very hot radiators

[stevej]

My first posting so hope you can help.
Our radiators have become very hot (70C) recently and I think the boiler has a slight kettling problem as it has started to make banging noises like the water is boiling when it switches off. The boiler is a myson olympic 38/50B about 18 years old and the system is an open one with a three way valve near the water cylinder. We have had the thermocouple replaced recently because it burnt out and the problems started shortly after this I think. The thermostat on the boiler is normally set just above 4. It goes off if I turn it between 1 and 0. What is the normal setting for the thermostat and does this control the temperature of the water flowing through the radiators? Other info that might be relevant is that I drained and flushed the system last year and filled it with an inhibitor. I also took one radiator (in the extension above the garage) off recently and flushed out some black sludge as it was not heating properly. The thermostat on the hot water tank is also set at 70C - is this a coincidence?. The system is serviced every year. I have now turned the thermostat on the boiler to 1 to see if that will cure the problem but advice on what the problem may be would be appreciated.

 

[oilman]

Your HW thermostat could be set at 55 to 60. It may have some effect on the radiator temperature if you have a 3 port mid position valve.

 

[stevej]

Your HW thermostat could be set at 55 to 60. It may have some effect on the radiator temperature if you have a 3 port mid position valve.

Thanks for this. I turned the hot water tank stat down to 60C. The radiators are now at 50C but I think this is more to do with turning the stat on the boiler down.

 

[oilman]

Boiler stat should be set to between 70 and 80.

 

[boxster]

it all depends on the term "BOILER"

if your talking about a gas boiler, the thermocouple has nothing to do with the problems. When i service and maintain gas boilers i leave the stat on for number 3. Make sure the boiler stat is set for number 3. You boiler stat also could be on its way out and not shutting off a the temp allowed. If your problem persits change the boiler stat this would cause the increase noise and temp.

this is based on a gas boiler problem.

your problem is a fault BOILER STAT!

 

[stevej]

Yes we are talking about my gas boiler. The stat on it has been set to 4 (with 5 the top setting) for teh past 12 years. When the boiler is on I have to turn it to less than 1 before it goes off. I now have it set to just above 1 and it appears to be working OK. I dont have a manual for teh boiler so I dont know what setting it should be on but I will take your advice and set it to 3 and see if the temperature of my radiators increases. My question is, does the stat on the boiler control the temperature of the water in the radiators or does it just stop the boiler getting too hot?

 

[stevej]

When I changed the boiler stat from 1 to 3 the temp of the radiators increased to 65C so I am turning it back down to 1 and hopefully the radiators will go back to 50C as 65C is too hot to touch. It looks therefore like the boiler stat is controlling the radiator temp. Perhaps my flushing the system out last year has increased the efficiency of the rads so I need a lower setting than I had before? My boiler is definitely making more noise though (not hissing but just a low gurgling and you can hear this through the radiators). Since turning the stat down there is also no banging noise (from above the hot water tank in the airing cupboard) when it shuts off.

Should I leave the system as is or call in my heating guy?

 

[Potterton Man]

The thermostat on your boiler ranges from 55 Oc On min To 82 Oc om max allow aprox 5 Oc either way yuse a thermometer digital on boiler flow to check

 

[boxster]

to be honest when i service boilers and see it on number 4 i turn it to nmber 3. number 3 is a good number. By leaving it on 4 can cause this problem. however change the stat and your back to normal again. The banging you were hearing was the vent discharging water into the tank at least you have got shot of any air lol

If you replace the stat you can set it to number 3 and it would be the same as your current stat working at number 1.
you may still get the hissing noise as it might have damaged the heat exhanger but dont worry 70% of all the jobs i have been on have some sort of hissing noise its the heat exchanger on its way out, even boiler a few year old have this if the stat has been ran on the highest setting.

what is the model of you boiler and i own gasinstructionns.com i can send you a copy of the user instructions out free if you wish or you can download them and print them off. Its normally a charge but i dont mind doing it for free


Also i knew something was ringing in my ear about your boiler you better go to the link below: As we have converted these before...

Also check your case seal look for a seal round the boiler red or white you should see something bulging out if you cant get a engineer asap

see this

is your boiler BF? if it your ok.

 

[ChrisR]

gasinstructionns.com don't work? Neither does
gasinstructions.com

 

[boxster]

dam it was down, try it now!

may be back up in a around an hour, it should link to my site where it should link off, but i have had to move all my sites over and the links arnt working please you pointed it out..

 

[breezer]

still down

 

[stevej]

Thanks BOXSTER for this. There is a red seal around the boiler. How do you tell if it is BF ( I assume you mean balanced flue?). The boiler is in the garage and vents directly through the outside wall. It gets serviced every year so I think we should be OK. We've been here since 94 so I doubt if the boiler has had the recall work done on it. I've got the stat set on number 2 now as our hot water didnt get hot enough when it was on number 1. Our rads are about 60C now which is a compromise.

Website still not working but I got to gasinstructions.com and I got a message saying that my IP address had been taken which I havent seen up to now on any other sites I've been to.

I'll keep my settings as they are now and wait until the boiler packs up before I replace anything.

 

[boxster]

yer ip logged is nothing it stop CREDIT CARD FRAUD. we can problems a few years back with people using stolen credit cards its kind of DONT DO IT thing. As we sell from the site your i.p is recored WHEN and only when a transaction is made so if the credit card is stolen we have a comeback.

nothing to worry about tho mate

as to your boiler on the heat exchanger it will have a LARGE metal tag saying:

THIS BOILER WAS UPGRADED ect.. you cant miss it. however BF boiler are ok anyways. I assumed it was not for some reason ..