Baseboard heaters in VAV system

4 posts / 0 new
Last post

I've got a building that cools with shutoff VAV boxes and heats with
perimeter hydronic baseboard heaters.

When I'm setting up my system, do I specify hot water baseboard heaters
and leave the Zone Heat Source set to "Not Installed", or do I specify a
hot water loop for the Zone Heat Source, and eQuest knows to apply this
to the baseboard heaters and NOT the shutoff VAV boxes?

I currently have the Zone Heat Source as "Not Installed", but it appears
from my SS-R reports that there are hundreds of hours of underheating,
so something is not working correctly. I've had my hot water loop set
to snap, demand, and scheduled, so I think the loop is running

Thanks in advance!

James Hansen, PE, LEED AP

James Hansen's picture
Joined: 2011-09-30
Reputation: 200


In my opinion, baseboards act a little funny in eQUEST. This is how
I've made the scenario you describe work:

Under the Heating tab of your unit (Coil Cap/Control), restore the
default in the reheat entry so it is blank. Make sure the Hot Water
Loop is still enabled as the zone heating source though. Under the
Preheat/Baseboard tab, specify Baseboard Source as the Hot Water Loop.
You can change the default entries for the baseboards (pressure drop,
delta T, valve, etc.) if applicable. Then for each perimeter zone, go
into the heating tab and change the Baseboard control to Thermostatic if
it isn't already selected. I've had trouble getting the Outdoor Reset
selection to work and most of our projects have baseboards controlled by
thermostats anyway. You can also enter the capacity of the baseboards
for each zone or let the system self-size. This should work...if not
I'd be happy to look at the inp.


Andrew Craig, EIT,LEED AP

Andrew Craig2's picture
Joined: 2011-10-02
Reputation: 0

I was under the impression that eQUEST either doesn't size baseboards
correctly or at all. The few times I've had to use baseboards I have had
to solve the underheated hours by manually sizing the baseboard heaters at
the zone level. It's a pretty tedious process.

Robby Oylear

RobbyO's picture
Joined: 2010-11-03
Reputation: 0

Here's a nifty user expression to size baseboards based on BTU's per
unit area -- in this example 30 BTUs per SF:


Plug this into the 'Baseboards / Capacity' field for each zone with
baseboards (rightclick to get the context menu, select 'Edit/View User
Expression', etc.)


Brandon Nichols's picture
Joined: 2011-10-01
Reputation: 0