! Insert face palm here.

All that garbage has cost far more than just about any standalone electronic control on the market which would be far less hassle to setup & test.

 

[Milk man]

I thought so. But I'm not the decider. I just need to make it work.

 

[BBeerme]

A properly adjusted and working reversing relay will reverse the signal.

A 3 psig input will result in a 15 psig output, and vice versa. A nine pound input will result in a nine pound output.

 

[Milk man]

I think it is not piped correctly. I think I need to pipe from stat B to reversing relay S. Also tee into this line and go to high pressure selector switch S2. Also tee into the stat B line and go to the PE switch.

Then pipe reversing relay B to high pressure selector switch S1.

Then pipe high pressure selector switch B to T on the reset control.

I drew out a couple diagrams. One heat and one cool. In Lynn's personal world it will work. We will see if it does.

Thank you.

 

[hvac69]

The reversing the relay I would expect would need to be used to feed the PE since the thermostat is DA and the PE will need to be RA so the heat fails off on loss of air pressure. No idea why a hi press selector would be needed for a VAV. What brand VAV?

 

[BBeerme]

Maybe to set up a minimum position on an application where they always want some airflow. A couple of years ago I set up something like that for a conference room, but other than that, never seen a high select relay on a VAV.

He might be looking at a VariTrane hot deck / cold deck.

I think they were normally open 3-8 psig, so you needed the reversing relay to make one NO and the other NC. No velocity controllers. At 9 psig, they'd both be closed.

The reversing the relay I would expect would need to be used to feed the PE since the thermostat is DA and the PE will need to be RA so the heat fails off on loss of air pressure. No idea why a hi press selector would be needed for a VAV. What brand VAV?

 

[Milk man]

It is a price box

 

[Milk man]

it is a single duct. I think they are called a VVT. No blower.

 

[BBeerme]

Yikes.

 

[71CHOPS]

Get all the manuals and spec sheets for each individual component, then draw out the piping. Compare it to the perceived sequence of operation.....usually the issue pops out at you.

 

[Milk man]

This is what I did over the weekend. I have a plan for next visit to the box. I think it is currently piped wrong.

 

[Milk man]

Update. One of the other senior techs went with me. We had to calibrate the stat. Then he adjusted the high and low airflow. It seems to be working now.
I still think there are piping issues involving the reversing relay and high pressure selector switch.
Thanks for the help.

 

[billcontrols]

Check out
https://www.priceindustries.com/con...sets/literature/submittals/control-diagrams/single-duct---control-sequences.pdf

Sequence 1011

and...

https://www.priceindustries.com/con...assets/literature/service-installation-manuals/section f/servi_f-11_spv8000.pdf

Google is a fountain of Information.

Could also check out KMC for the controller data...

 

[BBeerme]

Was either you or the senior tech able to figure out why the high pressure select switch is being used?

Update. One of the other senior techs went with me. We had to calibrate the stat. Then he adjusted the high and low airflow. It seems to be working now.
I still think there are piping issues involving the reversing relay and high pressure selector switch.
Thanks for the help.

 

[orion242]

Better yet. Do they other similar working setups on-site you can just look at.

How much has this single VAV cost to date?

 

[Milk man]

Thank you. I did several searches, but never looked at the Price site. I just looked at the links and will look closer when I have more time.

 

[Milk man]

Not yet, I have a thought but wanted to check the drawings first.

 

[Milk man]

Better yet. Do they other similar working setups on-site you can just look at.

How much has this single VAV cost to date?

No other boxes like this. Cost?? How about training to reduce such costs. We have a a couple pneumatic buildings, but I'm not proficient. Or there could have been a piping diagram included, or left with the box. It would of avoided a lot of confusion.