Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 27-08-2014, 12:03   #1
Registered User
 
Tia Bu's Avatar

Join Date: Jul 2009
Location: South Carolina
Boat: 40' Jeanneau
Posts: 454
16k BTU AC and Water Heater on 30 amp Service

Do any of you currently have both a 16,000 btu air conditioner and a water heater running on the same 30 amp service?

I've got an older 16,000 btu Marine Aire unit. Thinking of adding a water heater, but think the locked rotor startup loads on the compressor would probably blow the main breaker when the water heater is also on. Is there a way to test this out without buying and installing the water heater first?

Would a hard-start capacitor or SmartStart kit help? Is there an incremental way to go about testing these solutions?

Any advice appreciated.
__________________

__________________
Tia Bu is offline   Reply With Quote
Old 27-08-2014, 12:07   #2
Registered User
 
ranger42c's Avatar

Join Date: Aug 2012
Location: Maryland, USA
Boat: 42' Sportfish
Posts: 2,985
Re: 16k btu AC and water heater on 30 amp service

We have one 16K BTU unit and raw water pump, plus water heater, plus two-burner electric stovetop, plus one small fridge on one 110V leg of our 50-amp service, with no overload problems, if that helps.

-Chris
__________________

__________________
Selby Bay, South River, Chesapeake Bay, USA.
ranger42c is offline   Reply With Quote
Old 27-08-2014, 12:10   #3
Registered User
 
Tia Bu's Avatar

Join Date: Jul 2009
Location: South Carolina
Boat: 40' Jeanneau
Posts: 454
Re: 16k btu AC and water heater on 30 amp service

Well, thanks, that kind of helps, but if you're just using one leg of the 50 amp service, does that mean you have 50 amp, 110 volt service?
__________________
Tia Bu is offline   Reply With Quote
Old 27-08-2014, 12:16   #4
Registered User
 
ranger42c's Avatar

Join Date: Aug 2012
Location: Maryland, USA
Boat: 42' Sportfish
Posts: 2,985
Re: 16k btu AC and water heater on 30 amp service

I have roughly the same amount of stuff running on the other leg, too.

Just thought that first leg's worth, so to speak, would be roughly equivalent to one of your 30-amp supplies.

-Chris
__________________
Selby Bay, South River, Chesapeake Bay, USA.
ranger42c is offline   Reply With Quote
Old 27-08-2014, 12:36   #5
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,062
Re: 16k btu AC and water heater on 30 amp service

My boat has only a single 30 amp service, I run a 16K ac and a 5K ac as well as battery charger, water heater TV's, multiple cell chargers, toaster, whatever. I can easily run the 16K AC and everything except the 5K AC, if I have the water heater on, 11 amp draw, I have the small AC off 5 amp draw.
With everything running including the water heater and 16K AC, but not the 5k ac I have a 26 amp draw, so far no problems.

On edit, the water heater only needs to be on for an hour or so a day it seems to keep water hot pretty well.

My 16K Ac is ancient and it's start up load is pretty big, but on shore power no problems

I keep thinking of things, sorry. If you install a 220V heater element in a water heater running off of 110V you will decrease it's current draw and of course it's heat output greatly, if I had a 220V heating element I could run everything including both AC's, just barely, but as the heater needs to be on only for so short a period I haven't bothered
__________________
a64pilot is offline   Reply With Quote
Old 27-08-2014, 12:53   #6
Registered User
 
Tia Bu's Avatar

Join Date: Jul 2009
Location: South Carolina
Boat: 40' Jeanneau
Posts: 454
Re: 16k btu AC and water heater on 30 amp service

Tell me more about installing a 220 volt heating element. I'm not sure I follow.
__________________
Tia Bu is offline   Reply With Quote
Old 27-08-2014, 13:02   #7
Registered User
 
travellerw's Avatar

Join Date: Jan 2014
Location: Martinique
Boat: Fortuna Island Spirit 40
Posts: 1,726
Re: 16k btu AC and water heater on 30 amp service

Not sure if it is available for marine AC units, but in RV ACs you can install a "soft start" kit to help with startup load. Its basically a big capacitor that supplies some of the current for the start up.

I know there are universal kits that might work for a marine AC.
__________________
travellerw is offline   Reply With Quote
Old 27-08-2014, 14:11   #8
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,062
Re: 16k btu AC and water heater on 30 amp service

A 220 resistance heating unit run off of 110V will I think pull about half the power of a 110V one, it will produce only about half as much heat of course meaning it will take twice as long to get the water to the same temp, but it would keep me just under 30 amps. if I ran both AC's and the water heater.
My old Marine Air 16K AC does have a large start up current, but on shore power it's no problem, I don't believe you need a soft start kit on shore power even with the hot water heater on.
__________________
a64pilot is offline   Reply With Quote
Old 27-08-2014, 17:41   #9
Registered User
 
Tia Bu's Avatar

Join Date: Jul 2009
Location: South Carolina
Boat: 40' Jeanneau
Posts: 454
Re: 16k btu AC and water heater on 30 amp service

Thanks, guys, for the input. I think I see the way through, now.
__________________

__________________
Tia Bu is offline   Reply With Quote
Reply

Tags
service, water

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

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
For Sale: Mermaid 16500 BTU ac/ heater vtsailguy Classifieds Archive 10 02-07-2013 16:09
For Sale: Marine Air 16K BTU Reverse cycle A/c familycruisers Classifieds Archive 8 30-01-2013 07:15
Gas Water Heater or Combined Calorifier / Immersion Heater ? simonmd Plumbing Systems and Fixtures 5 30-12-2010 08:50



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 01:52.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.