Ideal Mini - Gas Boiler - heating works but won't heat water?

justagirl · 16-09-2008 1:01pm #1

I have an Ideal Mini Gas boiler...We have it on a timer and use it to heat our hot water (and hot water and heating in winter)...There was no hot water this morning (the radiator/heating separate thermostat in the hall was turned right down to zero).... The boiler was timed to be on for about 4 hours but the water was cold... when I went down to check the boiler... it was working away but no lit flue light (not sure if this is the right word)... so I turned it off...

So, I turned the radiator/heating Thermostat on in the hall and turned on the gas boiler .....it lit up fine and heated the radiators... But then I turned off the radiator/heating Thermostat in the hall and the boiler loses its light (flue light? don't know what you call it)....

Its in for a service next week.... I asked my dad and he said it might have something to do with the electrical circuit?...

I'm flumoxed.... it heats the radiators but not the water ... Anyone? pls?:(

(the thermostat for the water is in my hot water cupboard - its up at 5)

crosstownk · 16-09-2008 3:34pm

It could be a problem with one of your motorised valves - it may be stuck or not working. Basically, if you do not need water heated the valve stops the supply of hot water from the boiler to the hot water cylinder. A similar valve controls the supply from the boiler to your radiator circuit.

So now you need to locate this valve - it's a box mounted to a pipe with an electrical cable attached. The valve should have a manual override lever which can move and lock in the 'on' position. If that solves the problem and your water heats, then you will need to ascertain if the valve itself is stuck or if is a wiring fault.

Another possibility is that a hot tap has been left on somewhere and the water is passing through the hot water cylinder too fast to be heated.

The motorized valve will look something like this > http://www.toolstation.com/images/library/stock/webbig/85125.jpg
The pic also shows the override lever.

justagirl · 16-09-2008 3:46pm

crosstownk wrote: »

So now you need to locate this valve - it's a box mounted to a pipe with an electrical cable attached. The valve should have a manual override lever which can move and lock in the 'on' position. If that solves the problem and your water heats, then you will need to ascertain if the valve itself is stuck or if is a wiring fault.

Thank you Crosstownk

Is this valve on the gas boiler or would it be in the immersion cupboard? .. Cant seem to see it near the boiler (need to find a torch:o)...Thank you so much.

crosstownk · 16-09-2008 3:54pm

justagirl wrote: »

Thank you Crosstownk

Is this valve on the gas boiler or would it be in the immersion cupboard? .. Cant seem to see it near the boiler (need to find a torch:o)...Thank you so much.

It could be anywhere - usually it's close to the boiler, but it could also be in the hot press. Two pipes are connected to the side of you hot water cylinder - try follow them - they both should return to the boiler - the valve will be mounted to one of them.

justagirl · 16-09-2008 3:57pm

crosstownk wrote: »

It could be anywhere - usually it's close to the boiler, but it could also be in the hot press. Two pipes are connected to the side of you hot water cylinder - try follow them - they both should return to the boiler - the valve will be mounted to one of them.

On the hunt now for the valve now..I'll have to find a torch..!... Thank you...

The water in the power shower in ensuite has gotten colder and colder in last month .. and is very cold (unusable!.. luckily we can use the main bathroom)... would that be linked in any way?

crosstownk · 16-09-2008 4:13pm

Is your boiler an Ideal Mini C or an Ideal Mini S? The letter should be on the casing followed by two numbers

More info here > http://www.idealboilers.com/docs/pdf/mini_users_guide.pdf

justagirl · 16-09-2008 4:37pm

crosstownk wrote: »

Is your boiler an Ideal Mini C or an Ideal Mini S? The letter should be on the casing followed by two numbers

More info here > http://www.idealboilers.com/docs/pdf/mini_users_guide.pdf

Its an Idea Mini S24....(it doesnt say that on the casing that I can see but says it on a Bord Gais Servicing invoice).

Sorry I still can't see that valve... I have to look again... It might be at the back of the boiler which is not too easy to see....

Thanks for link website... I'll have a look at it

crosstownk · 16-09-2008 4:40pm

If it's an S, which is a system boiler rather that a combi boiler, then it has to have a valve somewhere. In my last house the valve was fitted in behind the hotwater cylinder. In my current house I fitted them close to the boiler.

justagirl · 16-09-2008 7:03pm

Found it... I hope... it was in the immersion cupboard...it has a black cover and has a metal switch - when I pushed it forward ... it sounded like a little motor working and it just came back to the position it was in ....We pushed it forward into the little 'nook' for it to rest in (like in the picture you posted).... and I turned the heating thermostat off in the hall and put the gas boiler on... it fired up alright and lasted for about 10 mins till I turned it off....So do you reckon this is the problem?. What should I do now ? Would the valve be broken?

I've read the manual and it advises that the system water pressure gauge should be at least o,5 bar.... it was showing as slightly past 0 ... but when I did the above the bar pressure went higher (nearer to .)....

Thank you so much for your help.

crosstownk · 16-09-2008 10:05pm

OK - you've low pressure in the system - this is most likely why your shower's performance has deteriorated in the last while.

If the water in your cylinder is cold then I would imagine (I could be wrong here) that the boiler would have fired for more than 10 mins on an initial phase.

Next you need to locate the filling valve for your heating system. I'm assuming you have a sealed system. This means that water enters the system from you main water supply and cannot escape unless you have a leak or if you bleed radiators. The system is filled via a tap/valve. This may be located near the boiler and/or pressure vessel (a large, usually redish coloured cylinder).

If you locate the filling valve/tap, then open it while looking at the pressure gauge (or have someone else look at it while you open the filler valve). Only open it momentarily. Continue until the pressure reads 1.0 bar. Too little pressure is better than too much - so err on the lower side. The system pressure should only be read while filling when the system is cold.

Once you're happy that the pressure is correct, fire up the system and see what happens. You should be up and running as normal. If you are then reset the override lever on the motorised valve - let the system cool for a few hours and run again. Hopefully everything will be OK.

Some pics to help you identify things....

http://www.toolstation.com/images/library/stock/webbig/35419.jpg

http://www.h-i-e.co.uk/acatalog/RobokitExtra.jpg

The black 'tap' is the filler valve.

Hopefully you can make sense of that.

justagirl · 18-09-2008 12:30pm

Thank you so much for all of your explanations, help and advice Crosstownk - the pictures are very helpful ... I will do what you suggested at the weekend as I'll need some help and will post back.

Thank you again-very much appreciated.:)

justagirl · 24-09-2008 7:01pm

Hi Crosstownk ....

Sorry for delay in replying ...We haven't been able to find the red cylinder type thing? I don't think we have one... ?

..Cant see it anywhere.not in utilty room or hot press room... .. also the black lever for the water pressure .... can only find one that looks like it in the hot press ... and it is already on... there is a lever underneath the gas unit but it is yellow and won't move... (is this gas?).... We've tried our best ... even with all of your help - which is very much appreciated... at least I know a bit more know ...

We have found when we push the moterised valve in the hotpress forward and lock it in the little notch ... the pressure on the gas unit rises .... but the gas unit keeps cutting out and relighting...

Have I missed something really obvious here?

I have the Bord Gais guy coming out tomorrow for a routine boiler check so at least I'll be able to tell him all I know

Thank you anyway Crosstownk....

crosstownk · 24-09-2008 7:56pm

justagirl wrote: »

there is a lever underneath the gas unit but it is yellow and won't move... (is this gas?)....

Yes - if it's in line with the 'flow' of the pipe then it is on/open. This lever only moves through 90 degrees - if the lever is 'across' the pipe then it is shut off/closed. This lever should be easy to move as it shuts off the gas supply - you may need it in an emergency. If it is stiff/stuck then you should bring this to the attention of the Bord Gáis engineer when he calls.

I had an instance a few years back where an electrician had inadvertently partially closed the gas tap resulting in low gas flow to the boiler. It took me ages to find it but it was the cause of poor heating.

Ask the gas guy to point out the filler valve so you'll know for the future.

As for the boiler cutting out and relighting, this is normal because the gas heats the water in the boiler to a certain temperature, when this temperature is achieved the boiler cuts out and the pump continues to pump the heated water around the system until it cools. When the water cools (as it's heat is given off to the hot water cylinder/radiators) the boiler reignites. The cycle continues for as long as the heating is turned on. After half an hour or so, the water in your hot water cylinder should begin to get hot as should your radiators if the room thermostat is turned up.

Let us know what the fault was.

justagirl · 25-09-2008 7:58pm

crosstownk wrote: »

Ask the gas guy to point out the filler valve so you'll know for the future.

As for the boiler cutting out and relighting, this is normal because the gas heats the water in the boiler to a certain temperature, when this temperature is achieved the boiler cuts out and the pump continues to pump the heated water around the system until it cools. When the water cools (as it's heat is given off to the hot water cylinder/radiators) the boiler reignites. The cycle continues for as long as the heating is turned on. After half an hour or so, the water in your hot water cylinder should begin to get hot as should your radiators if the room thermostat is turned up.

Let us know what the fault was.

Ok.. found out where the filler valve was - its in the immersion cupboard - it was turned on already, so I assumed it wasn't it because it was on and it should have been off :rolleyes:....

The problem was the thermostat on the water cylinder - it was broken !!! I never noticed it.. to be honest, the dial turned so I assumed it worked. Fair play to the Bord Gais guy he showed it to me and showed me how to fix it back on when I buy a new one... so all I need to do it pick one of those up and install myself... I would have never touched it myself-I didn't realise it was such a simple device....

So I've learnt a hell of a lot! Thanks again for all of your help - very much appreciated.

crosstownk · 25-09-2008 8:23pm

You'll get a replacement in from any decent heating/plumbing supplier.

I usually use C&F Quadrant or Heat Merchants. Heat Merchants have an online catalogue so it's probably a better site to use.

I'd imagine you're looking for something like this.

Your faulty cylinder stat should have been by-passed by manually setting the lever on the motorised valve.

justagirl · 25-09-2008 8:43pm

crosstownk wrote: »

You'll get a replacement in from any decent heating/plumbing supplier.

I usually use C&F Quadrant or Heat Merchants. Heat Merchants have an online catalogue so it's probably a better site to use.

I'd imagine you're looking for something like this.

Your faulty cylinder stat should have been by-passed by manually setting the lever on the motorised valve.

Thanks for that Crosstownk.... maybe we didn't leave the gas on long enough to heat the water when we forced lever on the motorised valve?.. When we did this the gas kept cutting out?..

Re the thermostat: The one I have is very different to the picture.... it has a long metal thingy that you tape to the cylinder... from that is a spiral type metal strip which goes into the thermostat - something like what goes on top of pipes that come out of the floor alongside radiators... except it has a dial on top .. from 1-5......

Its so good to have heating AND hot water...... makes up for this official 'recession' we are in !!

crosstownk · 25-09-2008 9:01pm

The one in the link above is strapped to the cylinder and will do the job. Essentially, a thermostat is only a switch that turns off the boiler at the desired temperature.

I alway use Honeywell controls as I find them very reliable. That said I'm going with a Sunvic 3 channel programmer/timer as Honeywell don't seem to do 3 channel. I want a separate thermostat for the heating upstairs. But all the stats and valves will be Honeywell. That Honeywell cylinder stat is only €39.30 from Heat Merchants.

justagirl · 14-10-2008 7:40pm

crosstownk wrote: »

You'll get a replacement in from any decent heating/plumbing supplier.

I usually use C&F Quadrant or Heat Merchants. Heat Merchants have an online catalogue so it's probably a better site to use.

I'd imagine you're looking for something like this.

Your faulty cylinder stat should have been by-passed by manually setting the lever on the motorised valve.

Hi Crosstownk - thank you so much for your help to date...

The control is the Danfoss RAVI code number 013U801300 ...picture attached below...

so far Heat Merchants, Hevac, Davys and Heat Stores don't stock it....

arghhh!!...I've contacted Danfoss in the UK who told me it should be in any plumbers merchants..!!! .... the search goes on !!!!

Update: just had a look on Heat Merchants:http://www.heatmerchants.ie/heat/index.html - is this the same thing ?... don't know what the 1.5M means ...

crosstownk · 14-10-2008 9:26pm

I'd say the 1.5m refers to the 'flying' copper lead that leads to the valve. Essentially it looks like a sort of thermostatic valve for a hot water cylinder (I could be wrong here). It's mechanical rather than electrical - up to now I had assumed that your system was electrically controlled so some of the information posted earlier is not relevant.

The Heatmerchants link doesn't link to the product, can you post the Heatmerchants catalogue number?

justagirl · 14-10-2008 9:35pm

crosstownk wrote: »

I'd say the 1.5m refers to the 'flying' copper lead that leads to the valve. Essentially it looks like a sort of thermostatic valve for a hot water cylinder (I could be wrong here). Essentially it's mechanical rather than electrical.

The Heatmerchants link doesn't link to the product, can you post the Heatmerchants catalogue number?

So would that mean the 'flying' lead would be 1.5 metres?...silly question?!..if so, not what I want!!...

The thermostat i want is mechanical (i was not clear on this)..... as it attaches onto a valve that has a little piston (this the right word?!).. on it and you can push it down/up and this is what determines the heat of the water...(hope this makes sense) ...the plastic thermostat is screwed onto this and the flying copper wire leads to a stick like thing that attaches to the cylinder and it is this that reads the temp and controls the piston up/down..... (apologies for terrible explanation! .. I'm learning as I go along!!)... If I went the electrical route I'd have to replace this valve that has the piston on it and then get someone to do the electrical bit for the new thermostat so I just want to try and do it myself ...if possible!

Sorry about that bad link ... Heatmerchants catalogue number is: 247069

Thanks...

crosstownk · 14-10-2008 10:12pm

I think you've got the hang of it!! That Heatmerchants item looks like it will do the job for you. If I'm not mistaken, the sensor goes into the cylinder so the cylinder may have to be drained before fitting the new valve.

The valve you're looking for is essentially like the valves on your radiators. The only difference being that it requires the 'flying lead' to connect the immersed sensor in the hot water cylinder to the valve.

justagirl · 15-10-2008 12:12pm

crosstownk wrote: »

I think you've got the hang of it!! That Heatmerchants item looks like it will do the job for you. If I'm not mistaken, the sensor goes into the cylinder so the cylinder may have to be drained before fitting the new valve.

The valve you're looking for is essentially like the valves on your radiators. The only difference being that it requires the 'flying lead' to connect the immersed sensor in the hot water cylinder to the valve.

Thank you very much Crosstownk!...

..

The sensor on the old one was just stuck to the outside of the cylinder with heavy tape?.. the guy that serviced the gas boiler said that was right and to just put the new one where the old one was and showed me where to screw on the plastic top with the dial on it...

Thanks for explanation ! ... that makes it simpler for me to understand !.....

Many many thanks - you have been so helpful.

miilly · 18-07-2010 6:36pm

hi there, i seem to be having a similar problem to justagirl, my sunvic timer in the kitchen will turn on fine when you put the radiators on, but nothing happens when i try to heat the water... any help you can offer on this would be fantastic (i tried following your advice already posted, but nothing works, the only thing i can think of is the motorised valve i cant switch it far enough over to the manual side, it does move slightly in the position on the left, not sure if this is an issue though) oh and i dont have an ideal boiler mine is a vokera

thanks

makanju · 24-11-2013 6:45pm

crosstownk wrote: »

It could be a problem with one of your motorised valves - it may be stuck or not working. Basically, if you do not need water heated the valve stops the supply of hot water from the boiler to the hot water cylinder. A similar valve controls the supply from the boiler to your radiator circuit.

So now you need to locate this valve - it's a box mounted to a pipe with an electrical cable attached. The valve should have a manual override lever which can move and lock in the 'on' position. If that solves the problem and your water heats, then you will need to ascertain if the valve itself is stuck or if is a wiring fault.

Another possibility is that a hot tap has been left on somewhere and the water is passing through the hot water cylinder too fast to be heated.

The motorized valve will look something like this > http://www.toolstation.com/images/library/stock/webbig/85125.jpg
The pic also shows the override lever.

I know this piece was written a while ago, but it has just been a blessing to me. Since yesterday, my heater only heat the water and not the radiator. I talked to a lot of friends and the suggestions given ranged from checking the heating switch, pump and bleeding. Unfortunately none of these worked until I checked your advise on this site and I looked for the valve which was connected to with my hot press. I reset the lever and start the boiler. Everything started working. This is to say thank you. You just saved me 92 Euro call up charges. You've made my day.

Ideal Mini - Gas Boiler - heating works but won't heat water?

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