RV Trip Planning Discussions

Go Back   iRV2 Forums > THE OWNER'S CORNER FORUMS > Newmar Owner's Forum
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 12-08-2018, 03:15 PM   #1
Member
 
Join Date: Oct 2016
Posts: 62
Another Roof Top AC/heat pump question.

Hi,
We left our 2005 Dutch Star plugged into 50 amp with the two heat pumps running in 45 degree weather. We were gone about three hours and when we returned, the front unit was humming but not making heat. The rear unit was working properly.

I shut off the front unit and then restarted it after about two minutes. It started up and was making heat again. It sounded normal. A while later, it started humming with no heat. I went to the roof and some of the cooling fins are iced over.

I have shut the unit down so the ice will melt. But, why would it ice over at this temperature? I am pretty sure there is a heating strip function but I thought it only operated at lower temperatures.

Does anyone have any idea what could be going on?
Thanks,
Pete
__________________

__________________
WVPete
2005 Dutch Star
2014 Nissan Frontier drive shaft disconnect
WVPete is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 12-08-2018, 04:44 PM   #2
1977-2006
 
USMCRET's Avatar


 
Newmar Owners Club
Join Date: Jul 2011
Posts: 1,626
Hey Pete, I can’t allow a fellow mountaineer’s question to go unanswered. Native Charlestonian here, long gone.

What you are experiencing is perfectly normal. When the unit is humming like that, it is deicing itself. If you let it continue to run, you’ll find that the unit will resume heating in a few minutes.

Ed
__________________

__________________
2005 Newmar KSDP 3910
ISC on a Spartan
USMCRET is offline   Reply With Quote
Old 12-08-2018, 04:50 PM   #3
Senior Member
 
wildtoad's Avatar
 
Join Date: Jul 2010
Posts: 3,546
Agree. I only have one but it goes into defrost mode for a while then resumes normal operation.
__________________
Tom Wilds
Blythewood SC
2016 Newmar Bay Star Sport 3004
2015 Jeep Wrangler 2DR 4WD Sahara, Automatic, Hard Top
wildtoad is offline   Reply With Quote
Old 12-08-2018, 05:26 PM   #4
"Formerly Diplomat Don"
 
Dutch Star Don's Avatar
 
Newmar Owners Club
Join Date: Apr 2005
Location: Moorpark, Ca.
Posts: 11,266
"WVPete"......when you use your unit as a heat pump, it just reverses the function of air conditioning. When you have it running as an AC unit, it's producing cool air inside and bowing the hot air outside. When you use it as a heat pump, there is a reversing valve that causes the unit to run just like an AC unit, but backwards. Now the hot air is blowing inside and the cold air is blowing outside. I imagine certain humidity levels make it ice faster. There is no heat strip in the unit.

Lastly, if you aren't aware, once the unit becomes ineffective, somewhere in the low 40's, it will cause your coach to switch over to your furnace.
__________________
Don & Mary
2019 Newmar Dutch Star 4018
2016 GMC Canyon 4WD Crew Cab
Dutch Star Don is offline   Reply With Quote
Old 12-08-2018, 05:55 PM   #5
Senior Member
 
bruceisla's Avatar
 
Join Date: Oct 2012
Location: Bushnell, FL
Posts: 6,256
As Don said ... it's probably normal. However, icing can be caused by other factors. Make sure your airflow is sufficient (clean the filters). Here's the documentaion from Dometic:


"Defrost Cycle (Heat Pump Models Only)
To avoid frost formation
on the outside
coil and to obtain
maximum
performance
when the outside
temperature
is less than 42 F (6 C) and greater
than 30 F
(-1 C), a defrost
cycle will be initiated.
While operating
in this temperature
range the
compressor
continuous
run time is limited
to 25 minutes.
When this time is accumu
-
lated, the fan will shut OFF, the refrigerant
flow will be reversed,
and the compres
-
sor will continue
to run for 4.5 minutes.
During
this 4.5 minute
period,
the LCD will
toggle
between
HP and Defrost.
The refrigerant
flow will then be reversed
and after
a 30 second
delay the fan will resume
operation.
This cycle will remove
any frost
formation
on the outside
coil. This cycle will repeat
itself until the outside
tempera
-
ture is greater
than 42 F (6 C). If the outside
temperature
becomes
less than 30 F
(-1 C) the heat pump will shut OFF and the auxiliary
heat (if provided)
will turn on"
__________________
2005 Newmar Essex 4502, 2013 Caddy SRX
1997 HR Endeavor 37, CAT, 1996 Geo Tracker
bruceisla is offline   Reply With Quote
Old 12-09-2018, 06:09 AM   #6
Member
 
Join Date: Oct 2016
Posts: 62
Another Rooftop A/C heat pump question

Thanks for all these replies. I have had this DS for a little over two years and I am still learning things. I think the icing may have happened because my wife was not feeling well and kept turning up the thermostat so the unit had to run longer. When I brought the set temp back to 65, it doesn't ice up, at least not when it is 45 degrees out.
Thanks again for all the help. I'm really happy to hear it is functioning properly. I had cleaned the fins this past summer and the filters too but I think the filters can stand to be cleaned again.
Pete
__________________
WVPete
2005 Dutch Star
2014 Nissan Frontier drive shaft disconnect
WVPete is offline   Reply With Quote
Old 12-09-2018, 08:19 AM   #7
Senior Member
 
harleyjt's Avatar
 
Newmar Owners Club
Workhorse Chassis Owner
Join Date: Jan 2015
Location: Olive Branch, MS
Posts: 2,358
Quote:
Originally Posted by bruceisla View Post
As Don said ... it's probably normal. However, icing can be caused by other factors. Make sure your airflow is sufficient (clean the filters). Here's the documentaion from Dometic:


"Defrost Cycle (Heat Pump Models Only)
To avoid frost formation
on the outside
coil and to obtain
maximum
performance
when the outside
temperature
is less than 42 F (6 C) and greater
than 30 F
(-1 C), a defrost
cycle will be initiated.
While operating
in this temperature
range the
compressor
continuous
run time is limited
to 25 minutes.
When this time is accumu
-
lated, the fan will shut OFF, the refrigerant
flow will be reversed,
and the compres
-
sor will continue
to run for 4.5 minutes.
During
this 4.5 minute
period,
the LCD will
toggle
between
HP and Defrost.
The refrigerant
flow will then be reversed
and after
a 30 second
delay the fan will resume
operation.
This cycle will remove
any frost
formation
on the outside
coil. This cycle will repeat
itself until the outside
tempera
-
ture is greater
than 42 F (6 C). If the outside
temperature
becomes
less than 30 F
(-1 C) the heat pump will shut OFF and the auxiliary
heat (if provided)
will turn on"

Good to know. Thanks for posting.
jt
__________________
2005 Newmar Kountry Star Gas 3742
Workhorse W24, 8.1L/Allison 5-spd
JT, Em & the boys, Kong & Baxter (rescued grey tabbies)
harleyjt is offline   Reply With Quote
Old 12-09-2018, 12:19 PM   #8
Senior Member
 
bruceisla's Avatar
 
Join Date: Oct 2012
Location: Bushnell, FL
Posts: 6,256
Quote:
Originally Posted by WVPete View Post
I had cleaned the fins this past summer and the filters too but I think the filters can stand to be cleaned again.
Pete



FWIW, I clean filters once per month ... sometimes more frequently.
__________________
2005 Newmar Essex 4502, 2013 Caddy SRX
1997 HR Endeavor 37, CAT, 1996 Geo Tracker
bruceisla is offline   Reply With Quote
Old 12-10-2018, 05:08 AM   #9
Member
 
Join Date: Oct 2016
Posts: 62
Quote:
Originally Posted by bruceisla View Post
FWIW, I clean filters once per month ... sometimes more frequently.
I cleaned the filters again today. I was surprised at the amount of dirt that was left in the water.

Also, I discovered that the one of the vents that put out heat was aiming air at the main thermostat control. So when the back unit comes on, warm air is blowing on the front thermostat preventing it from running. This is sort of un-related to my original post, but changing the aim has made the front unit cycle more regularly and keep the front warmer at a lower setting.

Like I said earlier, I am still learning stuff about RVing!!
__________________
WVPete
2005 Dutch Star
2014 Nissan Frontier drive shaft disconnect
WVPete is offline   Reply With Quote
Old 12-10-2018, 05:56 AM   #10
Senior Member
 
bruceisla's Avatar
 
Join Date: Oct 2012
Location: Bushnell, FL
Posts: 6,256
Quote:
Originally Posted by WVPete View Post
I cleaned the filters again today. I was surprised at the amount of dirt that was left in the water.

Also, I discovered that the one of the vents that put out heat was aiming air at the main thermostat control. So when the back unit comes on, warm air is blowing on the front thermostat preventing it from running. This is sort of un-related to my original post, but changing the aim has made the front unit cycle more regularly and keep the front warmer at a lower setting.

Like I said earlier, I am still learning stuff about RVing!!

__________________

__________________
2005 Newmar Essex 4502, 2013 Caddy SRX
1997 HR Endeavor 37, CAT, 1996 Geo Tracker
bruceisla is offline   Reply With Quote
Reply

Tags
heat, heat pump, roof



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
one Roof top a/c and one heat pump? Md11fpilot Monaco Owner's Forum 9 04-16-2018 04:07 PM
Top off or not top off that is "def" question kohraptor Sprinter Chassis Forum 27 11-16-2016 09:40 AM
Roof top a/c heat pump problem vraines RV Systems & Appliances 3 05-28-2013 12:18 PM
roof top ac-heat pumps Bugzme Monaco Owner's Forum 6 11-05-2010 05:59 PM
To heat pump or not heat pump Bruce and Jenna Excel Owner's Forum 17 04-15-2009 11:20 PM

» Featured Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 03:45 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.