excessive underheating

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Good Day eQuest-users,

I apologize if anyone can help me in the following use, there is a VAV with reheat system, DX cooling and Hot Water Reheat. The Hot Water reheat is supplied by a boiler. The building is one floor with perimeter and core zones.

The following issue cause excessive unmet load hours in heating, I figure out that changing Heat/Rehat: Hot Water delta F from 30 F to 20 F reduce unmet load hours but cooling capacity is increased tremendously, also the following warning is maintained.

Please, any of you have go ahead with the following warning?

**WARNING**********************************************************************
ZONE EL1 WSW Zone (fG.z1)
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 S1 Sys (PVAVS)
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.

ZONE EL1 WSW Zone (fG.z1) has a THERMOSTAT-TYPE
of REVERSE-ACTION, which, when added to the issues listed
in the messages above, will cause excessive underheating.

Thank you!

SUMAC
Dante Garcia, LEED AP BD+C
Tel: +511.253.5355 Anexo 16 (Lima, Per?)
Cel: +51.989.685.769 (Lima, Per?)

Dante Garcia's picture
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Joined: 2013-05-22
Reputation: 0

Hi Dante:

It always helps to include your .INP and .PD2 files on your email to this forum, so experts can help you.

Without seeing anything more, I would increase the deadband in your deadband thermostat from 2 to 4 06 6 DegF. I would also set the the COOL-CONTROL to WARMEST.

Otherwise, please attach your files. And let us know which version of eQuest you are using.

John R. Aulbach, PE
Los Angeles CA USA

Good Day eQuest-users,

I apologize if anyone can help me in the following use, there is a VAV with reheat system, DX cooling and Hot Water Reheat. The Hot Water reheat is supplied by a boiler. The building is one floor with perimeter and core zones.

The following issue cause excessive unmet load hours in heating, I figure out that changing Heat/Rehat: Hot Water delta F from 30 F to 20 F reduce unmet load hours but cooling capacity is increased tremendously, also the following warning is maintained.

Please, any of you have go ahead with the following warning?

**WARNING**********************************************************************
ZONE EL1 WSW Zone (fG.z1)
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 S1 Sys (PVAVS)
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.

ZONE EL1 WSW Zone (fG.z1) has a THERMOSTAT-TYPE
of REVERSE-ACTION, which, when added to the issues listed
in the messages above, will cause excessive underheating.

Thank you!

SUMAC
Dante Garcia, LEED AP BD+C
Tel: +511.253.5355 Anexo 16 (Lima, Per?)
Cel: +51.989.685.769 (Lima, Per?)

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John Aulbach's picture
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Joined: 2011-09-30
Reputation: 1

Hi John,

Here in Attached INP and PD2 files,

I have tried your recommendations before without success, eQuest version is 3-65.

Thank you!

SUMAC
Dante Garcia, LEED AP BD+C | Analista LEED Energ?a
Tel: +511.253.5355 Anexo 16 (Lima, Per?)
Cel: +51.989.685.769 (Lima, Per?)
Tel: +593.4.600.0613 (Guayaquil, Ecuador)
Tel: + 571.3151985 (Bogot?, Colombia)
Tel: +1.773.857.7906 (Chicago, USA)
dgarcia at sumacinc.com
www.sumacinc.com

De: John Aulbach [mailto:jra_sac at yahoo.com]
Enviado el: viernes, 07 de noviembre de 2014 06:31 p.m.
Para: Dante Garcia; equest-users at lists.onebuilding.org
Asunto: Re: [Equest-users] excessive underheating

Hi Dante:

It always helps to include your .INP and .PD2 files on your email to this forum, so experts can help you.

Without seeing anything more, I would increase the deadband in your deadband thermostat from 2 to 4 06 6 DegF. I would also set the the COOL-CONTROL to WARMEST.

Otherwise, please attach your files. And let us know which version of eQuest you are using.

John R. Aulbach, PE
Los Angeles CA USA

Good Day eQuest-users,

I apologize if anyone can help me in the following use, there is a VAV with reheat system, DX cooling and Hot Water Reheat. The Hot Water reheat is supplied by a boiler. The building is one floor with perimeter and core zones.

The following issue cause excessive unmet load hours in heating, I figure out that changing Heat/Rehat: Hot Water delta F from 30 F to 20 F reduce unmet load hours but cooling capacity is increased tremendously, also the following warning is maintained.

Please, any of you have go ahead with the following warning?

**WARNING**********************************************************************
ZONE EL1 WSW Zone (fG.z1)
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 S1 Sys (PVAVS)
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.

ZONE EL1 WSW Zone (fG.z1) has a THERMOSTAT-TYPE
of REVERSE-ACTION, which, when added to the issues listed
in the messages above, will cause excessive underheating.

Thank you!

SUMAC
Dante Garcia, LEED AP BD+C
Tel: +511.253.5355 Anexo 16 (Lima, Per?)
Cel: +51.989.685.769 (Lima, Per?)

_______________________________________________
Equest-users mailing list
http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org
To unsubscribe from this mailing list send a blank message to EQUEST-USERS-UNSUBSCRIBE at ONEBUILDING.ORG

Dante Garcia's picture
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Joined: 2013-05-22
Reputation: 0