Pre heating hot water for instantaneous gas hot water system
Petemox said
09:37 PM Jul 6, 2021
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
Possum3 said
11:31 PM Jul 6, 2021
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.
kgarnett said
11:50 AM Jul 7, 2021
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
Whenarewethere said
12:51 PM Jul 7, 2021
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.
Run it on cold . Then when slightly heated come through? Itll feel hot ! Third world issues ! Lol
kgarnett said
01:01 PM Jul 7, 2021
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
Petemox said
02:05 PM Jul 7, 2021
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.
Aus-Kiwi said
08:08 PM Jul 7, 2021
Depends on line pressures ?
Petemox said
08:41 PM Jul 7, 2021
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.
Whenarewethere said
08:09 AM Jul 8, 2021
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.
valiant81 said
09:53 AM Jul 8, 2021
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.
PeterD said
10:14 AM Jul 8, 2021
Stephen, is not yours a storage water heater? The OP has an instant one.
Mein said
08:35 PM Jul 13, 2021
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.
Petemox said
10:20 PM Jul 13, 2021
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.
Aus-Kiwi said
08:21 AM Jul 15, 2021
I have seen copper pipe bent around exhaust to heat a seperate tank . Relying on thermal to circulate. Heat tank .
Petemox said
11:50 AM Jul 15, 2021
Good idea. Will have a look at whats involved with doing that. cheers.
Eaglemax said
10:39 AM Jul 17, 2021
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.
Petemox said
11:46 AM Jul 17, 2021
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.
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
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.
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
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.
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
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.
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.
Good idea. Will have a look at whats involved with doing that. cheers.
Have a "T" piece so in warm weather it is disabled.
Tony.
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.