I found this response to this question on one of the RV.net sites.
GregM


"Nick Badame Refrig.
Cape May Court House, N.J.
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Joined: 08/23/2006
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Posted: 01/27/08 08:31am Link | Quote | Print | Notify Moderator

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Hi John,

Your basement HP does not have an electric resistance back-up like regular Home type heat pumps. So, below 35 deg. it will freeze up and have no means to defrost. That is why the controls cut it out around 40 deg. and usually will have a redundant system take over. I run 2 basement heat pumps with a 45,000btu diesel fired ProHeat as secondary.

Good Luck
Nick-


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MCI 102C3 40' 2006' Bus Conversion by Atlantic Custom Coach
Detroit 475hp 8V92t w/Allison Ht750 auto
Master Mason, Cannon Lodge #104 S. Seaville N.J.
FMCA# F-27317-S
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