Do you think its the heat?

[Tommy1010]

I do hvac in a steel mill. Our caster section has a torch pulpit. There are 2 package 3 ton Trane units on the roof of the pulpit. Its a new pulpit and the units are less than a year old. the engineer of this project never bothered to ask for our opinion on anything regarding the sizing or location etc of the system to use. The roof of the booth is about 30' from the billet cooling bed. Even on a cool day, the ambient temp in that area reaches 140°f atleast. Inside the booth, when the a/cs arent on, you cant even touch the walls. The plastic covering on the ceiling lights all melts off...THAT HOT.

In less than 6 months we went through 3 blower motors, and 5 run caps.

All from wires melting.

When they ask me why this keeps happening??

Is it feasable to simply say..."Thats easy, just like I said from the start when you didnt ask me my opinion..Because ITS TOO F***** HOT UP THERE"

[crazzycajun]

We had one in a refinery same issues had to install water packs on condensor
problem went away (btw 140 was a cool day) and amazing enough a compressor lasted more than 2yrs go figure

[Tommy1010]

Sorry i didnt mention. its a water cooled package unit. Its the indoor blower motor that burns up.

[dlove]

I do hvac in a steel mill. Our caster section has a torch pulpit. There are 2 package 3 ton Trane units on the roof of the pulpit. Its a new pulpit and the units are less than a year old. the engineer of this project never bothered to ask for our opinion on anything regarding the sizing or location etc of the system to use. The roof of the booth is about 30' from the billet cooling bed. Even on a cool day, the ambient temp in that area reaches 140°f atleast. Inside the booth, when the a/cs arent on, you cant even touch the walls. The plastic covering on the ceiling lights all melts off...THAT HOT.

In less than 6 months we went through 3 blower motors, and 5 run caps.

All from wires melting.

When they ask me why this keeps happening??

Is it feasable to simply say..."Thats easy, just like I said from the start when you didnt ask me my opinion..Because ITS TOO F***** HOT UP THERE"

YUP...its hot..it amazes me when no one ask the onsite personal their opinion,
and that's what you get. did they duct the supply and return down? the other issue is they may have created stratification. I would hand it back over to the engineer who designed it and tell them it not working and make them deal with it. I hope they did their home work before they pop those up there!

[Tommy1010]

When I did a quick version of load calc for that room.....without even taking into account the people and equipment inside the room...just off the ambient temp outside in the mill...its asking for a 10ton system. Instead they put 2 seperate 3 ton units and ran it as a lead/lag set up.....??? and the duct work forget about it....

I told'em right from the start when i saw it...they shouldve put an indoor upright water cooled unit inside the room. The dirt in the air combined with the heat....is gonna be a nightmare....

Oh yeah this is the kicker....as hot as it is up there....the 2 units are friggin heat pumps AND back up electric heat?????? WUT THE F****

Motors are burning out and from the heat on units that you purchased with more heating than cooling BTUs....

NICE

[kdean1]

When the revolution comes the engineers will be the first ones up against the wall.

Wait, the lawyers are first, then the politicians, THEN the engineers.

[dlove]

When I did a quick version of load calc for that room.....without even taking into account the people and equipment inside the room...just off the ambient temp outside in the mill...its asking for a 10ton system. Instead they put 2 seperate 3 ton units and ran it as a lead/lag set up.....??? and the duct work forget about it....

I told'em right from the start when i saw it...they shouldve put an indoor upright water cooled unit inside the room. The dirt in the air combined with the heat....is gonna be a nightmare....

Oh yeah this is the kicker....as hot as it is up there....the 2 units are friggin heat pumps AND back up electric heat?????? WUT THE F****

Motors are burning out and from the heat on units that you purchased with more heating than cooling BTUs....

NICE

I hear ya but I cant imagine why they chose RTUs to cool or ventilate this area. There is no easy way to maintain comfort levels in the whole place under those conditions. Not knowing your set up, but spot exhausting where the most heat is produced would help, good rooftop exhaust with gravity intake dampers would help during the colder months. and when its hot outside a floor mounted unit water cooled or even a swamp cooler would of been better than what you have. good luck on this one

[Tommy1010]

Well how bout that..check the 1st post date of this thread...another cap just blew up.
Its 115°f on the rooftop!!!!!. Supply voltage 479v thats fine. Started blower motor back up with new cap, its rated at 1.7...drawing 3A ..???? Dam near double

On the last motor we changed out...you couldnt turn the shaft and it was hot as hell. As it cooled down it began to spin again,

Im goin with the heat and expansion theory on this as the culprit for all these cap and motor issues

. Any yays or nays?

[Chuck]

100% outdoor air units would be better than returning all that hot air!

Like someone said, exhaust the hot air, don't try to condition it.

[Tommy1010]

100% outdoor air units would be better than returning all that hot air!

Like someone said, exhaust the hot air, don't try to condition it.

or just simply put an indoor upright unit in the room like i said from day 1

[a/cpro]

100% outdoor air units would be better than returning all that hot air!

Like someone said, exhaust the hot air, don't try to condition it.

I have to agree there is know way you are going to condition that space.
I think a hydronic system would have been better for this situation.
A chilled water system would be much more forgiving.
Also an air handler with the motor externally mounted so it would not be xposed to those high. Temps.
Why were heat pumps used.?
Seems like you would never need heat.
Some of these engineers just don't get it they have never worked in the field and and every thing looks good on paper.but in real life it does not work.
Joe

[Bklyntek]

I've heard that in Europe, b4 you can apply for license asan engineer. You must work in the field for one or two years, that is with a recommendation from the employer, then you can take the certification(license). Seems like that's what we should here in the united states.

[sdt1104]

Engineers are like teenagers you don't have to tell them anything cause they already know it all.

[ControlsInMT]

Engineers are like teenagers you don't have to tell them anything cause they already know it all.

Engineers and weathermen..only two careers where you can be continually wrong and keep your job.

[Control Man]

And if it works , give them time they will RE ENGINEER it until it no longer does

[HVAC/R-Wizard]

115 degrees shouldn't cause immediate short term issues IMO, I come from induction melting and experienced the same ambient temps. I agree with the design issues but you have power issues causing those acute problems.

[HVAC/R-Wizard]

Well how bout that..check the 1st post date of this thread...another cap just blew up.
Its 115°f on the rooftop!!!!!. Supply voltage 479v thats fine. Started blower motor back up with new cap, its rated at 1.7...drawing 3A ..???? Dam near double

On the last motor we changed out...you couldnt turn the shaft and it was hot as hell. As it cooled down it began to spin again,

Im goin with the heat and expansion theory on this as the culprit for all these cap and motor issues

. Any yays or nays?

Verified 479 supply voltage, did you verify the motor requirements? Could this be a 575v packaged unit installed in a 460v application?