Hot Water Issues - Please Help

whitelightrider

Ok folks, have some issues that I need your advice/help on. Have posted before about some of these issues.

We have a 300l solar cylinder housed in the garage 90ft from the house with a pumped system for the hot water. There is also a 3kw immersion on the cylinder.

First question - The water was heated from 7am to 8am this morning via the boiler. At 5pm this evening the water in the tank was stone cold. Should the water in the tank not be at least warm? The only hot water used all day was to fill a sink to wash some dishes.

Second - Last time we tried the immersion it took 4 to 5 hours to get the water warm, not even hot. 2 separate plumbers told us that it was mad and should only take 20 to 30 minutes. My sister has an ordinary 300l cylinder and it only takes 20 mins for them to heat enough water for 2 long showers. Is is correct for ours to take so long to heat up? Immersion is on the bottom 1/3 of the tank. It would be worth changing out our solar cylinder for a standard cylinder if its going to heat in 20 mins as opposed to 4 hours.

We do not have solar panels yet but thought we'd future proof the house by installing a solar cylinder.

whitelightrider

According to the site below, the heat up time from cold to 65 degrees is 40 minutes. Is this also true from immersion or is it just from the boiler?

http://www.heatandplumb.com/acatalog/Telford_Tempest_Indirect_Unvented_Cylinders.html

If I wasnt already bald Id seriously be pulling my hair out.

liam300tm

has your plumber been back to look at it, something is seriosly a miss.

whitelightrider

liam300tm wrote: »

has your plumber been back to look at it, something is seriosly a miss.

Hi Liam. He's due back this week to take another look. He told me that it should only take about 40 mins to heat the tank from the immersion. Had the electrician in to take a look and all he did was turn on the immersion for 5 hours and hey presto we had hot water. Twit. Im going to get both of them in together to take a look at it. All I know is that it doesnt sound right to me.

Borzoi

whitelightrider wrote: »

2 separate plumbers told us that it was mad and should only take 20 to 30 minutes. My sister has an ordinary 300l cylinder and it only takes 20 mins for them to heat enough water for 2 long showers. Is is correct for ours to take so long to heat up? Immersion is on the bottom 1/3 of the tank. .

1) Hmm, I assume the tank is insulated, then chances are it's never warmed up fully in the 1st hour, it probably needs 2-3hours, then once warm will stay warm. Only an hour a day is very little for a large cylinder

2)The immersion is usually the top element for showers, as you rarely need to heat the whole tank, just 15-20mins to get the hot water for showers etc. And the solar coil at the base - to allow the whole tank to heat.

Outkast_IRE

Ok here is what i reccomend

Heat the tank fully by whatever means , immersion or heating.
Then see how long it stays warm for.

At least then you have established how long your tank should stay warm.

I know of a few people complaining a bout the immersion in these large tanks, i tried to source a better immersion and was told somethin like you need 2 phase power for the best one !!!!!!
One thing about these tanks is if fully heated they should stay warm for a while so. your right somethin is seriously amiss here .
Does your system have a control panel where the heating can be set to heat hot water only ?? if so then turn it on to that setting and see how long it takes then

sinnerboy

The full 90 foot long primary pipework is highly insulated i take it ? No damage at all to the insulation ?

sinnerboy

By looking here and playing with Excell - it should take over 6 hours to raise the tank from 5 degrees to 65 degrees

Or half that time to heat half the cylinder .... ball park

http://www.laundry-and-dishwasher-info.com/Power-and-Heat.html


Calculation of the Amount of Power to heat Water.

Using The Formula*Q=MC(t2-t1) in KW

Q (KW) = KW

M=Kg per Second Mass =Litre/60 * minutes

t2-t1=Temperature Increase °C = 60.00°C

C= Specific Heat of Water (A Constant)(4.18) = 4.18


Cylinder Time M C T2 T1 Q
Litres minutes Kg/psM SHoW °C °C KW
300 400 0.0125 4.18 5 65 3.135

hours
6.666666667

( sorry the format messes up here when i cut and paste )

sinnerboy

Cylinder Time M C T2 T1 Q
Litres minutes Kg/psM SHoW °C °C KW
45 60 0.0125 4.18 5 65 3.135

hours
1

again hard to read here - but formula indicates that for 1 hour of immersion you get 45 litres of water raised from 5 - 65 degrees . In the tank . Before the 90 foot dead leg is run off . If that is properly insulated .

Sounds like a fundamental design flaw .

Outkast_IRE

a 90 ft run ideally needs a hot return doesnt it

sinnerboy

Well put is this way

If the primary pipework is 40mm diameter- it holds 37 liters . At 15 litres / minute shower rate will take just over 2 minutes to run it off

Then as calculated above .... for 1 hours immersion- you can have a 3 min shower .

OP - there may be nothing wrong with the workmanship of your installation - but who designed it ?

whitelightrider

Ok folks,

Just to answer a few questions:

1. the tank itself is insulated. Its a Tempest Solar Tank.

2. The plumber designed the system and tells me that the pipe from the garage to the house is insulated. Anyway even if it wasnt surely the water in the tank should stay hot?

3. The water was heated at approx 8am and no water was used all day. At 5 or 6pm the water was stone cold when the shower was run. There is a pump pushing the water from the tank into the house so surely it shouldve stayed at least lukewarm?

4. The sister has a 300l tank also (not solar) and it takes 20 mins immersion power to get 2 normal hot showers. I dont know where her immersion is but ours is at the bottom third of the tank. I mean Id rather shell out for a new tank like hers and have hot water than have an immersion that cant heat the tank at all.

Carlow52

sinnerboy wrote: »

Cylinder Time M C T2 T1 Q
Litres minutes Kg/psM SHoW °C °C KW
45 60 0.0125 4.18 5 65 3.135

hours
1

again hard to read here - but formula indicates that for 1 hour of immersion you get 45 litres of water raised from 5 - 65 degrees . In the tank . Before the 90 foot dead leg is run off . If that is properly insulated .

Sounds like a fundamental design flaw .

IMO the above 1 hr calc will only work if u have a 45/50l tank : I accept the math but not the result unless the tank was v well stratified and the element at top but 1 hr of a 2 or 3kW immersion in the bottom 1/3 of a 300l tank will yield no 60 degree water.

It seems to me that based on all the threads on this topic that I have contributed thus far:

OP refuses to accept that the heating time with the immersion is a 6hr + job

He sets more store on the plumbers views than the cold logic of the math done here by both SB and me, to name just 2

My final observations on this are:
1: is the immersion actually working?
2: is the tank stat actually letting it work?
2: is there a leak in the system?

mick2907

Hi
Heres my personal experience with a geo air to water heat pump. I would think the DHW heating is the same.
You have a 300L tank-
1. what is the size of the coil area going through the tank, is the hot water going through your coil in the tank long enough to heat your water? Is it suffiecent to give you 60-65Deg C of hot water? his was one of the problems I had the inner coil was to small for a 300L tank. It should be 3.15m sq or bigger. I had a 1.5m Sq coil through my DHW tank and it seemed to be always calling for heat
2. Can you monitor the temp of the water and the return temp from the DHW tank?
3. Are you heating anything else from your solar panels? Is there heat loss here.

I am in the Virginia area of County Cavan and in my opinion I was blinded by the plumber. He filled me with Bu--sh-t to sell the heat pump and now wants nothing to do with it. But that is ony my opinion. Best of luck with your DHW & solar panels, I am going back to a condensing oil boiler cheaper to install & cheaper to run.
Cheers
Mick

sinnerboy

Carlow52 wrote: »

IMO the above 1 hr calc will only work if u have a 45/50l tank : I accept the math but not the result unless the tank was v well stratified and the element at top but 1 hr of a 2 or 3kW immersion in the bottom 1/3 of a 300l tank will yield no 60 degree water.

No argument between thee and me C52 - The element should be at the top

OP if the flow rate is 10 l/min then the dead leg run will take 4 minutes

Where is your sisters cylinger located ? if its in the house then the starting temp would be higher - say 15 degrees

Then....
20 mins at 3kw will give 20 litres raised from 5 to 65 degrees - mixed 50/50 with cold to give - 2 no 4 min showers

whitelightrider

Hey guys,

Im sorry if it seems like Im disputing the maths here. Thats not what I meant. To be honest Im not a plumber and dont know anything about plumbing. All I know is that our tank is a 300l Tempest Solar Tank running from a condensing boiler with no solar panels installed. There is approx 90ft of a run from the house to the garage.
The immersion seems to work - the electrician turned it on and left the house. I came home 5 hrs later and the water was hot.

First problem I have is that even this morning the water was on from 7am to 8am via the boiler. I turned on the hot water at 10am and it was warm\hot but not roasting hot for a shower. Is that a problem with the tank we have?

Also the immersion. Its at the bottom third of the tank. Its 3kw but Im not 100% sure its doing its job. Ive had 2 separate plumbers into the house and they both have said that it should only take 20 - 40 mins to heat the water for showers. My sister cylinder is inside the house so obvioulsy a shorter run. But should the immersion not heat the water in the same way? I mean if its the tank thats the problem then Id get rid of it and get a similar one to what they have.

sinnerboy

Well - don't know what rating your boiler is - but lets say it is 20kw

In 1 hour this would raise your tank from 5 - 65 degrees - all 300 litres .
The cylinder will start losing heat after the boiler times out - but not so much after only 2 hours . Now , I estimate you are also "storing" 12.5% again in all that 90 foot run - which won't be heated by the boiler and which will take 3-5 mins to run off

Assuming you did run off and still only got warmish water - is there a stat on the cylinder which cuts off the cylinder from the boiler - and if so what temp is it set to ? It should be set to min 60 degrees - max 65

I don't think the cylinder is in itself "to blame" . A stat setting or "sticky" motorised valve would be my suspects

.

Borzoi

whitelightrider wrote: »

Also the immersion. Its at the bottom third of the tank. Its 3kw but Im not 100% sure its doing its job. Ive had 2 separate plumbers into the house and they both have said that it should only take 20 - 40 mins to heat the water for showers. My sister cylinder is inside the house so obvioulsy a shorter run. But should the immersion not heat the water in the same way? I mean if its the tank thats the problem then Id get rid of it and get a similar one to what they have.

http://www.telford-group.com/downloads/Installguide_tornado.pdf

Full install guide above - immersion is shown at low level. As others have said, (people with maths skills, not plumbers) just using that immersion at that level, it's a 6 hour job to heat a full tank to 60C. IMO that's a crap design.

Looking at the install guide, they have a heat up time using the boiler coil of under an hour - but thats a 17kW load (by my calcs - and I am a HVAC engineer) so it's possible in the morning that your boiler is just not capable of heating all the rads/UFH and the whole cylinder. Check it out by closing the heating system, and just trying to heat the water tank

whitelightrider

sinnerboy wrote: »

Well - don't know what rating your boiler is - but lets say it is 20kw

In 1 hour this would raise your tank from 5 - 65 degrees - all 300 litres .
The cylinder will start losing heat after the boiler times out - but not so much after only 2 hours . Now , I estimate you are also "storing" 12.5% again in all that 90 foot run - which won't be heated by the boiler and which will take 3-5 mins to run off

Assuming you did run off and still only got warmish water - is there a stat on the cylinder which cuts off the cylinder from the boiler - and if so what temp is it set to ? It should be set to min 60 degrees - max 65

I don't think the cylinder is in itself "to blame" . A stat setting or "sticky" motorised valve would be my suspects

.

Ill have to check this when I get home later and will post up. Im getting the plumber and the electrician back again to take a look at the setup. If its the cylinder thats badly designed then I want to get a new one that will meet our requirements. Im not shelling out for a tank thats badly designed and not doing what we need.

sinnerboy

Just noticed that this is your 3rd thread on the same subject

So far you have been told several times by several posters that

That a 3kw input will take between 6-8 hours to heat your cylinder
That the immersion is better located at the top
That a 20kw input will heat the cylinder in 1 hour
That a stat setting is probably your problem

Changing the cylinder will achieve nothing .

whitelightrider

sinnerboy wrote: »

Just noticed that this is your 3rd thread on the same subject

So far you have been told several times by several posters that

That a 3kw input will take between 6-8 hours to heat your cylinder
That the immersion is better located at the top
That a 20kw input will heat the cylinder in 1 hour
That a stat setting is probably your problem

Changing the cylinder will achieve nothing .

sinnerboy, this is not the third thread on the same subject. My other thread is regarding installing an electric shower in the house that has not been plumbed for it.

Also on your point, yes I know what I have been told and I take each of their points. I understand that the cylinder will take 6-8 hours to heat the cylinder with the immersion on the bottom of the tank. Can it be moved to the top? If not then its not much good and needs to be replaced.

Can you tell me where the stat may be located that might be causing the problem?

sinnerboy

http://www.boards.ie/vbulletin/showpost.php?p=59368673&postcount=4

whitelightrider

sinnerboy wrote: »

http://www.boards.ie/vbulletin/showpost.php?p=59368673&postcount=4

Checked that already and its set at 60 degrees if my memory serves me. Its the factory default. This is about 1/3 from the bottom of the tank.

sinnerboy

http://images.google.ie/images?gbv=2&hl=en&ei=lMbtSe2HHpSPsAbplvz6Bg&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=cylinder+stat&spell=1

located close to cylinder looking like one of these

WLR - I hope you get sorted soon

whitelightrider

sinnerboy wrote: »

http://images.google.ie/images?gbv=2&hl=en&ei=lMbtSe2HHpSPsAbplvz6Bg&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=cylinder+stat&spell=1

located close to cylinder looking like one of these

WLR - I hope you get sorted soon

Me too SB. Could end up being a very short marriage!! Shouldve just installed an electric shower at the time!!

MickLimk

Been away from boards for a while but do remember your previous thread on this same subject. I am a solar installer and here are a couple of facts:

The two separate plumbers that looked at this system and told you the immersion should heat the cylinder in 40-50mins are clowns. I can't understand how someone could call themselves a plumber and not know about water stratification and how water heats.

At this stage you have been given the true heating times by a couple of people, both in this thread and in your previous one. These heat times are facts based on the laws of physics, not disputable opinions but facts. If you don't believe the laws of physics, then post over in the paranormal section!

The cylinder you have is designed for solar as you know. It is a well designed product when used for the purpose it was intended. Depending on the overall installation, the ideal location for an immersion in a solar cylinder may well be at the bottom. The reason in this case is that the immersion is supposed to be used only to heat all the water to temperature on occasions of prolonged low solar input to kill off Legionnaires. A cylinder with an immersion at the top cannot heat the water at the bottom of the cylinder where it's most needed to provide this function.

With the Tempest cylinder you have you will not be able to move the immersion to the top as it's not designed with a boss to take an immersion in that location. In an ideal world based on how you are using your current system you would have gotten a cylinder with two immersions, one at the bottom and one nearer the top. I have seen these in a triple coil before but can't locate one at the moment.

I really believe that your problem is not related to how the water is heated but what is happening to the hot water once heated. It would be a shame to spend €1k+ on a new cylinder only to find that you still have the same problems with your hot water disappearing. Your 90m run of pipework may have something to do with it but it could equally be related to a configuration issue with a pump. Any chance you could post a few photos of your setup? Might be possible to spot something however unlikely.

Whereabouts in the country are you?

whitelightrider

MickLimk wrote: »

Been away from boards for a while but do remember your previous thread on this same subject. I am a solar installer and here are a couple of facts:

The two separate plumbers that looked at this system and told you the immersion should heat the cylinder in 40-50mins are clowns. I can't understand how someone could call themselves a plumber and not know about water stratification and how water heats.

At this stage you have been given the true heating times by a couple of people, both in this thread and in your previous one. These heat times are facts based on the laws of physics, not disputable opinions but facts. If you don't believe the laws of physics, then post over in the paranormal section!

The cylinder you have is designed for solar as you know. It is a well designed product when used for the purpose it was intended. Depending on the overall installation, the ideal location for an immersion in a solar cylinder may well be at the bottom. The reason in this case is that the immersion is supposed to be used only to heat all the water to temperature on occasions of prolonged low solar input to kill off Legionnaires. A cylinder with an immersion at the top cannot heat the water at the bottom of the cylinder where it's most needed to provide this function.

With the Tempest cylinder you have you will not be able to move the immersion to the top as it's not designed with a boss to take an immersion in that location. In an ideal world based on how you are using your current system you would have gotten a cylinder with two immersions, one at the bottom and one nearer the top. I have seen these in a triple coil before but can't locate one at the moment.

I really believe that your problem is not related to how the water is heated but what is happening to the hot water once heated. It would be a shame to spend €1k+ on a new cylinder only to find that you still have the same problems with your hot water disappearing. Your 90m run of pipework may have something to do with it but it could equally be related to a configuration issue with a pump. Any chance you could post a few photos of your setup? Might be possible to spot something however unlikely.

Whereabouts in the country are you?

Hey Mick,

Im based in Galway, Monivea area.

I know what youre saying in that the Tempest cylinder is designed for solar and not for the conventional way we are using it. However we did tell the plumber that we wouldnt be putting in solar until we could afford it.

We ran out of oil and the tank went cold. It took over 5 hours to get the water warm. Thats not something I can live with. Its bad enough now, and theres only 2 of us. What happens down the line?
Id rather spend the €1k on finding a way to install an electric shower into the house!! Unfortunately the plumber didnt leave any pipes leading to the attic. Not his fault as we never specified it.

Ill post pics of the setup tomorrow. At the minute everything is housed in the garage. The cold water is pressurised to the house using a Grundfos pump and the hot water is pushed through using a secondary return pump off the cylinder. The run is about 30m (90ft) to the house. Hot water is heated by a Firebird oil condensing boiler.

MickLimk

Sorry, meant 90ft alright, 90m would be a different kettle of fish!

whitelightrider wrote: »

hot water is pushed through using a secondary return pump off the cylinder.

Are you saying that you have a recirculating hot water system as mentioned previously by Outkast_IRE? This would be one of the first things to look at if so. Incorrectly set up, these could easily take all the heat from a cylinder especially without extremely well insulated pipework.

Otherwise a few pics will certainly help figure out how everything is connected up...

Joey the lips

Outkast_IRE wrote: »

a 90 ft run ideally needs a hot return doesnt it

I agree with outcase over this difference there is usually a hot return additionally is there a chance he has plumbed into the solar coil? which as far as I am aware is the top coil. My knowledge is not strong on this just trowing options

MickLimk

Joey the lips wrote: »

I agree with outcase over this difference there is usually a hot return additionally is there a chance he has plumbed into the solar coil? which as far as I am aware is the top coil. My knowledge is not strong on this just trowing options

Solar coil should always be the bottom one in a cylinder.

Firstly just to confirm reheat time with a immersion from cold to 65c is 202 minutes as per manufactures, not that i would be relying on a heat input similar to my kettle to heat 300 liters, the reheat time via your coil is 40 minutes as you know but that is only if your boiler flow temperature is at max 80c+, a lower flow temperature will effect reheat time of the cylinder, this type of cylinder should only lose 1-2 degree c over 24 hrs with no water drawn off, another thing to remember is you don,t have 300 liters of hot water when heating the cylinder vie the boiler coil as the cylinder stat will knock it off early because of it's position but you still should have enough water for a couple of baths. If it were me i would turn off the secondary return pump, turn up the boiler and cylinder stat to maximum which should then give a quick reheat time and the cylinder at it hottest with out using solar, i would then work back wards from there turning down the cylinder stat until i achieved the desired temperature, if after that you still have problems i would check the flow temperature from the boiler to the cylinder to confirm it's piping hot if so then your coil will transfer the heat in to the cylinder(as long as the stat is not defective) and your hot water has to be going somewhere ie... a leak, hope this helps, Gary.

whitelightrider

gary71 wrote: »

Firstly just to confirm reheat time with a immersion from cold to 65c is 202 minutes as per manufactures, not that i would be relying on a heat input similar to my kettle to heat 300 liters, the reheat time via your coil is 40 minutes as you know but that is only if your boiler flow temperature is at max 80c+, a lower flow temperature will effect reheat time of the cylinder, this type of cylinder should only lose 1-2 degree c over 24 hrs with no water drawn off, another thing to remember is you don,t have 300 liters of hot water when heating the cylinder vie the boiler coil as the cylinder stat will knock it off early because of it's position but you still should have enough water for a couple of baths. If it were me i would turn off the secondary return pump, turn up the boiler and cylinder stat to maximum which should then give a quick reheat time and the cylinder at it hottest with out using solar, i would then work back wards from there turning down the cylinder stat until i achieved the desired temperature, if after that you still have problems i would check the flow temperature from the boiler to the cylinder to confirm it's piping hot if so then your coil will transfer the heat in to the cylinder(as long as the stat is not defective) and your hot water has to be going somewhere ie... a leak, hope this helps, Gary.

Hi Gary, thanks for the advice above. Im getting the plumber back next week to go through everything with me. I cant see a stat on the cylinder. Ill take photos of the setup tomorrow and post them here.

Im also left with a bit of a problem in that the cylinder is designed for solar, as was pointed out here, and I cant afford panels. The plumber knows this and also knows that I need an immersion that works in less than an hour, not one that takes 5 or 6 hours to heat.
So should I ask the plumber to change the cylinder for a standard cylinder with the immersion at the top?

Have a look at http://www.telford-group.com/downloads/brochure_stainless.pdf and http://www.telford-group.com/downloads/Installguide_tornado.pdf for more info. There should be nothing wrong with your cylinder if it's heated by your boiler(untill you fit your solar) if all the controls are in place and working, if you read the fitting instructions you will find all the info you need make sure it's fitted as per manufactures instructions for your own safety and if ever you have to make a claim (god forbid) i have yet to find a cylinder fitted correctly and most are fitted in a dangerous or substandard way:mad:. If you want to use immersions to heat your cylinder i would go for a direct cylinder which will have two 3 kw immersions but no coils and and a smaller sized cylinder if you want to change it for a immersion at the top i don't know any unvented like that only vented which will have different fitting requirements and you will lose your mains flow at the tap, Gary.

I would suggest fitting an additional small cylinder within the house.

Say 100litres or so, this will provide hot water in a couple hours using an immersion (or sooner if heating from the top).

Get the plumbing reconfigured so that the boiler heats the coil in this cylinder and the output of the solar cylinder (when connected to panels) can be switched in via motorised valves when available.

Good idea:o

whitelightrider

Im going to check the cylinder again today and see where the stat is on it. I couldnt find one at all when I looked during the week. Just the solar stats. Ill take photos aswell and post them.

I need to get this sorted so Ill check with the plumber during the week also. Either change the cylinder for one with 2 immersions or 1 at the top. If we wanted to have a bath then we'd need to plan it a day in advance!!
Either that or install an electric shower. Theres no tank in the attic or a pipe going into the attic. So we'd need the plumber to take a feed from a cold pipe and feed it into a tank in the attic. And then feed that into the electric shower!

whitelightrider

Ok, here are photos of the setup:

http://s687.photobucket.com/albums/vv238/gordokumite/?action=view&current=DSC00778.jpg
http://s687.photobucket.com/albums/vv238/gordokumite/?action=view&current=DSC00779.jpg
http://s687.photobucket.com/albums/vv238/gordokumite/?action=view&current=DSC00780.jpg
http://s687.photobucket.com/albums/vv238/gordokumite/?action=view&current=DSC00781.jpg
http://s687.photobucket.com/albums/vv238/gordokumite/?action=view&current=DSC00782.jpg

You have a boiler that can heat your cylinder in 40 minutes if set properly, it should only lose a couple of degrees in 24 hrs if you don't draw from it when it reaches temperature, if you are just using your immersion to heat this volume of water then this is not the system for you and you will have to rethink your requirements and explain it clearly to your plumber, i have a unvented cylinder with a longer run from my garage to my house and it works perfectly this is because it's set up properly with a large lump of heat on the cylinder flow to give me the quick reheat times, there is no reason other than set up or installation faults for your installation not to work, if i were you i would get the plumber to go over the controls with you to make sure you have as much heat as possible going in to the cylinder coil, if you have and you still don't have enough hot water or you have insufficient heat going to the coil then go back over the post as all the info you need to fault find is there. The stat to control the temperature in the cylinder is the plastic box with a circular knob with a white wire coming out of it, set this to maximum until you sort out your problems and then turn it down again once things get to hot, good luck, Gary.

whitelightrider

gary71 wrote: »

You have a boiler that can heat your cylinder in 40 minutes if set properly, it should only lose a couple of degrees in 24 hrs if you don't draw from it when it reaches temperature, if you are just using your immersion to heat this volume of water then this is not the system for you and you will have to rethink your requirements and explain it clearly to your plumber, i have a unvented cylinder with a longer run from my garage to my house and it works perfectly this is because it's set up properly with a large lump of heat on the cylinder flow to give me the quick reheat times, there is no reason other than set up or installation faults for your installation not to work, if i were you i would get the plumber to go over the controls with you to make sure you have as much heat as possible going in to the cylinder coil, if you have and you still don't have enough hot water or you have insufficient heat going to the coil then go back over the post as all the info you need to fault find is there. The stat to control the temperature in the cylinder is the plastic box with a circular knob with a white wire coming out of it, set this to maximum until you sort out your problems and then turn it down again once things get to hot, good luck, Gary.

Hi Gary, cheers for that. Can you tell me what kind of cylinder you are using? I think the biggest problem with my setup is that the immersion is at the bottom of the cylinder and not at the top, where we need it to be. The white box is set to 90 degrees at the minute and I think the boiler is set to 65. When we ran out of oil the water in the tank didnt stay hot/warm after about 4 hours.

sinnerboy

WLR - I assume you had rads on for this 4 hours - if so that's where the heat went - on your space heating

whitelightrider

sinnerboy wrote: »

WLR - I assume you had rads on for this 4 hours - if so that's where the heat went - on your space heating

Hiya Sinnerboy. No rads. Only thing that was on at the time was the underfloor, so that may have taken the heat. But that just proves that we need to get a cylinder with an immersion at the top so that we could get enough hot water to at least shower.

sinnerboy

Yeah - after 4 hours of immersion your water would be raised to approx 30 -35 degrees - if no heat demand was being made . But the UFH will have been drawing the heat away all along so you would not sense any heat from DHW

It sounds like the plumber forget your intermediate phase - i.e. your system should be fine when completed ( solar panels in ) but in the meantime - no boiler = no hot water

whitelightrider

sinnerboy wrote: »

Yeah - after 4 hours of immersion your water would be raised to approx 30 -35 degrees - if no heat demand was being made . But the UFH will have been drawing the heat away all along so you would not sense any heat from DHW

It sounds like the plumber forget your intermediate phase - i.e. your system should be fine when completed ( solar panels in ) but in the meantime - no boiler = no hot water

I think so too. We did go through the future proofing by having the solar cylinder in, but that we couldnt afford it at the minute, and probably for a few years so we needed an immersion that worked.
Ill call him again today and talk to him about getting a cylinder with an immersion at the top of the cylinder.

whitelightrider

whitelightrider wrote: »

Hi Gary, cheers for that. Can you tell me what kind of cylinder you are using?

I have similar set up except 180 ltr cylinder with the flow to the coil being 80+ degree C, i keep the cylinder stat on max storing the water at a higher temp so i need less of it, the immersion works well as there is less water to heat when i have used it (all my oil was stolen) and the reheat time is very quick(with boiler), i have two showers and a big bath and have never ran out of hot water with the boiler on.

whitelightrider wrote: »

I think the biggest problem with my setup is that the immersion is at the bottom of the cylinder and not at the top, where we need it to be.

I think your problem is insufficient heat to your coil from the boiler, the higher you can get that the better the cylinder will perform so try turning up your boiler stat, as you have under floor heating there should be enough heat for the cylinder(25+kw output on the coil), turn off your heating and see what the temperature of the flow pipe in to the coil is, if it's still 65 degree C than that will effect performance, if it's 80 degree then the cylinder stat may be faulty and switching off before it should.

whitelightrider wrote: »

The white box is set to 90 degrees

If you turn up the boiler stat be careful as degrees C coming out of a tap would be brutal, try 75 for now but keep a eye on it if you have it higher.

whitelightrider wrote: »

at the minute and I think the boiler is set to 65

Again turn it up.

whitelightrider wrote: »

When we ran out of oil the water in the tank didn't stay hot/warm after about 4 hours.

If you get the tank up to a nice temperature, it should hold on to it, if not then pump on secondary return on to long or a leak on hot water draw off possibly.
As for the immersion on the unvented cylinder as far as i am aware there is no cylinder that has the immersion at the top other than a direct cylinder which has two immersions but no coils and are bloody expensive to run, if you are talking about a copper cylinder these cannot be used with the pump you have and you would have to fit a tank at the highest point of the house to feed the cylinder and as you have a long run i don't think it will work, have a talk with the plumber there is always a answer, Gary.

John mac

use the boiler to heat the water!

I don't even have an immersion, We just use the boiler, comes on for an hour in the morning and gives hot water all day.

all my rads have thermostatic valves so if the temp is above 17 they wont come on. (yea 17 thats plenty warm enough )

John mac

John mac wrote: »

so if the temp is above 17 they wont come on. (yea 17 thats plenty warm enough )

Please tell my wife that!!! :pac:

whitelightrider

I know!! My wife is sitting in the TV room now telling me she's cold, yet the stat behind her head is reading 19.1!!!

How hard would it be to put thermostatic valves on the rads? At present we have one stat on the landing to turn on the rads upstairs.

Ill have a chat with the plumber tomorrow. At present the boiler comes on for an hour in the morning, an hour in the afternoon and an hour in the evening. My only worry is if/when we run out of oil again.
Id like to put in an electric shower to cover this eventuality but the plumber didnt leave a pipe or tank in the attic. Could we continue the cold feed from the existing shower into a tank in the attic, and then feed that to an electric shower? The sparks already left cabing in there in case.

John mac

whitelightrider wrote: »

I know!! My wife is sitting in the TV room now telling me she's cold, yet the stat behind her head is reading 19.1!!!

How hard would it be to put thermostatic valves on the rads? At present we have one stat on the landing to turn on the rads upstairs.

Ill have a chat with the plumber tomorrow. At present the boiler comes on for an hour in the morning, an hour in the afternoon and an hour in the evening. My only worry is if/when we run out of oil again.
Id like to put in an electric shower to cover this eventuality but the plumber didnt leave a pipe or tank in the attic. Could we continue the cold feed from the existing shower into a tank in the attic, and then feed that to an electric shower? The sparks already left cabing in there in case.

just drain the system (upstairs) replace rad valves, refill system.

Could we continue the cold feed from the existing shower into a tank in the attic, and then feed that to an electric shower?

that should work

dont run out of oil! check the tank every couple of months,

whitelightrider

Trust me, the tank is being tipped about once a week anymore!!!

Could you give an estimate as to what it might cost to put in an electric shower?

whitelightrider

Deleted User wrote: »

I would suggest fitting an additional small cylinder within the house.

Say 100litres or so, this will provide hot water in a couple hours using an immersion (or sooner if heating from the top).

Get the plumbing reconfigured so that the boiler heats the coil in this cylinder and the output of the solar cylinder (when connected to panels) can be switched in via motorised valves when available.

Apologies for dragging up an old thread. My father in law mentioned this over the weekend. Would it be possible to fit a 100l cylinder with an immersion next to the existing 300l? If we need hot water and run out of oil we can switch on the immersion and have it heat the water in less time than its currently doing?