Heating coil contrlols problem
Heating coil contrlols problem
(OP)
I have a heating coil in an air handling unit that is struggling to maintain room set point without over heating the room. If the control valve is only slightly open say 10% the top of the coil is hot and the bottom is cold. Only when the control valve gets to about 40% open does the entire coil heat up and then it is all of a sudden roasting...... it is giving hugh problems...The poor BMS is struggling to maintain the set ponit and the BMS company is blaming the coil... What you think?? Looks like the modulating valve could be over sized too but this has nothing to do with the coil issue mentioned surely.





RE: Heating coil contrlols problem
Possible to reduce loop temperature in the system? Lower MWT would have the effect of reducing the 'size' of the heating coil.
RE: Heating coil contrlols problem
I agree with your comments thanks, but why is the top of the coil hot and the bottom cold when low flow thro the coil? should it not be even thro out..>?
RE: Heating coil contrlols problem
If it is a lot of outside air that is going over the coil then it might not be oversized. Depending on your climate the heat needed might vary a lot between summer and winter.
You could make a circuit with an extra pump running 100% flow over the coil to have even warming under all circumstances, even if the control valve is at 10%. The control valve will regulate the flow going to the coil loop.
RE: Heating coil contrlols problem
It would likely work best if the hottest water entered low on the discharge side of the coil (counter flow).
The pumped coil will work as well assuming the coil is piped and vented properly.
RE: Heating coil contrlols problem
RE: Heating coil contrlols problem
RE: Heating coil contrlols problem
RE: Heating coil contrlols problem
Be cautious with respect to the RH requirement.
I mean, are these beans "wet" when they come in and will they loose moisture which you have to remove in order to maintain 65% or do the beans absorb moisture which you have to add in the process ?!?
Be sure the building envelope can handle the 65% indoor-RH.
If (points off) the inner walls/construction get below dewpoint condensation will occur.
(Depends of course on what climate you're in)
RE: Heating coil contrlols problem
Oops: ignore my post above, it ended up in the wrong topic...
RE: Heating coil contrlols problem
RE: Heating coil contrlols problem
RE: Heating coil contrlols problem
RE: Heating coil contrlols problem
RE: Heating coil contrlols problem