When i first bleed the air out of the hot water tap and switch on the power i get a hot water. After using the hot water for showering etc it starts to run cold suggesting the the thermostat is not working to allow power to return to reheat the water. If i then turn the power off and leave for 5 mins and then turn on again the water will heat up.This happens repeatably. Any suggestions to remedy this problem.
Truma Ultrastore Water Heater
- Thread starter Baz
- Start date
Parksy
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- Nov 12, 2009
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The water is cold as it enters the caravan from the Aquaroll where it is stored and heated in a boiler.
As you use the hot water for showering etc; it is replaced in the boiler with cold water from the Aquaroll.
After five minutes the water in the boiler will have been heated by the boiler element so you will have hot water again.
A caravan boiler has nowhere near the same capacity as your domestic boiler at home
As you use the hot water for showering etc; it is replaced in the boiler with cold water from the Aquaroll.
After five minutes the water in the boiler will have been heated by the boiler element so you will have hot water again.
A caravan boiler has nowhere near the same capacity as your domestic boiler at home
- Mar 14, 2005
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The Ultrastore water heater is not an instantaneous water heater, it is Parksy says a storage water heater. The water stored in the heater will take between 20 and 30 main to heat from cold to a full tank of hot. As there is only a limited quantity of hot water, when you shower you will normally mix it with cold water at the tap to get the right temperature, and by doing so the hot water will go a little further and you might get two frugal showers out of it.
As you use the hot, the heaters tank starts to fill from the bottom with cold, so you can get most of the hot out and use it.
I suggest you refer to the instructions for more information.
As you use the hot, the heaters tank starts to fill from the bottom with cold, so you can get most of the hot out and use it.
I suggest you refer to the instructions for more information.
I understand where you are coming from but the problem is that it does not reheat. It will only reheat if i turn off wait for 5 mins and switch on again.
Damian
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- Mar 14, 2005
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How old is the heater?
From your description it sounds as if the overheat cutout is operating, which may be symptomatic of a failing thermostat.
As the thermostat is incorporated with the element as a complete unit it would need to be replaced.
From your description it sounds as if the overheat cutout is operating, which may be symptomatic of a failing thermostat.
As the thermostat is incorporated with the element as a complete unit it would need to be replaced.
Last edited:
I believe you maybe right as i understand that to be the case. The unit is coming up to 10 years old so like me is getting worn out. Thanks for your reply.
Not replaced element yet as caravan been laid up for the winter. However i am going to carry out a descale first and go on from the results of that.
- Jun 20, 2005
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Hi Baz - from NZ - I know this post was a few years ago but I am having same issues with my Truma Waterheater - heats up great from filling it, then I use some water and it goes cold but can only get it hot again by turning the unit on and off.
Element and Thermostat are fine - all tested great. Did you get yours sorted in the end or did you simply replace the element?
The older heater elements were 450W and later ones 800W also we can get 1200W heater elements (non Truma) The 450W versions weren't the fastest to reheat. How long do you leave it? or have you tried waiting with it on? The simple thermostat is bolted quite close to the heater element and probably has quite a large hysteresis, so will have to cool down quite a lot before switching back on on its own , Removing the power doesn't reset it , a reduction in temperature as its just a simple bimetallic switch. if it is failing ( hysteresis getting bigger) then replacement of the heater element ( the 800W and 1300W come with the thermostat wired in. The 450W had a separate thermostatic switch. You need to open up the outer cardboard cover where the mains wires go into the unit to see which version you have.I have never seen a 450W version , but I believe the 450W heater unit is not physically compatible with the 800W replacement heater assemblies.
Thx Ian
Its an 800w version. BN-103 Model. I have left it on for a long period hoping it would reheat but the only way to get it back to hot is to turn the main switch off, wait for 5 mins, turn back on again and wait for it to reheat - same issue Baz had. My feel is that it should keep the same heat continuously as we only use it for dishes (no shower or bathroom in the van) ie, there is no way we are using 10L every time we do dishes.
I have tested the existing Element and Thermostat and get good ohm readings - plus the heater does heat up initially so it cannot be an element issue.
Possibly air getting in somewhere but then I have re-inserted all the John Lewis fittings, even replaced a few, and re-tightened all the plastic screw/bolt fittings.
Its an 800w version. BN-103 Model. I have left it on for a long period hoping it would reheat but the only way to get it back to hot is to turn the main switch off, wait for 5 mins, turn back on again and wait for it to reheat - same issue Baz had. My feel is that it should keep the same heat continuously as we only use it for dishes (no shower or bathroom in the van) ie, there is no way we are using 10L every time we do dishes.
I have tested the existing Element and Thermostat and get good ohm readings - plus the heater does heat up initially so it cannot be an element issue.
Possibly air getting in somewhere but then I have re-inserted all the John Lewis fittings, even replaced a few, and re-tightened all the plastic screw/bolt fittings.
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