In coming water temperatures

[IanB1485]

@charlesdobson I take your point about the higher pressure pumps , but with the flow at the tap reduced, the pressure in the boiler will be higher and reduce the kettling effect . A shower takes less water per second so the pressure in the boiler remains high .Your posts are slightly confusing/contradictory - just to clarify
. the water temperature is poor at the taps , but OK at the shower in the colder weather OR the shower also struggles ?.
If the former then it definitely flow rate that is limiting the temperature, if the latter then there may be a fault with the boiler controls .
What model of Imass do you have as on one it mentions water from an 'onboard tank' which would provide a supply of 'prewarmed' water which could be an option to fit inside your caravan

 

[charlesdobson]

@charlesdobson I take your point about the higher pressure pumps , but with the flow at the tap reduced, the pressure in the boiler will be higher and reduce the kettling effect . A shower takes less water per second so the pressure in the boiler remains high .Your posts are slightly confusing/contradictory - just to clarify
. the water temperature is poor at the taps , but OK at the shower in the colder weather OR the shower also struggles ?.
If the former then it definitely flow rate that is limiting the temperature, if the latter then there may be a fault with the boiler controls .
What model of Imass do you have as on one it mentions water from an 'onboard tank' which would provide a supply of 'prewarmed' water which could be an option to fit inside your caravan

The quicker you run water over the boiler the less time it has to heat it , I have tried various pumps with the boiler and found the lower litres per minute works better with it , remembering that most caravans run on a fairly small bore pipework to start with which can be a restriction in itself, so the higher psi pump isn’t a benefit, it just constantly cuts in and out

 

[toad a caravan]

How small a bore?

 

[ProfJohnL]

I suspect you are expecting domestic hot water performance in a caravan, and sadly you simply do not have the same equipment to be able to deliver that type of performance.

You have indirectly indicated you have an Imass system, but you have not told us which make and model of caravan you have.

As Roger has pointed out the Imass information on line states the heater can only raise 3.3 litres of water per minute by 37.7C. You must be using more water than 3.3l/m if your unable to get 40C water.

 

[charlesdobson]

I suspect you are expecting domestic hot water performance in a caravan, and sadly you simply do not have the same equipment to be able to deliver that type of performance.

You have indirectly indicated you have an Imass system, but you have not told us which make and model of caravan you have.

As Roger has pointed out the Imass information on line states the heater can only raise 3.3 litres of water per minute by 37.7C. You must be using more water than 3.3l/m if your unable to get 40C water.

Well hopefully I’m going to cure this problem, the heater had no problem during the summer going to 45/50C , I’m going to replumb the caravan so that water for the heater flows through the onboard tank with a heat mat underneath to pre warm the water , hopefully this cures the problem!

 

[toad a caravan]

Are heat mats available between 4 and 6kw and does the heat go directly into the water without dispersing else where?

 

[charlesdobson]

Are heat mats available between 4 and 6kw and does the heat go directly into the water without dispersing else where?

It’s a heat mat which you attach to the bottom of the tank , was a ****** of job getting the on board tank in the caravan out and rerouting the cold water away from it , but hopefully once all the bits arrive it should be source of warm water for the heater if it works 🤞

 

[charlesdobson]

It’s a heat mat which you attach to the bottom of the tank , was a ****** of job getting the on board tank in the caravan out and rerouting the cold water away from it , but hopefully once all the bits arrive it should be source of warm water for the heater if it works 🤞

Are heat mats available between 4 and 6kw and does the heat go directly into the water without dispersing else where?

Sorry the heat mat I ordered is a 6kw unit , but all depends where your using it I suppose, technically I think you buy an immersion style heater like you have at home , not sure if a plastic tank could withstand that, and would the water be too warm then??

 

[Sam Vimes]

If at any point you are storing hot water, as opposed to just using instantaneous heating, then you need to ensure that, that hot water is periodically taken to a temperature above 60degC to avoid bacterial growth such as Legionella.

 

[charlesdobson]

If at any point you are storing hot water, as opposed to just using instantaneous heating, then you need to ensure that, that hot water is periodically taken to a temperature above 60degC to avoid bacterial growth such as Legionella.

That is a very good point, maybe will have to rethink my plans

 

[IanB1485]

As Sam Vines says stored water should be sanitised to avoid legionella and other single cell organisms , but only if it goes above 23 deg C . Commercial buildings often have large water tanks on the top floor/roof used for both fresh drinking water and the fire suppression sprinkler systems ( a recent one in Salford keys has a 10,000 gallon tank). The water temperature is monitored by the BEMS . The temperature isn't raised to kill bacteria , but an alarm goes off on the BEMS control system if it goes above 20 Deg C.
6kW seems a bit excessive , have you thought of fish tank heaters, simply dropped into the tank - they come in different wattages and have an inbuilt thermostats ( https://www.finest-filters.co.uk/hepo-hp-608-submersible-quartz-aquarium-heaters) not dear either. Also we used to use trace heaters on exposed water pipes and drains on freezer rooms , You wrap it around the water pipe and insulate. https://www.frostprotection.co.uk/6m-pre-made-12W. There is a version which can be inserted in large bore drain pipes (sealed in silicone rubber)or strapped to the outside and are self regulating.

 

[charlesdobson]

As Sam Vines says stored water should be sanitised to avoid legionella and other single cell organisms , but only if it goes above 23 deg C . Commercial buildings often have large water tanks on the top floor/roof used for both fresh drinking water and the fire suppression sprinkler systems ( a recent one in Salford keys has a 10,000 gallon tank). The water temperature is monitored by the BEMS . The temperature isn't raised to kill bacteria , but an alarm goes off on the BEMS control system if it goes above 20 Deg C.
6kW seems a bit excessive , have you thought of fish tank heaters, simply dropped into the tank - they come in different wattages and have an inbuilt thermostats ( https://www.finest-filters.co.uk/hepo-hp-608-submersible-quartz-aquarium-heaters) not dear either. Also we used to use trace heaters on exposed water pipes and drains on freezer rooms , You wrap it around the water pipe and insulate. https://www.frostprotection.co.uk/6m-pre-made-12W. There is a version which can be inserted in large bore drain pipes (sealed in silicone rubber)or strapped to the outside and are self regulating.

I like yourself worked in the construction and maintenance trade for many years , know all about bms systems unfortunately, spent years taking temperatures and running water in rest rooms of many education and government buildings and adjusting solenoids , as for my problem, I’ve give up warming water for the gas heater, I’ve bought a secondhand propex electric water heater to put in place of the inboard tank and will run the two water systems using a couple of solenoids so I can use either at any given time, well that’s the plan , once I get it all plumbed up and get the wiring sorted

 

[Sam Vimes]

The bacteria will lay dormant below 20deC but multiple between that and about 45.

 

[charlesdobson]

The bacteria will lay dormant below 20deC but multiple between that and about 45.

I hoping that using a mixture of the instantaneous gas heater on better days and propex electric heater on the colder days and bit of clever plumbing should work, anyone with any clever ideas how to integrate them both please tell me

 

[RogerL]

I hoping that using a mixture of the instantaneous gas heater on better days and propex electric heater on the colder days and bit of clever plumbing should work, anyone with any clever ideas how to integrate them both please tell me

I would simply plumb the electric heater into the cold supply for the gas heater - switching on the electric heater in colder weather - this would allow cold water to simply pass through the electric heater in warmer weather.