EDR Question for Trane #75 Unit ventilators ?Dangers of Not Changing All traps in One Day??

JUGHNE

There is a job with steam pouring out of cond pump vents.

I hope to have all materials arrive before starting the change out of all trap elements.

There are 5 EOM F&T's that need minor repiping.
These include 2 bucket traps that may be the main source of the steam in the return.
I feel confident to get these changed/repiped before having to have heat again overnight.

What is the thinking that failed smaller radiator traps could pass enough steam back to harm the new F&T's for one overnight operation of boiler??

The remaining 31 Hoffman 17C and 8C could be dealt with the next day.

I could adjust the pressure as low as possible....below 2 PSI.

Jamie Hall

Sounds like a good plan.

EBEBRATT-Ed

I agree with @Jamie Hall if you can identify any bad traps do those first

PC7060

@JUGHNE - when do you you expect to start the work? Is this the St. Anthony’s system in Columbus?

ChrisJ

JUGHNE said:

There is a job with steam pouring out of cond pump vents.

I hope to have all materials arrive before starting the change out of all trap elements.

There are 5 EOM F&T's that need minor repiping.
These include 2 bucket traps that may be the main source of the steam in the return.
I feel confident to get these changed/repiped before having to have heat again overnight.

What is the thinking that failed smaller radiator traps could pass enough steam back to harm the new F&T's for one overnight operation of boiler??

The remaining 31 Hoffman 17C and 8C could be dealt with the next day.

I could adjust the pressure as low as possible....below 2 PSI.

For my own understanding whats in an F&T that steam can harm?

JUGHNE

From reading and conversation with others, bad trap elements can pass steam to wreck newly installed elements.

F&T's have the thermostatic element and the float. Worst case scenarios are steam in the return entering the discharge line, meeting the water around the float and creating water hammer to beat up the float.
Also have read of the element being crushed by steam on the back side and vacuum on the front side.

This system has been running at 8 PSI for years. Plenty of steam out of pump vent pipe. Down to 4 PSI now. Would lower pressure for the overnight heating.
We could see single digits for that night.

I may be over cautious but this is a long distance job 150 miles away.

EBEBRATT-Ed

@JUGHNE

I think what your planning will be fine

JUGHNE

There was one trap cage back ordered for this project.
The trap is 3/4" Hoffman 8C.

The emitters are: (1950) Trane unit ventilators #75, coil #2 Cabinet is 15 x 32 x 60.
Print EDR is 298.2.

Is that EDR with the fan running or just convection?

There are 6 of these; one will be missing a trap element another has a broken TRV remote cap tube tstat.

For these problem children I was going to install an orifice in the inlet valve unions.

I have plenty of sizing info for orifices at various pressures.
I just need a good guess on the EDR as a coil.
They do not use the fan function.

I would size for 80% of the EDR.

mattmia2

You can always start smaller and see how much of the coil heats.

JUGHNE

The 298 EDR has to be with the fan running.
In another old school there are 99 EDR CI single pipe rads, these are huge as far as CI goes. They only heat 1/3 across with air vent TRV's.

So as a convector these must be 120 to 150.

Yes it is easy to up size, however I am only there this weekend. 150 mile/3hours away.