Boiler overheated - now CH but no HW!

[TG]

Hi

Would really appreciate any advice!

We have a Worcester 280 RSF combi, about 11 years old, and the pressure reading has been becoming more unstable lately. I bled some air out of a radiator upstairs last week. The next day the pressure was almost zero so I topped up the system to about 1.5 bar. The next day the pressure had risen to over 3 bar with the heating on so I bled a lot of water out of a radiator to bring it back down to 2. This morning the house was very warm, the radiators boiling hot, the boiler casing was very hot to the touch and the pressure gauge read 4! (end of the scale). I had also run a bath that was stone cold.

I turned the boiler off straightaway and unplugged it from the electric supply. When it had cooled down I bled a radiator until the pressure read 1 bar. Now if the temperature is set at III the radiators aren't warm enough to heat the house but the pressure goes no higher than 2.5 bar. If I turn the temperature up to IIII to heat the house the pressure goes above 3 bar. (We replaced a long radiator with 2 small ones in Feb. but the system worked fine afterwards)

Also since last night the hot water, which was scalding, hasn't worked at all. When I put the boiler onto 'Water' and run a hot tap fully the boiler fires up but the water stays freezing cold. Even though the boiler seemed to overheat this morning I didn't have to reset it as it didn't cut out.

Before anyone says anything we couldn't afford to have it serviced - 4 years ago when we bought the house a Worcester engineer told us it was too old and becoming too corroded for us to have a maintenance contract without a major overhaul first. We're currently having to rely on disability benefits and we keep our fingers crossed through the winter! (We've been lucky so far...). Does anyone know how serious this sounds? I'm already having nightmares (literally) about the boiler exploding.

Thankyou very much (please be nice - I'm female !!)

 

[mark333]

Hi
most combis i have come across have a pressure relief valve that kicks in around 3 bar ,i would try to check that yours is working.If not you must have it replaced before any real damage occurs.
I know it's not what you want to hear but i would get the boiler change . b+ q are doing a good deal on raven heat condensing boilers .if you know a pensioner i think you get 10% off on wednesday's
Very cheap to run. Don't change the rest of the system if things are tight.And get a few quotes for fitting it.
But at the very least get an engineer to check the boiler out .
pS did you disconnect the filling loop after you filled the boiler the first time,if not you may not have turned the filling tap off fully.

 

[TG]

Thankyou so much Mark,

that explains alot - I think then that the damage has already been done from when the boiler overheated the other day as it managed to kill off the hot water. I'm keeping a careful eye on the pressure gauge and keeping the heating on low (I double-checked the filling tap, don't know where the excess water keeps coming from!).

Thanks for the new boiler tip - will find the funds ASAP so I can sleep peacefully again!

 

[ChrisR]

About the only thing amongst what you're describing which could make you have to have a new boiler would be corrosion, but it doesn't get that bad very often.
Your pressure problem may be just a question of pumping up the pressure vessel (with a car foot pump), and that could be the root of overheating problems too. If someone doesn't even try it then they aren't interested in getting the boiler going at all.
With this as a possibility it seems premature to condemn the boiler moribund.
Boilers are not as a rule damaged by overheating (ie boiling). They aren't that delicate.
Non-working hot water is a pretty standard fault, which needn't cost a fortune to mend on this boiler.

A new boiler may look attractive at say £550, but you're going to have to spend a lot more than that to get the work done to fit it, so it should cost far less to get your boiler fixed, from what we know so far.

The bad bit is that if there is a problem like your radiator system being full of rusty sludge which is contributing to your problems, that will have to be sorted out too. As it would if you had a new boiler.

So, yes you will have to spend some money on it, but it IS worth trying harder to get your boiler fixed. It would take some (payable) work to sort out exactly what's wrong with it, but then you should have a good idea of what full repairs would cost.

 

[mark333]

I do agree in part with Chris,but when you take into consideration the age of the boiler and the high efficiency levels of the new condensing boilers, the rising price of gas and future maintainance of the old boiler,the comments of the heating rep 4 years earlier, then any major cost's on repairing the old system would be better spent on renewing the boiler.
I currently pay around £200.00 for having a boiler replaced depending on how much work is involved
Hope this helps

 

[TG]

Thanks guys,

it's tricky but considering it cost us £200 4 years ago for a Worcester-Bosch engineer to replace a valve (and that was 2 visits!) I think we might somehow pay for a new boiler for the future than pay call-out charges to see how to fix the overheating, pressure and hot water problems, even though they might all be easy to fix, just because it is more than one problem to be fixed by the sounds of it.

To be honest this year the boiler has lost my trust!

 

[Agile]

Chris has been a little low key when he pointed out that in all probability all you need to do is repressurise the expansion vessel.

Unfortunately Mark is clearly not a professional and is blissfully unaware of the likely problem. Some would say definately not a professional when he recommends a Ravenheat !

If you search of some of the posts on this or other sites you will learn how to repressurise the vessel which takes about 15 minutes and only needs a step ladder and a car foot pump.

Its the knowledge which makes a professional a professional!

Tony

 

[TG]

Thankyou - all taken on board, I'm a bit concerned it says elsewhere that you have to empty the water out of the boiler and bring the system to atmospheric pressure before you can pump up the expansion vessel.

I'm wondering now if my pressure problem could be with the filling loop - how do you disconnect it exactly? The tap's definitely off as far as it can go (no water sounds from it) and I just tried turning off what I thought was a cut-off valve above it with a screwdriver but it leaked water everywhere so I had to turn it back to 'on'.

Now every time I want to put the heating on quickly when the house is freezing cold I have to bleed a radiator to get the pressure down to 1 bar, after up to half an hour of the heating being on the pressure is 3 - 4 bar, so I turn the boiler off and when it's cool the pressure goes down to over 2 bar, ready for me to bleed the radiator again. (the water I bleed out of the radiators used to be light brown but now it's milky white with an oily film and smells of oil)

This can't be right - where's all the excess water coming from or am I bleeding the system dangerously dry somehow? help!

Also it doesn't matter now what temperature level I set the boiler at - it goes into overdrive anyway so I can't leave it unattended.

 

[Agile]

Chris has told you, I have told you, but you still dont want to take our advice!

Instead you have your own ideas! It makes me wonder why you asked in the first place if you dont want to take heed of what we tell you?

When you have done that we will tell you to disconnect the filling loop and see what happens then.

Tony

 

[TG]

Sorry Tony

I guess I am scared of re-pressurising the expansion vessel on my own - I keep going to and then think I'd better not! (on this forum some people say 'empty the boiler' and some say you have to empty the whole system, some say it is an easy job and others that you have to be really careful - didn't want to risk doing something that resulted in a flood or explosion, especially on a weekend). My husband will help me with it tomorrow and then I'll know how it affects the pressure.

In the meantime I was reading the manual to try and work out how extra water keeps getting into the system to increase the pressure too (the pressure doesn't go back down again when cooled). I've noticed that when the boiler's switched to 'water' only and I run a hot tap the radiators heat up and the boiler pressure rises fast even though the tapwater stays cold. The pressure stays high when the boiler cools until I bleed a radiator to bring it back down to 1 bar.

Will check the pressure of the expansion vessel tomorrow as you all suggested, thankyou. I'm sure that will help.

Sorry for jumping the gun - felt very cold and frustrated but too scared to play with the boiler on my own.

 

[Agile]

If you are ( lucky enough ) to have a husband then let him take charge of manly things like heating. You can be in charge of the kids and the kitchen!

Tell him to just relieve the pressure and repressurise the expansion vessel to 0.9 Bar on the foot pump. Keep it connected and use the filling loop to pressurise the boiler to 1.5 bar. See if the footpump gauge increases as well ( as it should! ).

If water is leaking into your system then its either from the filling loop or the plate heat exchanger is leaking. We will deal with that later.

If you husband is a vicar or solicitor or other practically useless occupation then you must take charge. Sri Lanka had a woman PM a long time age and we had Mrs Thatcher not quite that long ago! So women can do it if they want to.

I bought some new toilet seats and found them magically fitted at home when I returned the next day. ( When I am busy, she helps me to fit radiators but " feels tired" after only a couple of hours work! ) I may soon have a black female gas work experience trainee although I am waiting to interview her as my male trainee says she doesn't know much about gas. Perhaps I should wait to see if she has passed her CCN1

Tony Glazier

 

[TG]

Don't think I'll make PM but I'm getting pretty handy!!

My husband was great at DIY but has a brain injury so I have to do most of the thinking at the moment, but still feel braver when we tackle scary things together.

Will let you know how it goes...

 

[scatmanjohn]

Agile: Is that the most non PC post of all time.



Women know your limits!!!!!

 

[Agile]

Not really, although its rather tongue in cheek, read it again, its actually angled ( unjustifiably ) at supporting females doing things.

To anyone who is inclined to post rude replies, just ask yourself if you have ever had a black trainee or a female trainee or both together?

To TG ( my initials ), sorry to hear about hubbies injury ( stroke ? ). Dont be frightened about doing anything to your boiler, they are fitted with protective devices which will generally prevent any major calamity. Just get on with it and we will help you sort it out.

Tony

 

[scatmanjohn]

Agile...what is the difference between a black female trainee and a non black one.

BTW...i'm not being rude, just curious