Hi All,
I have read with interest most of the posts on the Coleman Hot water on Demand unit as I was given one by my Dad that was brand new, hadn't been used, was over 3 years old and had been through a flood. Suffice to say it didn't work when we tried it with the stand alone gas cannister.
Here is what i have done to finally get it going consistently, without the help of Coleman or any service agents.
First off the
battery was dead. I had read that it was possible to hook up an external 6v supply to the
battery terminals to bypass the
battery and get it to turn on but my 6v supply did not have enough current supply and i could not get it to turn on. Also the 6v outlet for the water pump was so badly corroded that it fell apart so i had to get a new socket and solder it onto the unit. I tested the pump on its own with a 6v supply and the pump worked , so at least that was 1 thing that worked. So off i went to Jaycar for a new 6v SLA
battery and a 2.5mm Socket for the pump outlet.
Taking the unit apart was fairly easy. I soldered the new outlet in for the pump and hooked up the
battery. I thought i would give it a go straight away without the gas cannister to see if i was wasting my time and
well as soon as i turned the on knob the water pump came to life and i could hear the firing mechanisim for the gas burners coming on. So far so good. I plugged in the 240v charger and let it charge the
battery. The yellow LED light will come on if the
battery is low on power when in use and when you plug in the charger the charge LED will be RED. Once the
battery is fully charged that LED will go to GREEN. Also as mentioned in some of the other posts, this unit will NOT work when the charger is plugged in. Not with the 240v charger or the 12v charger.
I must say though that before i bought the new
battery i called into a Coleman agent (No names) and enquired as to how much it might cost to get the unit back to Coleman for them to take a look at it. As it was over 3 years old, I did not have a receipt, the Agent said it could cost at minimum $150. I nearly fell over. I then told him what i had found and that i had opened the case and it had been through a flood,
well that's when it really got interesting. He said Coleman would not take the unit anyway as they could not warrant anything that had been water damaged and the fact i had opened the case was another no no that Coleman would not accept. I enquired about spare parts and again i was told there are no spare parts except for a new water pump,
battery and shower head attachment. Great i said. I was on my own so i set off back to work on this thing. It had potential, i just needed to know how it worked.
So now with a fully charged
battery i connected the gas cannister and gave it a whirl. I'm not sure if it fired first go but i was able to get it to light and fire up and i had hot water. My problem was that i could not get it to light consistently. The unit has more safety features than a jumbo jet so let me explain them to you.
Inside the unit there is a tilt switch. This is connected to a thermostat which is then connected to the Electronic gas solenoid that allows gas to go through to the burners.
This means that if you knock the unit over or bump it while it is on, it will shut off the gas solenoid and the burners will go out. Also, if the water reaches it's set
temperature (about 70 degrees C ) then it shuts down the solenoid and the burners go out. You can bypass these units if you wish but probably not recommended. I bypassed them during my fault finding mission to rule out certain events.
I had most of my components working. There are 2 circuit boards in the unit, 1 is the charge circuit and the other is the control board. Both of these board had been through the flood but they were both
well encapsulated with some form of silicon that had kept out the water. Both boards seems to be ok but just to make sure i went over every circuit board solder joint with a soldering iron just to make sure there was no dodgy joints. I knew the charge circuit was working and tested it with a multimeter, and it seemed as thought the control board was working as i was able to get it to fire up and stay on. There is also a water flow sensor that will also stop the burners if there is no water go through the unit.
So, back to my problem. I could get it fire up but not every time. Once it fired I could turn it off and on as many times as I liked, in succession. My problem was when i left it for 15-20mins in the off state , for example to charge it , and then come back to turn it on. I was having a gas flow problem, i could not get the gas solenoid to fire to let the gas through to the burners.
If i took the solenoid ouot of the gas line, and then tested the unit, the solenoid would fire. I put it back together and tested it and again all was good. Burners fired up and hot water. When i left it again for 20mins, again the solenoid would not fire.
To fix my problem i have determined that I have to clear the gas lines of Gas after i have finished using it. I disconnect the gas cannister and turn the unit on straight after the last use. The clears the lines, fires the solenoid and rids the lines of any built up gas pressure. It seems the pressure in the line on the input side of the solenoid and On knob was causing the solenoid to stick, thus not allowing gas to flow through to the burners. If i clear the lines after every use, then i have no problems.
I just thought i would share with you all what i have done to get this unit to run. I am a licenced Electrician but any handy person should be able to get one of these going as long as the fault is not on the circuit board. There was no clear information on the internet that i could find that told me exactly how these things operated. The manual is pretty useless, every fault says return to Coleman. I have now bought a Gas hose to allow connection to a bigger gas bottle and I will now also purchase the shower head. There is a recirculation diagram out there that is also very useful.
Thanks for reading and happy camping.
cheers