check out the new remote control Jockey Wheel SmartBar Canegrowers rearview170 Cobb Grill Skid Row Recovery Gear
Members Login
Username 
 
Password 
    Remember Me  
Post Info TOPIC: Pre heating hot water for instantaneous gas hot water system


Veteran Member

Status: Offline
Posts: 26
Date:
Pre heating hot water for instantaneous gas hot water system


Hi

 

We are on the road at present doing what I refer to as our  Spangled Drongo run, as it is the only bird that flys south in the winter. We are finding that in places our Camec instantaneous hot water system cant quite deliver a hot shower. As they are designed to heat up to 37 degrees above the temp of the incoming water, where it is exceptionally cold and the incoming water is in single figures we can at times only get 40degrees out of the unit. I was wondering if anyone has had this problem and solved it using a portable instantaneous gas hot water heater to preheat the incoming water. I was thinking of something like setting up a unit with a bayonet connection and running the cold water into it and then into the van water inlet at the lowest temp setting. Of course this wouldn't work when running off the tank and pump unless I altered the plumbing coming into the Camec, which is possible. Has anyone tried this? Any ideas?

Cheers.

Peter 



__________________


Guru

Status: Offline
Posts: 8493
Date:

G'day Peter, Welcome to GN's.

I have heard others complain about the delivery of hot water from instantaneous heaters, unfortunately I know of none that have had a solution other that to change water heater to Gas/electric unit or diesel heated units.

__________________

Possum; AKA:- Ali El-Aziz Mohamed Gundawiathan

Sent from my imperial66 typewriter using carrier pigeon, message sticks and smoke signals.



Senior Member

Status: Offline
Posts: 159
Date:

How hot do you want your shower water?
I have a domestic Rinnai Instaneous HWS in my van and set my shower water temp to 39 which I find comfortable any temp above 40 is starting to get too hot for me.

Ken



-- Edited by kgarnett on Wednesday 7th of July 2021 02:30:08 PM

__________________


Guru

Status: Offline
Posts: 7314
Date:

Do the opposite of what we did in southern France. We put the bottles of water out at night to cool down so we had cool thermal mass during the 43°C days. It worked well, nice cool wine.

So keep a container of water indoors overnight so it's warmer in the morning.

IMG_3035.jpg



Attachments
__________________

Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



Guru

Status: Offline
Posts: 7640
Date:

Run it on cold . Then when slightly heated come through? Itll feel hot ! Third world issues ! Lol

__________________
Whats out there


Senior Member

Status: Offline
Posts: 159
Date:

Feed a small amount of the hot water output back into inlet side of the pump.
Ken



-- Edited by kgarnett on Wednesday 7th of July 2021 01:03:21 PM

__________________


Veteran Member

Status: Offline
Posts: 26
Date:

Thanks Ken. That is worth investigating. I will have a look at the plumbing when i next get the time and see what is involved.

__________________


Guru

Status: Offline
Posts: 7640
Date:

Depends on line pressures ?

__________________
Whats out there


Veteran Member

Status: Offline
Posts: 26
Date:

Yes, cutting back pressure increases temp but we have been places where the water is so cold we cant get the pump to run properly on such a slow level. Been looking into this a bit more and it comes down to the camec being undersized. It only develops some 35000btu whereas a more expensive Truma unit can produce up to 60000. You get what you pay for $1k as opposed to $2.5.

__________________


Guru

Status: Offline
Posts: 7314
Date:

At home we have two 3 phase electric 20kW instantaneous hot water systems. They heat water up by X amount. In summer we switch them to only run off 2 phases at they get too hot.

Your options are to start with warmer water or to slow the rate the water goes through the unit.



__________________

Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



Senior Member

Status: Offline
Posts: 491
Date:

Hi all; Had a problem with the hot water heater after i changed the sacrificial anode and hardly any hot water out of any of the taps. The problem may be the tempting valve ( this valve mixes hot and cold water together, so as the hot water only is not to hot to scald you. The problem was the small screen in the tempting valve was partly blocked and needed removing from our caravan, cleaning ( was easy outer the caravan than in ) and reinstalling. No problems since.

__________________


Guru

Status: Offline
Posts: 4711
Date:

Stephen, is not yours a storage water heater? The OP has an instant one.

__________________

PeterD
Nissan Navara D23 diesel auto, Spaceland pop-top
Retired radio and electronics technician.
NSW Central Coast.

 



Senior Member

Status: Offline
Posts: 207
Date:

Coming in a bit late here because Ive only recently signed up . . . .

I had the same problem so I bought a 2000 watt instantaneous electric hot water heater which I plumbed into the inlet line servicing the gas hot water heater. The electric heater has a regular cord and plug so no wiring in required. Tested on its own, the electric unit made the water tepid but, with lukewarm water rather than icy cold water feeding into the gas unit, I have strong, hot water in the shower. And, in warmer weather, I simply unplug the electric unit.

__________________


Veteran Member

Status: Offline
Posts: 26
Date:

Thanks mein. That is exactly what i needed to read. Think i will do the same but with a portable gas heater. Im also going to insulate the hot water pipes. Cheers. Peter.

__________________


Guru

Status: Offline
Posts: 7640
Date:

I have seen copper pipe bent around exhaust to heat a seperate tank . Relying on thermal to circulate. Heat tank .

__________________
Whats out there


Veteran Member

Status: Offline
Posts: 26
Date:

Good idea. Will have a look at whats involved with doing that. cheers.

 



__________________


Guru

Status: Offline
Posts: 1471
Date:

I wonder, the hose from the pump to your instantaneous hws, if that had a short 400mm section of copper pipe that sat on top of the heated air of the hws it would preheat the water.

Have a "T" piece so in warm weather it is disabled.
Tony.

__________________

Be nice... if I wanted my school teacher here I would have invited him... 



Veteran Member

Status: Offline
Posts: 26
Date:

Thanks for the suggestion. Combination of lock down and bad weather and the caravan being more than 5k from where I am means I wont be doing anything for a while but that is another good idea I will check out. thanks. 

 



__________________
Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.

Tweet this page Post to Digg Post to Del.icio.us
Purchase Grey Nomad bumper stickers Read our daily column, the Nomad News The Grey Nomad's Guidebook