power flush

[dotto]

Hi guys.
i changed location to 2 rads yesterday at a friend's house and after having refilled the system and fired the boiler, the boiler would only fire for a minute before switching itself off. I touched the pump next to the hot water cylinder and the pump itself was very hot and so was the boiler, but the pipes going into the cylinder and the ones feeding the central heating were cold. The boiler would only fire up again once the boiler had cooled down and there was a call for ch or dhw but only for another 30 sec or so before, again, switching itself off. All rads have been bled.The system is an open vented system and the boiler is a Potterton but i can not remember its model. I must say that when i emptied the system to remove the rads to change their location, the water was very dirty, even after a second flush. Since this friend has a policy with BG, he called them in this morning and they said that he needs a power flush or change the boiler. The boiler was working perfectly fine before i changed location to the rads and even if he wanted to go for a new boiler he would still have to flush the system before fitting the new boiler anyway. The guy does not have enough money to hire a power flush machine so my question is do you have another idea as to how to flush the system?I wanted to buy a Fernox and flush the system with it but as i said, the system only fires up for a few sec before switching itself off so i don't see much of a point in adding it to the system. Sorry for the long post and thank you very much for your time.

 

[kevplumb]

you have checked the pump is running and bled it

 

[dotto]

you have checked the pump is running and bled it

Thanks for answering m8. Yes, I removed the screw from its face and i could see the impeller spinning.

 

[jay1]

was there any water coming out of the pump when you have bled it

 

[dotto]

was there any water coming out of the pump when you have bled it

Hi jay1 and thanks for your reply. Very little water came out (black) and the impeller was spinning.

 

[dotto]

was there any water coming out of the pump when you have bled it

Hi jay1 and thanks for your reply. Very little water came out (black) and the impeller was spinning.

Do you think i could connect up a hose pipe to the drain off cock just under the boiler and flush it with mains pressure? I would shut off the gate valve on the feed pipe and put a push fit stop end on the vent pipe to prevent water flooding the loft and would also connect a hose pipe to the lowest rad drain off cock running the hose pipe into the back garden to relieve some of the pressure when the system fills up? Would that be too dangerous or feasable? or there is a risk of the boiler not being able to withstand mains pressure?

 

[holty]

its basically somthing i do if not powerflushing.besides. there shouldnt be a gate valve on the cold feed from the f&e though.what i do though is close all rads except one.then close that off with another open.basically one by one your fushing the rads through.

 

[dotto]

its basically somthing i do if not powerflushing.besides. there shouldnt be a gate valve on the cold feed from the f&e though.what i do though is close all rads except one.then close that off with another open.basically one by one your fushing the rads through.

Thanks holty 4 your reply. I know but there is indeed a gate valve on the feed which i will have to close to flush the system i believe. In your experience, do you think i would not damage the boiler like that? Is it ok to leave the doc on the lowest rad on the system open to relieve the pressure? Is there anything else i should be aware of before i get on with it? Thank you for your time.

 

[dotto]

its basically somthing i do if not powerflushing.besides. there shouldnt be a gate valve on the cold feed from the f&e though.what i do though is close all rads except one.then close that off with another open.basically one by one your fushing the rads through.

Thanks holty 4 your reply. I know but there is indeed a gate valve on the feed which i will have to close to flush the system i believe. In your experience, do you think i would not damage the boiler like that? Is it ok to leave the doc on the lowest rad on the system open to relieve the pressure? Is there anything else i should be aware of before i get on with it? Thank you for your time.

Is it also ok to leave the pump in place or should i remove it?