ReplyNot really, have you got pics of the return piping, maybe get the O and M that came with the coil. That would point you, on how it was to be installed.
Regular Guest
I got a Air handler that has a steam coil mounted horizontally and was told the coil is not draining.
I have witness it in action. after a few hours of operation the discharge temp drops from 130 down to 80.
the steam pressure and heating valve remain the same 5-10 psi and valve wide open.
the only way the operator can get it to work again is to "drain it" he closes the hand valve then drains the circuit at the strainer before the steam trap.
We had a few contractors look at it, the even replaced the trap and strainer.
Was told the only way to get this to ever work is to angle the coil inside the air handler to help it drain.
Odd yes?
Professional Member*
Not really, have you got pics of the return piping, maybe get the O and M that came with the coil. That would point you, on how it was to be installed.
Regular Guest
The air handler is over 30 years old so no O&M's.
I was told the coil was replaced in 2001 and again in 2010.
Unfortunately, I got conflicting reports as to when the problem started.
One old timer says he never had the problem while he was there(before and after the 2010 coil was replaced)
and all he did was bleed the water from a drip leg each morning, before the main steam trap. (might be BS). all the traps were replaced and the problem continues.
The new operator says for the last 5 years or so, when he comes in each day at 4 am, he finds the discharge temp down to 80 (normal is 120). He then closes the hand valve then drains the air handler at the strainer shown in the picture. soon as he does that, the air temp quickly raises to 120+
So, to some up what I know...
this unit needs to be drained each morning at the strainer leaving the air handler to get it to work again. unless your this other dude who claims he was told to only drain the drip leg hand valve before the air handler each day regardless of performance. and he never has any performance issues. again, i think this guy is wrong, the main steam trap before this air handler is brand new and it did not help.
all traps and strainers have been replace all piping checked for restrictions.
Regular Guest
I think they installed the wrong coil in 2010. maybe this coil was design to be mounted vertically? or maybe was not meant for steam??
Regular Guest
I found a picture of what I think is the exact coil someone installed in our air handler. it sure looks like a vertical install only coil to my untrained eye.
Professional Member*
Is a model number and mfg on that coil you could find or better the original paperwork. If the strainer valve is just cracked open a little does it work then?
Regular Guest
Buford, I don't have any info on this coil. I am looking into it. I have not tried cracking the strainer slightly. I can only tell you the strainer and trap you see in this picture both were replaced by a boiler company that claimed would fix this problem and it did not help.
Membership Chair/ARP Committee / Professional Member*
If the coil was going to drain that water drop to the trap would handle it easily. So, as the coil clearly retains condensate, either the coil is the wrong design or it is installed badly incorrectly.
Who made the replacement coil? What does their spec say in regard to application?
Is the coil level?
Is there anyway to lower the header end / raise the return-bend end?
BTW: anyone who said: "I never had a problem" while describing his actions to deal with the problem is clearly FOS.
If manual draining at the strainer makes the coil heat then I would install a steam rated electric solenoid on the drain line, hard-pipe the outlet of the solenoid, control the solenoid valve with an interval timer relay, and leave conspicuous notes in regard to it's operation. I'd start with ten seconds every eight hours and then adjust by the empirical method.
PHM
------
Originally Posted by alikair
The air handler is over 30 years old so no O&M's.
I was told the coil was replaced in 2001 and again in 2010.
Unfortunately, I got conflicting reports as to when the problem started.
One old timer says he never had the problem while he was there(before and after the 2010 coil was replaced)
and all he did was bleed the water from a drip leg each morning, before the main steam trap. (might be BS). all the traps were replaced and the problem continues.
The new operator says for the last 5 years or so, when he comes in each day at 4 am, he finds the discharge temp down to 80 (normal is 120). He then closes the hand valve then drains the air handler at the strainer shown in the picture. soon as he does that, the air temp quickly raises to 120+
So, to some up what I know...
this unit needs to be drained each morning at the strainer leaving the air handler to get it to work again. unless your this other dude who claims he was told to only drain the drip leg hand valve before the air handler each day regardless of performance. and he never has any performance issues. again, i think this guy is wrong, the main steam trap before this air handler is brand new and it did not help.
all traps and strainers have been replace all piping checked for restrictions.
PHM
--------
When faced with the choice between changing one's mind, and proving that there is no need to do so, most tend to get busy on the proof.
Professional Member*
I have seen that coil in that pic, always in a vertical application, not to say it will not work but i would throw a level on it. I would think also it would slope towards the front. The label may be on the copper header as in the pic. What is the steam supply pressure and has it been raised over the original settings? Not knowing what else the steam is heating, maybe someone turned up the pressure thinking that would fix it.
Regular Guest
We tried adjusting the pressures a bit, did not help.
I got the manufacturers PDF on that type of coil. it says it can be used both horizontal as well as vertical... but in that PDF, the diagram shows a slight change in the design of the header.
the horizontal diagram shows the outlet slightly below the inlet.
The PDF also states the airflow direction needs to be known when ordering a coil.
I think someone ordered a coil and didn't spec for down airflow operation. If this is the case, I dont know if we can go back to the original installer and make them put the right coil in. that should have been caught back in 2010. I think my predecessor failed to give a ****e.
Membership Chair/ARP Committee / Professional Member*
If you were to look at a vertical-only coil - the tubes come out of the tube sheet and connect to the header straight. This is not a problem because the condensate then falls down the vertical header. If you were to look at a horizontal coil the tubes come out of the tube sheet and make a 45-90º turn down before connecting to the header.
A horizontal coil will typically work in either configuration - but it is more expensive to make so often the unknowing or uncaring use a vertical-only coil improperly.
You wrote: "the horizontal diagram shows the outlet slightly below the inlet"
And now you know why that is. <g>
PHM
------
PHM
--------
When faced with the choice between changing one's mind, and proving that there is no need to do so, most tend to get busy on the proof.
Membership Chair/ARP Committee / Professional Member*
You could approach this with higher pressure - looking for higher velocity because that's what you are getting by opening the drain. The trap is too efficient to allow that - and it seems like a poor approach anyway.
Are you really looking to butt heads and start a bunch of contentious-ness? Or are you more interested in this system heating the space automatically? Going after an installer for something like this, especially after four years, seems like it could be a real uphill battle to me. And for what real good in the end?
My suggestion would be to do the minimum to make this coil heat adequately and move on to more important matters. As I suggested earlier.
PHM
--------
When faced with the choice between changing one's mind, and proving that there is no need to do so, most tend to get busy on the proof.
Professional Member
Can you even get a down flow horizontal steam coil in a counter flow configuration with the inlet and outlet on the same side?
Seems to me that it's not possible but maybe I'm missing something.
Looking at the images, it appears that the outlet is below the inlet. Is this the case?
Anyway to increase the pitch of the unit &/or coil toward the outlet?
What is the device mounted hi on the condensate line?
Last edited by ESokoloff; 11-15-2014 at 01:13 PM. Reason: Addition of hi mounted device.
Professional Member*
What is the device mounted hi on the condensate line? Air vent from the last co that said they could fix it or vac breaker.
Regular Guest
we got a quote a few years ago to angle the coil. they wanted 7 grand
Regular Guest
its a air vent
Regular Guest
We tried the higher pressure route. did not help. I dont like the idea of butting heads but I dont think the contractor who installed the wrong part should get away with it either. We are a large company with many buildings. They need to make things right or at least give us a good price to fix this problem.
Regular Guest
yes you can get one. here is the link to the manufacture PDF
http://www.armstronginternational.co...steamcoils.pdf
Professional Member
Did the piping remain the same over these 30 years?
How high is the condensate return from the lowest point off the outlet trap?
It takes 1psi to raise 2.31' of water so perhaps insuffectiant lift is a factor?
Are there other air handlers with simular installations or is this one unique?
According to this http://www.armstronginternational.co...ing-principles
"When installing steam traps, what is the ideal distance between the heat exchanger and the trap outlet?
12-36 inches (0.3-0.9 m)."
Professional Member
Are you sure you have a Centifeed Coil (Type C or P) as opposed to a conventional return bend type?
Posting Permissions
