no hot water but radiators on demand

[niftynarker]

i have a strange problem which has been going on for about a year. neither the gas board or ANY gas man can help. i have an old thorn housewarmer mark 11 backboiler. it flares to life for few mins then dies. im lucky if i get half a bath in 24 hrs, yet when i turn thermostat on for heating, the radiators come on and the back boiler will remain alive. the gas board say i need a new boiler (they might be correct) but say they cannot clear the sludge out of the pipes because of the way my drinking water is linked up to the mains (??) independant gasman says i need a new cylinder in the loft-everyone says different things. ok i need a new boiler eventually but if my radiators come on hot then why can i not have hot water? its a gravity central heating system they say.

 

[masona]

Do you have a motorized valve for hot water demand?

 

[niftynarker]

Do you have a motorized valve for hot water demand?

i am not sure about that. no-one has mentioned it to me and im not a techy person. will ask gasman.

 

[COG]

From the description you gave about the drinking water and unable to clean ! I would gues you had a primatic cylender this basicaly depends on an air buble seperateing the primary heating water from the secondary stored hot water ,so it cant be cleaned out with a pump or chemicals.if it is a primatic it should be on the cylender label plus you will only have one tank above the cylender instead of two in a fully indirect system.primatic cylenders are expensive to replace .

 

[niftynarker]

i recently posted about my old thorn back boiler-well today it's died for sure. no hot water or radiators at all. not a spark of life.
thanks for your help and comments but i've got a surveyor coming on friday to see if i can have a combi fitted.
my new question is: will a new combi work with the existing 20 year old pipework? if it doesn't i'm snookered.

 

[COG]

All your rad valves should certanly be changed as for the rads they should require flushing out after 20years worth of use on a cast iron boiler. new rads would be the true answer but if you cant you cant its your risk and you plumbers to some