Lack of hot water on electric.

[Lance]

Hi. I'm a newbie to caravans so please be kind to me.

We have an Elddis Avante 505 with a Truma water heater. We used the van extensively last year with no problems with the hot water. Yes, it would be nice to have more at a sitting but we got by. We nearly always used electric when on site but occasionally used gas.

The problem is that now, when running on electric, the volume of hot water is minimal. The first few seconds are nice and hot but after that it's all cold. Water flow is fine. On gas we have no problem.

Does anyone have an idea as to what I should be looking for? The system was fully drained down for winter and there are no leaks.

Thanks in advance,

Lance.

 

[Damian]

If you mean that when you set up on site, and plug in the electric, before filling the water system, then the heater will overheat and cut out, which accounts for a smal amount of hot water.

If that happens, then the heater will not reset until all power to the van has been disconnected for 15 minutes and the water tank filled with cold water.

When setting up on site, always leave connecting the mains electric until AFTER you have filled the water system properly.W

When leaving site, disconnect the mains supply BEFORE draining down the hot water tank for travelling.

 

[Lance]

Hi Damian.

Thank you for the reply.

I'm fairly sure its not that as we dont turn the heater on on until ready. And I'm very fastidious about draining down when not in use.

I probably didn't explain it very well.....

When on electric only, it will produce hot water, but only in small quantities. Have a 60 second shower and that thats all the not water gone. Wait a while and there is hot water again, all be it in small quantity.

If left overnight, there is no improvement in the volume of hot water.

I suspected there might be a busted pipe that was "wasteing" the water when the taps were on but couldn't see one.

The only thing I can think off is that when turning on the electric water heater, the pump (in the heater?) seems to run for a shorter period than I seem to recall from last year.

Hot water on gas is fine but maybe it's just my imagination however the volume "appears" to be slightly down on what I remember. It certainly isn't as small as when on electric.

Any further ideas?

Lon.

 

[Damian]

First of all, there is no pump inside the water heater.

It is simply a 10 ltr water container with an 850w electric heating element inside it, and a gas burner under it.

The flow of wate ris controlled by the van water pump and displacement of water, as hot is drawn off, cold replaces it.

Showering in a van is such a variable, some folk like hot water, others not so hot.

It depends how hot you like your shower water as to just how long it will last, considering most pumps push water out at about 7 ltrs a minute.

But, as hot is drwan, cold replaces it, cooling the water still in the tank.

To improve the recovery time, use gas and electric at the same time, but turn the gas of after showering.

Or , better still, use the site showers.

 

[Lance]

Hi Damian and thanks again for your reply.

What's confuseing me is the huge differance between the performance last year and this year.

Last year, when on site we only used electric and we used to have enough hot water for showers, washing up etc. When rallying we used gas and had as far as I can tell we had roughly the same volume of hot water as when on the electric.

This year, when on electric the volume of hot water is hugely reduced. However, when on gas the volume is as it was.

Are there seperate thermostats for gas and electric? If so, are they located in the same housing? My thinking here is that maybe a faulty thermostat could be the cause.

I'm pretty good at DIY so testing and replacing these would not be an issue.

Thanks once again,

Lance.

 

[ProfJohnL]

Hello Lance,

There are two thermostatic systems, and a faulty stat may be the cause, but without testing it is purely a guess.

With deference to your comment that you are pretty good at DIY so "testing and replacing these would not be an issue". I have to observe that a competent person would have already been able to test and diagnose the problem without recourse to the forum. So with the greatest respect, I advise you to have a person who is truly competent on Truma appliances diagnose and fix the problem.

Tampering with, (even just removing) Gas appliances is a mugs game, and I have seen and had to report on some very sad cases where DIY has gone wrong with near fatal consequences.

 

[gary]

You don't state the year of the van, earlier Truma elements were just 350w so take three times longer than gas to heat the water.

850W elements have a resistance of about 64 ohms, more than double than means it's a 350w element, these can though be swapped for the 850w

You do though say leaving overnight makes no difference so perhaps not the problem.

Busy sites drag the available voltage down and this affects heating times, is another possible?

You can use both gas and electric together to speed things up

 

[Lance]

Hi Damian.
I'm probably no explaining it clearly enough. Sorry.
When on electric, we have hot water but only in a very small volume. On gas we have a far more normal volume.
I was wondering if the two systems, gas and electric, have different thermostats? With a faulty electric one but a good gas one, that could replicate the symptoms. Is that possible?
I'm good at DIY and electrics so diagnostic testing shouldn't present a problem
Thank you again for your help so far
Lance.

 

[Lance]

Hello Prof.

Thank you for the info regarding thermostats. I will be checking the electrics one today as the symptoms point to a failure there.

Apreciate the concern when it comes to gas but theres no need to worry as if it's gas then it's going to a dealer to sort. From the symptoms I'm fairly sure it's electric and I'm very comfortable working with that (but shocked at the way SO many connections are simply insulated with tape!!).

Asked the forum as often a quick answer will saves hours of diagnostics.... especially with one of those faults where it's a case of "they all go wrong because of X. Just replace with Y and it will never fail again".

Hello Gary.
DOH! You're right. I forgot to say that its a 2005. Thank you for the resistance value and I'll be checking that later. If it's a 350 I'll be swapping that for a 850 ASAP.

Good thinking on the voltage drop when on a busy site but unfortunately the old girl is the same when at homne as well.

Thank you one and all. I'll report back on what I found.... knowledge may be useful to someone else later.

Lance.

 

[ProfJohnL]

Hello lance,

in some installation because of the way the caravan manufacture fits the appliance it is sometimes necessary to remove the heater from the caravan. removing it will require the disconnection of the gas pipe. if that is necessary, then job should be referred to a gas fitter.