[Equest-users] [equest-users]

[Jon Evans]

W. Peter,

Check your zone airflows - if too low, it will take quite a bit of heat from the coil to change the space temperature. 1 cfm/SF of supply air is typical for many building types and spaces with standard ventilation requirements.

Check your reheat deltaT - this delta plus your preheat coil in your air handler need to be higher than your space setpoint

Check your zone supply air temperature - I think eQuest defaults to 95; I would bump this up to 105.

If you have simplified the zoning of the building you may want to break these problem spaces up into smaller zones.

You can also override your zone coil capacities, but should coordinate this with the mechanical designer to ensure that your modeling is realistic (for example you have simplified and combined several zones; make sure that the coil capacity is at least the summation of all these zones).

Good luck.


Jon Evans, PE, LEED AP



Sustainable Engineering Group LLC

431 Charmany Drive Suite 102

Madison, WI 53719



Tel: (608) 231 9664 x 13

Fax: (608) 231 9665

E-mail: jevans at sustaineng.com

Web: www.sustaineng.com

________________________________
From: W. Peter Anderson [mailto:panderson at jpengineer.com]
Sent: Thursday, June 25, 2009 9:00 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] [equest-users]

Greetings-
I have set up PVAV systems with hot water coils.  I am getting error messages (See Below) for each of my systems.  On the LS-S reports, heating capacity for unit and zones is zero, but I do have hot water coils and a boiler loop, etc.

See below,
Thansk,
W. Peter Anderson, P.E
JP Engineering
41 Mechanic Street
Windsor, CT 06095
Ph: 860/688-5223
Fax: 860/688-5269


**WARNING**********************************************************************

ZONE EL1 NE Perim Zn (G.NE2)

might have insufficient heating capability.

Check that the SYSTEM or ZONE HEATING-CAPACITY plus this

ZONEs BASEBOARD-RATING is adequate to maintain the ZONE

specified DESIGN-HEAT-T for the calculated peak ZONE load

(see LS-A or LS-B for the ZONE peak load.)

SYSTEM HVAC-1

which supplies the above listed ZONE, has a design heating

coil exit temperature, HEAT-SET-T,(plus any zone reheat)

below its MAX-SUPPLY-T or the ZONE DESIGN-HEAT-T, which

might account for the insufficient heating capability.

**WARNING**********************************************************************

ZONE EL4 East Perim Zn (G.E2)

might have insufficient heating capability.

Check that the SYSTEM or ZONE HEATING-CAPACITY plus this

ZONEs BASEBOARD-RATING is adequate to maintain the ZONE

specified DESIGN-HEAT-T for the calculated peak ZONE load

(see LS-A or LS-B for the ZONE peak load.)

SYSTEM HVAC-1

which supplies the above listed ZONE, has a design heating

coil exit temperature, HEAT-SET-T,(plus any zone reheat)

below its MAX-SUPPLY-T or the ZONE DESIGN-HEAT-T, which

might account for the insufficient heating capability.

**WARNING**********************************************************************

PREHEAT/HEATING-CAPACITY in SYSTEM HVAC-1

is too low to provide the requested supply temperature for

the calculated mixed air temperature using total ZONE loads

(on LS-A/B) and SYSTEM design parameters, plus outside air

conditions (on LS-C), and specified capacities & air flows.

Requested temperature is 55.00 calculated is -3.14

Check HEATING-CAPACITY, HEAT-SET-T, PRE-HEAT-T, MAX-SUPPLY-T,

DESIGN-HEAT-T, and ZONE loads for consistency.

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