Hot Water problems

[domroe]

Hi, hope someone can help.

I have a old Potterton Puma 80. Hot water was a problem when we moved in. Hot for about 30 seconds then cold again then hot and so on. The Gas valave was replaced a couple of weeks ago and that solved the problem constant hot water.

The problem has started happening again. When the hot tap is switched on the burners fire up but 25 seconds later go off, then 25 seconds later the come back on again. Heating works fine by the way.

Any ideas ?
Cheers Dom.

 

[chrishutt]

The Gas valve was replaced a couple of weeks ago and that solved the problem ........ The problem has started happening again.

It obviously didn't solve the problem. You have paid for an unsuccessful and unnecessary "repair". I believe these boilers have problems relating to the wax thermostat. You should be able to find lots more info if you search the forum on Potterton Puma.

 

[domroe]

Thanks for that.

 

[Agile]

It was not the gas valve and its not the waxstat either! Thats obvious because of the nature of the fault.

The heat exchanger may be sludged up and overheating or there may be a similar effect caused because the pump is not running during hot water delivery. Thats often caused by a fault on the PCB which may be intermittent. The pump itself just possibility might be intermittent or seizing up when it gets hot.

You need a competent boiler engineer who does not change perfectly good parts to "see" if that cures it ( or not ). Call him back and get him to sort it out properly. He should refund the cost of the gas valve which is quite expensive but you will need to pay for a new PCB if he concludes its that at fault. I dont think he is clever enough though!

You should not have had to pay for his incompetence! You can name and shame him or take him to the County Court. Be aware that this is not such a straightforward boiler but if he lacks the competence he should not take on the repair.

Tony Glazier

 

[Baxmax]

Its worth a look see at the air pressure switch tubes to check for splits and cracks.If there is a slight split or crack in the tubes as the temp rises the "split/crack" if there is one will enlarge and cause the A.P.S to "drop out".Note this fault would not be as obvious in .C.H mode for obvious reasons.