Venting boiler

[Terry1234]

take the srew out marked bleed and place a small screwdriver in and see if the shaft turns freely

Thanks for this i will check tonight and let you know the outcome. Thanks for the advice, the help is appreciated

I checked this and all seems free, any other advice?

 

[Terry1234]

Sorry but 80,000 btu and only 4 rads and you want to run the boiler on full ? ?

4 rads have been added there are 9 rads in total (including the new ones)

 

[Gasman1015]

He may have got the flow and return connections wrong when adding the other radiators, and I don't mean by just reversing them.

 

[ChrisR]

CLose the four which are working OK and you might push out an airlock stopping the others from heating.

 

[Terry1234]

CLose the four which are working OK and you might push out an airlock stopping the others from heating.

If i close the other ones of the remaining rads do get hot, but i have bled about 20ml of water from each rad and there does not seem any air in them, i have also bled the pump and opened the bleed valve in the airing cupboard by the pump, but to no avail.

Some one mentioned to me it's because i have microbore piping but it was working o.k before. (the new piping is hep2o going to microbore at the rads)

 

[Terry1234]

He may have got the flow and return connections wrong when adding the other radiators, and I don't mean by just reversing them.

How would i rectify this?

 

[Terry1234]

Thanks for all your help so far, the original pump on the system was free but i thought i would change it just in case, this has made no difference

 

[ChrisR]

If i close the other ones of the remaining rads do get hot,

Problem solved - you just need to "balance" your radiators. Plenty on it if you do a search. Start by almost closing the rads which work well.

 

[Terry1234]

Chris R

Thanks for the reply, i have tried this on serveral occasions and although i have not actually used thermometers, i think i have got the balancing right. What did puzzle me a little bit was the TRV's does it matter if they are on the flow or return, mine seem to be mixed (I know you can get reversable trvs but i wondered if this made a difference).

 

[ChrisR]

From the balancing point of view it doesn't matter which end of the rad has the trv.

If you DID have the balancing right, all the rads would heat up together.
What makes you say you have it right?

 

[Terry1234]

I think i have it right because i have done as per web instructions with the exeption of the thermometers, would you say that these are esential, if so where can i buy them from and how much are they likely to cost?

Thanks for all your help and advice on this it really is appreciated

 

[Terry1234]

O.K i have purchased a thermometer (no more guessing) and plan to do this to the letter, on initial investigation one side of the radiator pipe seems hot and the other seems cold on some radiators. To counter act this do i open the flow or restrict it? Also am i aiming to get the hot pipe cooler or the cold pipe hotter, they don't tell you this in the instructions i have printed off.

Thanks

 

[ChrisR]

Cold pipe hotter.The hard part is getting the "good" rads right, which often means having them almost imperceptibly open.

The flow end should be about the same temp on all the rads, and so should the return, but with heat losses from the pipes the further ones will have cooler flow.

If you've got the best ones just open far enough, and the furtherst(coolest) still aren't getting enough HW, you need bigger or cleaner pipes, or a bigger pump. (or turn the pump up).

If a rad has a TRV it isn't so critical as long as it heats up adequately quickly - it'll turn itself down when the room warms up.

 

[Terry1234]

Chris R

A hughe massive thank you. It took me several attemps and three days to do but i have finally balanced the system succesfully and all radiatirs now get hot. I also turned my pump down to speed setting two which seemed to help.

Thankyou to everyone who posted a reply, now all sorted