"Insufficient heating warnings" in 3.64

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Dear all,

I have a LEED model, after switched the version into v3.64 from v3.63, a lot of insufficient heating warnings like below are reported, the percent of hours outside throttling range is also rise, while the model has been adjusted to no warnings and within 300hours in v3.63, it's a VAV system with electric cooling in summer and purchased heat in winter.

**WARNING**********************************************************************
ZONE E21 North Perim Zn (G.N1)
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.)

ZONE E21 North Perim Zn (G.N1) has a THERMOSTAT-TYPE
of REVERSE-ACTION, which, when added to the issues listed
in the messages above, will cause excessive underheating.

I noticed both No.33 and No.46 in file Bugfixes-047h.pdf mentioned there are enhancements for "insufficient heating capability" in V3.64, I tried increasing "heat sizing ratio" and "throttle range", but failed, can anyone give me some guidance to fix this issue ? I wish can benefit from soem new features in v3.64, but it's close to the end of project, there is little space to play.

Thanks in advance for your help!

Best Regards
Kevin Tang
Project Engineer | Energy Solution | Owens Corning China
Tel: 8621-6101 9622 | Fax 8621- 6101 9588
Kevin.tang at owenscorning.com

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dosking's picture
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Joined: 2011-01-16
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What is your reheat delta T?

Vikram Sami, LEED AP
Sustainable Design Analyst
1382 Peachtree St. NE, Atlanta, GA 30309
t: 404-443-7462 f: 404.892.5823 e: vikram.sami at perkinswill.com www.perkinswill.com
Perkins+Will. Ideas + buildings that honor the broader goals of society

Sami, Vikram's picture
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Joined: 2011-09-30
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It sounds like you need to specify a thermostat type of reverse action. I
would also increase the throttling range to 6. Look in the documentation for
a discussion regarding VAV, thermostats and throttling range or look in the
archives.

Carol

cmg750's picture
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Joined: 2010-10-05
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Thanks Vikram and Carol,

After increase reheat delta T(default is 30F,increase to 45 or 50) ,throttling range and even size ratio, it's back to normal, thanks for your help!

But I wonder why this happen after switch software version?

Kevin

________________________________
???: Carol Gardner [mailto:cmg750 at gmail.com]
????: 2010?9?2? 22:37
???: Sami, Vikram
??: (equest-users at lists.onebuilding.org); Tang, Kevin
??: Re: [Equest-users] "Insufficient heating warnings" in 3.64

It sounds like you need to specify a thermostat type of reverse action. I would also increase the throttling range to 6. Look in the documentation for a discussion regarding VAV, thermostats and throttling range or look in the archives.

Carol

dosking's picture
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Joined: 2011-01-16
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